Date   

Re: GN boxcar information needed on cars in the 9731 series.

Staffan Ehnbom <staffan.ehnbom@...>
 

The built, or rebuild dates rather, for the GN 9000 series as shown in the diagrams and in photos is 1925.

Staffan Ehnbom

----- Original Message -----
From: gary laakso
To: STMFC@yahoogroups.com
Sent: Monday, October 15, 2012 1:49 AM
Subject: Re: [STMFC] GN boxcar information needed on cars in the 9731 series.



The 9000-9999 boxcars were trussrod boxcars rebuilt with inverted Murphy metal ends and with the 8 truss rods retained with steel center sills. CB&Q used a very similar design and did the same upgrade. Both companies replaced the wood roofs with steel Murphy XLA roof.
The cars were long lasting and 7 made it to January 1, 1959. Of course, that is in revenue service, they soldiered on in MOW service. The 1923 re-build date is correct for accounting and tax purposes, though they were rebuilt cars originally built as early as 1901.

I have 3 of the Westerfield kits ready for decalling and they join the other 14 Westerfield GN trussrod cars and 5 CB&Q truss rod cars. For variety, two of the CGW 1932 ARA boxcars were completed and ready for sides and ends painting. The 3 NP 14000 series double sheathed boxcars are waiting for TruColor NP freight car red paint to arrive.

gary laakso
south of Mike Brock
vasa0vasa@earthlink.net
From: Bob McCarthy
Sent: Sunday, October 14, 2012 3:45 PM
To: STMFC@yahoogroups.com
Subject: [STMFC] GN boxcar information needed on cars in the 9731 series.

Good afternoon!

Jerry Glow sent me some artwork for a GN boxcar #9731 which appears to have been 7'10" IH DS which is rather low for the build date indicated.

Also, according to the artwork the car survived long enough to acquire AB brakes and received a date of 10/52 on the car body. Unfortunately, his customer did not supply information needed to determine what the actual boxcar looked like.

According to Jerry's decal artwork the car was built in 7/23. It shows truss rods. However, I am aware that there were a number of cars built between 1913 (NP) and 1924 (SR) combining both truss rods and either a fishbelly or steel channel stock underframe.

Having just completed a early 1913 NP radial roof truss rod 40' DS 8' IH boxcar, I discovered a later 1913 NP radial roof truss rod/fishbelly 40' DS 8'7" IH boxcar which I also plan to build. This creates the need to know more about the GN boxcar group. They appear to have a 7'10" IH which is low for 1923 and also truss rods. (Perhaps steel or fishbelly underframe as well).

If any one on this list has access to drawings, images, or any other information on the group of boxcars into which GN 9731 falls I would appreciate being contacted off list.

When completed I would be glad to share images of the various boxcars of the 1910-1930 period that I am building with this list.

Thanks,

Bob McCarthy

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]





[Non-text portions of this message have been removed]


Re: Another Shapeways report

Bob McCarthy
 

Rob,

      Please contact me off list.  Have questions about your parts that do not belong on this list.


Thanks,

Bob McCarthy




________________________________
From: Rob Kirkham <rdkirkham@live.ca>
To: STMFC@yahoogroups.com
Sent: Sunday, October 14, 2012 8:02 PM
Subject: Re: [STMFC] Another Shapeways report


 
I see the photos of my latest projects have been approved now. They are at:
<http://groups.yahoo.com/group/STMFC/photos/album/219763914/pic/list?order=ordinal>

Rob Kirkham

Sent: Saturday, October 13, 2012 5:35 PM
To: <STMFC@yahoogroups.com>
Subject: [STMFC] Another Shapeways report

I've posted a number of photos of my own recent experiments with 3d printing
(waiting for them to be approved). These were done by ADC (Advanced Design
Concepts) - but as far as I know they use the same machine and substance as
Shapeways. Overall I am quite happy with the parts I received.

The first photos show tank car underframes for CPR 389xxx series tank cars.
The cars looked a lot like the Athearn single dome tank (and also like an SP
prototype Tony Thompson has written about modelling). I've been muddling my
way through this project for a number of years, but this is the closest I've
come to an acceptable frame model. At this point the issues are in my
design errors - not the material or process used by ADC. that said, I can
see some grain in the part that may show through the paint. And the
particles that are fused to make the part do produce some "noise" when under
magnification. But for frame parts that will be largely hidden beneath
running boards and the tank itself, I think this is acceptable quality for
now.

The other part is an inverted Murphy end used on the CPR's 2975xx series
single sheathed automobile boxcars. The rest of the model is still in
process. Again one can see some waviness in the flat surfaces, and some
imperfections in the corrugations, but overall I think it is a satisfactory
starting point for the model. My photography isn't good enough to show the
rivets along the edges, but they are there too.

I've been using Bestine rubber cement thinner to clean the waxy stuff of the
parts with success so far. A few minutes in that stuff cleans them and
changes the parts from translucent to opaque white and cleans some of the
wax away.

One thing about ADC - they focus on your job so the parts are oriented as
you would like. The auto-box end was modelled laying on the interior side
of the model. Interesting that the view of the back shows more of the
printing texture. I assume that is the wax support - and "yes" it is far
more grainy than any other surface of the model.

By the way this ties into the other thread re the UP boxcars - as, for
example, I believe this process allows one to build the ends without hacking
up Tichy parts. Of course some of you are skilled enough that you don't
hack, but for those of us who do . . . .

Rob Kirkham





[Non-text portions of this message have been removed]


FGE/WFE/BRE at Naperville

Bill Welch
 

Earlier this year I succumbed to my experience of 13 years as a photojournalist when realized as I worked on the FGE/WFE/BRE book that I needed to begin to see the photos I have on the page with text, tables, maps, etc. Then I found exactly the classes I needed at St. Pete College to help me learn Adobe's InDesign and Illustrator and I was also able to purchase their Creative Suite as a student. For several weeks now I have been experimenting and applying the learning.

The long and the short of this is that I will have two Prototype chapters with me at Naperville to show interested folks and see and hear their response. These are chapters include three different groups of refrigerator cars that provide a look at my approach to covering the fleet. If you want to see what I am doing, just ask me for a look.

Among the things I would like responses/opinions on are my choice of page orientation, type size, and the number of photos (am I using too many?).

Bill Welch
2225 Nursery Road; #20-104
Clearwater, FL 33764-7622
727-470-9930
fgexbill@tampabay.rr.com

P.S. While on my way to Naperville, via Galesburg, IL for more research I had dinner in Murfreesboro, TN with two former photojournalist colleagues Sunday and I already have tweaks to make.


Re: Another Shapeways report

Robert kirkham
 

I see the photos of my latest projects have been approved now. They are at: <http://groups.yahoo.com/group/STMFC/photos/album/219763914/pic/list?order=ordinal>

Rob Kirkham

Sent: Saturday, October 13, 2012 5:35 PM
To: <STMFC@yahoogroups.com>
Subject: [STMFC] Another Shapeways report

I've posted a number of photos of my own recent experiments with 3d printing
(waiting for them to be approved). These were done by ADC (Advanced Design
Concepts) - but as far as I know they use the same machine and substance as
Shapeways. Overall I am quite happy with the parts I received.

The first photos show tank car underframes for CPR 389xxx series tank cars.
The cars looked a lot like the Athearn single dome tank (and also like an SP
prototype Tony Thompson has written about modelling). I've been muddling my
way through this project for a number of years, but this is the closest I've
come to an acceptable frame model. At this point the issues are in my
design errors - not the material or process used by ADC. that said, I can
see some grain in the part that may show through the paint. And the
particles that are fused to make the part do produce some "noise" when under
magnification. But for frame parts that will be largely hidden beneath
running boards and the tank itself, I think this is acceptable quality for
now.

The other part is an inverted Murphy end used on the CPR's 2975xx series
single sheathed automobile boxcars. The rest of the model is still in
process. Again one can see some waviness in the flat surfaces, and some
imperfections in the corrugations, but overall I think it is a satisfactory
starting point for the model. My photography isn't good enough to show the
rivets along the edges, but they are there too.

I've been using Bestine rubber cement thinner to clean the waxy stuff of the
parts with success so far. A few minutes in that stuff cleans them and
changes the parts from translucent to opaque white and cleans some of the
wax away.

One thing about ADC - they focus on your job so the parts are oriented as
you would like. The auto-box end was modelled laying on the interior side
of the model. Interesting that the view of the back shows more of the
printing texture. I assume that is the wax support - and "yes" it is far
more grainy than any other surface of the model.

By the way this ties into the other thread re the UP boxcars - as, for
example, I believe this process allows one to build the ends without hacking
up Tichy parts. Of course some of you are skilled enough that you don't
hack, but for those of us who do . . . .

Rob Kirkham


Re: GN boxcar information needed on cars in the 9731 series.

gary laakso
 

The 9000-9999 boxcars were trussrod boxcars rebuilt with inverted Murphy metal ends and with the 8 truss rods retained with steel center sills. CB&Q used a very similar design and did the same upgrade. Both companies replaced the wood roofs with steel Murphy XLA roof.
The cars were long lasting and 7 made it to January 1, 1959. Of course, that is in revenue service, they soldiered on in MOW service. The 1923 re-build date is correct for accounting and tax purposes, though they were rebuilt cars originally built as early as 1901.

I have 3 of the Westerfield kits ready for decalling and they join the other 14 Westerfield GN trussrod cars and 5 CB&Q truss rod cars. For variety, two of the CGW 1932 ARA boxcars were completed and ready for sides and ends painting. The 3 NP 14000 series double sheathed boxcars are waiting for TruColor NP freight car red paint to arrive.

gary laakso
south of Mike Brock
vasa0vasa@earthlink.net
From: Bob McCarthy
Sent: Sunday, October 14, 2012 3:45 PM
To: STMFC@yahoogroups.com
Subject: [STMFC] GN boxcar information needed on cars in the 9731 series.


Good afternoon!

Jerry Glow sent me some artwork for a GN boxcar #9731 which appears to have been 7'10" IH DS which is rather low for the build date indicated.

Also, according to the artwork the car survived long enough to acquire AB brakes and received a date of 10/52 on the car body. Unfortunately, his customer did not supply information needed to determine what the actual boxcar looked like.

According to Jerry's decal artwork the car was built in 7/23. It shows truss rods. However, I am aware that there were a number of cars built between 1913 (NP) and 1924 (SR) combining both truss rods and either a fishbelly or steel channel stock underframe.

Having just completed a early 1913 NP radial roof truss rod 40' DS 8' IH boxcar, I discovered a later 1913 NP radial roof truss rod/fishbelly 40' DS 8'7" IH boxcar which I also plan to build. This creates the need to know more about the GN boxcar group. They appear to have a 7'10" IH which is low for 1923 and also truss rods. (Perhaps steel or fishbelly underframe as well).

If any one on this list has access to drawings, images, or any other information on the group of boxcars into which GN 9731 falls I would appreciate being contacted off list.

When completed I would be glad to share images of the various boxcars of the 1910-1930 period that I am building with this list.

Thanks,

Bob McCarthy

[Non-text portions of this message have been removed]


Re: Another Shapeways report

Tom Madden
 

Dennis wrote:

I am now realizing that the process used by Shapeways has another pitfall; the basic process can't build parts with overhangs, since there would be nothing to support the first layer of resin that hangs past the previous layer, so the process used by Shapeways builds a wax structure to support this first layer. Unfortunately, it appears that the wax construction is done at a considerably coarser resolution than the actual part, and any surface built against the wax picks up this coarser resolution.
Time to clear up some misconceptions. There are two inkjet-type heads mounted back to back. One contains body material, the other contains support material, in this case wax. Each head is capable of dispensing its material onto any pixel in a layer in the same pass. Same resolution, same layer thickness. On our PolyJet machine, a high-intensity UV light is mounted on the print head in the trailing position and cures the material almost as fast as it is deposited, "almost" being the key word. More on that shortly. I don't know if Shapeways' MultiJet FUD process uses a moving lamp or flashes each layer as it is completed, but the effect is the same - deposit first, then cure.

Think of your part suspended above the build platform and casting a shadow. A few layers of wax are laid down in the exact pattern of that shadow. This permits the part to be removed from the platform. If your part is, say, a cube, no more wax would be required - every layer from there on up would be body material only. If your part was a pyramid, built with the point up, that too would require no more wax. But if you built your pyramid with the point down, the first layer above the wax base would be all wax except one lonely spot of body material in the center. (Keep thinking of the shadow of the upside-down pyramid.) In the next layer the center spot would be larger and recognizably square, but the rest of the layer would be wax. And so on, until the top layer, which would be all body material. The point is, there has to be something underneath the body material on every layer. If it's not other body material, it has to be wax. If you were building a pyramid with a cube balanced on the tip, the pyramid would be completely encased in the wax that provides support for the bottom of the cube. Every overhanging portion of an object will have wax support material under the overhang.

Back to that "almost" issue. Uncured body material is a gel. In the few milliseconds after a pixel of body material is laid down and before it is cured, it conforms to the underlying surface and to its neighbors. Curing the material bonds it to that underlying surface, if that surface is body material. The problems come at the interfaces. An uncured pixel of body material in the middle of a row will merge with its neighbors, while the end pixels in contact with air will pretty much hold their shapes. But if there's wax at the end of that row, the end pixel will merge with the wax pixel and lose its shape. Think of a vertical sidewall as a matrix of tiny marbles. In the absence of wax, under magnification the sidewall will appear uniformly granular. But where there was wax, those tiny marbles that were in contact with the wax will have oozed out from the surface, leaving a rough patch. You can see that in the faces of the double steam control box that was built standing on one end:
http://www.pullmanproject.com/Shapeways10.jpg

The three wax tracks go all the way up to the overhanging cleats on the mirrored component. Fortunately, I only needed one of each (left & right) to serve as resin casting masters, and the part that was built face up provided those.

Hope this all helps understand the process.

Tom Madden


Re: The right trucks - and the right bearings, for the archives - wrap-up

devansprr
 

--- In STMFC@yahoogroups.com, Frank Greene <frgreene290@...> wrote:

On 10/14/2012 12:21 AM, Dave Evans wrote:
... 1b) The C&O cars included a fat white strip under part of Chesapeake and Ohio to indicate they were roller bearing equipped. Steve Lucas has a 1958 ETT that makes note of this mark, and instructs crews in special handling of RB equipped cars, since the slippery little devils will roll a lot more at low speeds than plain journal bearing equipped cars. It would be useful to know if other ETT's of the late STMFC era had similar notations, and if that might mean specific marks need to be included on 1950's STMFC models from railroads other than the C&O.

Scanning through several Southern Railway ETTs from 1954-'58 did not
identify any special instructions for roller bearing equipped cars. On
roller bearing equipped boxcars and covered hoppers, Southern Railway
stenciled "[brand name] ROLLER BEARINGS" in 2 1/2" letters on the side
sill near the right bolster.


2a)The limited deployment of RB's in the STMFC era had little impact on freight train performance, although it did impact some individual car handling tasks, such as the C&O ETT instruction to not hump RB equipped cars and apply special practices for spotting RB equipped cars. It would be interesting to know if other ETT's and/or rulebooks had similar rules/guidance.

Why not hump roller bearing equipped hopper cars?

--

Frank Greene
Memphis, TN
Frank,

Thanks for checking the ETT's. Where is it written about the cars being labeled RB equipped? I wonder if it was an AAR rule? Or each railroad did their own thing?

At the low speeds of a hump yard, a roller bearing equipped car would roll much further, and could reach the string of cars at the end of the track at a much higher speed.

For an automatic retarder, I would expect the amount of retarding would need to be changed for a roller bearing equipped car versus a plain bearing equipped car (I think automatic retarders were already adjusting for car weight). Over on OpSig a professional railroader indicated that modern hump yard retarders now take wind speed/direction into account because the cars are so free wheeling.

I suspect it would also require very different handling by a hump rider manually controlling the brake (although one would expect quick adaptation if the riders were instructed in the difference.) Perhaps C&O was reacting to damaged cargo from too-high hump impacts, or possibly injuries to riders?

So I suspect the Southern RB marking was to at least help someone working a hump yard (retarder controls or riders - either one).

Were hump riders ever outlawed? Or did the railroads find them too expensive (in pay or in damaged contents)?

Dave Evans


GN boxcar information needed on cars in the 9731 series.

Bob McCarthy
 

Good afternoon!

     Jerry Glow sent me some artwork for a GN boxcar #9731 which appears to have been 7'10" IH DS which is rather low for the build date indicated. 

Also, according to the artwork the car survived long enough to acquire AB brakes and received a date of 10/52 on the car body.  Unfortunately, his customer did not supply information needed to determine what the actual boxcar looked like.

     According to Jerry's decal artwork the car was built in 7/23.  It shows truss rods.  However, I am aware that there were a number of cars built between 1913 (NP) and 1924 (SR) combining both truss rods and either a fishbelly or steel channel stock underframe.

     Having just completed a early 1913 NP radial roof truss rod 40' DS 8' IH boxcar, I discovered a later 1913 NP radial roof truss rod/fishbelly 40' DS 8'7" IH boxcar which I also plan to build.  This creates the need to know more about the GN boxcar group.  They appear to have a 7'10" IH which is low for 1923 and also truss rods.  (Perhaps steel or fishbelly underframe as well).


     If any one on this list has access to drawings, images, or any other information on the group of boxcars into which GN 9731 falls I would appreciate being contacted off list.

     When completed I would be glad to share images of the various boxcars of the 1910-1930 period that I am building with this list.


Thanks,

Bob McCarthy

[Non-text portions of this message have been removed]


Re: The right trucks - and the right bearings, for the archives - wrap-up

Frank Greene
 

On 10/14/2012 12:21 AM, Dave Evans wrote:
... 1b) The C&O cars included a fat white strip under part of Chesapeake and Ohio to indicate they were roller bearing equipped. Steve Lucas has a 1958 ETT that makes note of this mark, and instructs crews in special handling of RB equipped cars, since the slippery little devils will roll a lot more at low speeds than plain journal bearing equipped cars. It would be useful to know if other ETT's of the late STMFC era had similar notations, and if that might mean specific marks need to be included on 1950's STMFC models from railroads other than the C&O.

Scanning through several Southern Railway ETTs from 1954-'58 did not identify any special instructions for roller bearing equipped cars. On roller bearing equipped boxcars and covered hoppers, Southern Railway stenciled "[brand name] ROLLER BEARINGS" in 2 1/2" letters on the side sill near the right bolster.


2a)The limited deployment of RB's in the STMFC era had little impact on freight train performance, although it did impact some individual car handling tasks, such as the C&O ETT instruction to not hump RB equipped cars and apply special practices for spotting RB equipped cars. It would be interesting to know if other ETT's and/or rulebooks had similar rules/guidance.

Why not hump roller bearing equipped hopper cars?

--

Frank Greene
Memphis, TN


Re: L&N and NKP gons and flat

Steven D Johnson
 

Bill,



Thanks for the information on the photos.



I have a photocopy of what I think is a builder's photo of L&N gondola #
26000, the first of 1,000 of those shorter gons that you mentioned. Also
have a copy of a ca. late 1940s lettering diagram for those cars.



Steve Johnson





From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On Behalf Of
lnbill
Sent: Saturday, October 13, 2012 1:59 PM
To: STMFC@yahoogroups.com
Subject: [STMFC] Re: L&N and NKP gons and flat





Steve

L&N 25884 from Bob's is a nice broadside shot in Wilson, NC on 2-2-1952 w/a
reweigh date of 1950. The Ameling photos of L&N 25823 are 1957 in Sarasota,
FL. Stenciling identical to 25884. These three include good views of each
end. L&N 25800, the Builder's Photo, cataloged as PA 182717, is a 3/4 shot
giving a good view of the "B" end.

BTW, Bob's is also the source for L&N 26371, which is a shorter gon also
w/wood sides and stake pockets. Southern had a similar car, both of which
resemble the PRR GR/GRa.

With Chad's new kit, virtually every gondola owned by the L&N into the
1950's can now be modeled in HO except the above small wood side gon.
Athearn has their (and NC&StL's) 65-ft mill gon. Westerfield's 45-ft USRA
mill gon can be used for the L&N's copy of these, Sunshine has their 40-ft
gon kit (and NC&StL's) and InterMountain has their USRA 40-ft composite gon.

Life is good!

Bill Welch

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com> , "Steven D
Johnson" <tenncentralrwy@...> wrote:

Bill,



What are the dates on the one from Bob's Photos and those from the Ameling
collection?



Thanks,



Steve Johnson





From: STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
[mailto:STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com> ] On Behalf
Of
lnbill
Sent: Saturday, October 13, 2012 10:13 AM
To: STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
Subject: [STMFC] Re: L&N and NKP gons and flat





Photos of the L&N gons are available. There is one available from Bob's
Photos and I think my MtV Builder's Photo came from the Merrilee's
Collection at the Archives of Canada. Then there is a group of 3 photos
shot
by Howard Ameling from different angles of a car loaded w/coal. I think
Mr.
Ameling's photos are now available through Cleveland St. Univ. where his
collection is deposited. My memory is I made these available to Chad to
assist his pattern making and the necessary decals.

Bill Welch

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com> , "Chad"
<chadboas@> wrote:

Steve,
Yes it is. The flats are from the 22000-22249, 24300-24549, and
24550-24799.
Chad Boas

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com> , "Steven D
Johnson" <tenncentralrwy@> wrote:

Chad,



Is your L&N gondola based on the 25800-25999 series cars built by Mt.
Vernon
Car Mfg. Co. in 1928?



Steve Johnson





From: STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com>
[mailto:STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com> ] On Behalf
Of Chad
Sent: Friday, October 12, 2012 9:31 PM
To: STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com>
Subject: [STMFC] Re: L&N and NKP gons and flat





Thanks, Bill
These are from your suggestion. I think there was a NKP flat car made
from
these. Still looking for conformation. There were some flats listed
that
were 50'9".
Also, I added photos of the NKP. Should be able to get it painted over
the
weekend.
Chad Boas

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com> , "lnbill"
<fgexbill@> wrote:

Okay, on 3 let's all chant Chad--Chad--Chad--you're the
man--Chad--...

One, two, ...

Bill Welch

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com>
<mailto:STMFC%40yahoogroups.com> , "Chad"
<chadboas@> wrote:

All,
The next round of kits will be the wood side gons for L&N and NKP.
The L&N is a 46'9" and can be either a flat car or can be ordered
with
the sides parts. The NKP is a 50'9" wood side gon. The kits will
include
the
Red Caboose pockets for the wood sides.
I have added a file called L&N and NKP gons and flat. The L&N car
is
there and I am working on getting a picture of the NKP.
I will have these cars avalible for Naperville.
Contact me off list for more information.
Thanks, Chad Boas











Lining Stock Cars

Guy Wilber
 

For Mr. Harding and interested others;

I found a photo of the interior of a stock car (circa 1927) that had been lined with what was termed, "Construction Paper". It does indeed seem to be classic roofing felt paper. I had previously commented that I didn't think that roofing felt would have been used, but am proved wrong by the photo and accompanying text.

The paper is applied on the inside of the car with lath running both parallel to the stock car slats as well as perpendicular lath (appearing to be about every six feet or so). Paper seems to go up about six feet on the inside of the car. The car was bedded with the typical sand and a generous amount of hay. The car was specified for cattle, but was likely typical of cars lined and bedded for hogs or other livestock as well.

Regards,

Guy Wilber
Reno, Nevada










[Non-text portions of this message have been removed]


Trying to contact Schuyler Larrabee

npin53
 

Could Schuyler Larrabee please contact me off list? Thank you.

Aaron


Re: The right trucks - and the right bearings, for the archives - wrap-up

mopacfirst
 

I appreciate the engineering analysis that goes into subjects like this. ASME RTD continues to publish papers on improvements in this and related subjects, which are more generally referred to as 'truck-rail dynamics'.

But I will offer an anecdote.

In 1968 or 69, when I was still in high school, I traveled around town with a friend of mine who had a talent for trying things he shouldn't, like climbing on top of a boxcar to get a better view of the main line -- at 2 am. The security guard who saw us wasn't sympathetic in the least.

One Saturday, we were near an industry known as Southwest Grease which was served by the Santa Fe from the south end and MoPac from the north end. There was a track coming from the south end, which crossed a street and had loading docks adjacent, with a Santa Fe mechanical reefer spotted at the dock. (I know it was orange, and it was a Santa Fe car, so I'm pretty sure that would have meant it was an RPL.) This would have been a fairly new car with outside-post construction, so it would have to have had roller bearings.

Well, this guy got the bright idea to climb the car end and release the brake to see what would happen. The B end was the end away from the street, so no other bystander could see this. Sure enough, after a couple turns of the brakewheel, the car started to roll -- into the street. It got halfway into the two lane street, or about half its length, into the street before he got it stopped.

We got out of there real quick. Fortunately, this being Saturday, there were no vehicles passing on the street, which meant no witnesses.

Ron Merrick

--- In STMFC@yahoogroups.com, "Dave Evans" <devans1@...> wrote:
<snip>
All,

Begging the moderator's indulgence one last time, I wanted to wrap up my part of this thread <snip>


Re: The right trucks - and the right bearings, for the archives - wrap-up

devansprr
 

--- In STMFC@yahoogroups.com, "Aley, Jeff A" <Jeff.A.Aley@...> wrote:

Tim,

Thanks for letting me know your opinion.

So far, I judge this thread to be acceptable.

Regards,

-Jeff Aley
Moderator, STMFC

All,

Begging the moderator's indulgence one last time, I wanted to wrap up my part of this thread to include some Internet research I conducted over the past few evenings. I am also sympathetic to Tim O'connor's concern that this was wandered off topic.

Therefore this post has been divided into four topics:

1) STMFC modeling that may need to reflect bearing types (journal vs. roller). Clearly STMFC content.

2) The impact of roller bearings on STMFC era operations – marginally on topic

3) Relating model railroad wheel set selection to journal vs. roller bearings (slight tongue in cheek)

4) The prototype engineering behind all this, including an update to modern investigations into freight train resistance.

The sections are ordered to reflect what I suspect is a decreasing level of interest among some on this list:

1) STMFC features that distinguished roller bearings (RB) In a manner that might be reflected n STFMC models:

1a) The first large scale RB installation to freight cars (besides testing), was a refit of 300 UP stock cars in 1947, followed by 1000 new C&O hoppers. The UP cars, as retrofits, featured journal box covers that are difficult to distinguish from plain journal bearings. But the C&O hoppers (79000 series) clearly have journal covers that look very similar to passenger car RB covers of the day – they do not resemble plain bearing journal boxes with flip up lids for maintaining journal bearing oil levels and packing/wiping materials.

1b) The C&O cars included a fat white strip under part of Chesapeake and Ohio to indicate they were roller bearing equipped. Steve Lucas has a 1958 ETT that makes note of this mark, and instructs crews in special handling of RB equipped cars, since the slippery little devils will roll a lot more at low speeds than plain journal bearing equipped cars. It would be useful to know if other ETT's of the late STMFC era had similar notations, and if that might mean specific marks need to be included on 1950's STMFC models from railroads other than the C&O.

1c) RB installations began in earnest in the early 1950's, and the ASME book indicates that freight cars were being equipped with roller bearings at a rate of just under 1% of the national fleet per year throughout the mid-to-late 50's. All of this was long before RB's were mandated, so it appears that RR's were installing RB's on freight cars used in captive service. If most RB installs were on new cars, and they were generally used in captive service, and if about 2.5% of the nation's freight car fleet was replaced every year, then as much as 30 to 40% of new car construction in the mid to late 50's would have been RB equipped. So this is a distinctive feature that 1950's era modelers may need to research.

1d) For the STMFC era, it appears that RB installs were limited to cars in captive service. Candidates include merchandise express cars, stock cars, hoppers, and I am not sure what else, although I suspect many on the list will be able to provide insight into this topic. Conversely I suspect that private owner cars (such as tank cars) would not be RB equipped (why "waste" their money on more expensive bearings – it wouldn't save them any money). Perhaps some of the RR owned reefer companies would install RB's. I would think that general service XM's would not. RB installation on new and rebuilt cars was not mandated until after the STMFC era.

1e) Coming full circle to the original topic of this thread, it would seem that for those modeling late in the STMFC period, accurate model trucks will need to reflect the proper type of bearing – plain journal bearing, or roller bearing.

2) Impact of bearings on STMFC operations.

2a)The limited deployment of RB's in the STMFC era had little impact on freight train performance, although it did impact some individual car handling tasks, such as the C&O ETT instruction to not hump RB equipped cars and apply special practices for spotting RB equipped cars. It would be interesting to know if other ETT's and/or rulebooks had similar rules/guidance.

2b) The important operations lesson from this investigation is the MUCH higher plain bearing friction at very low speeds, and especially when stopped. With plain bearing starting friction being as much as 10 times the rolling friction at 10 mph, the starting friction helps explain the need to "take slack" before starting a long train during the steam era, and the need to quickly get cars moving, and keep them moving, at speeds of several miles per hour. I could not find an authoritative source describing a critical "minimum" speed, below which a long train on level or uphill grades was likely to stall. Based on the data I have reviewed, my "best guess" is that the minimum speed would be around 3 mph. This could explain why STMFC era trains, especially those powered by steam, were "walked out" when starting at a walking pace – not a crawling pace. Perhaps videos can confirm this, but personally I will no longer be concerned about trying to have model steam locomotives pull long freight trains at 1 smph – simply not prototypical.

2c) But in the end, once above 10 mph, the difference in rolling resistance between plain journal bearings and roller bearings is equivalent to only a 0.1% grade, which also means RB's did not lead to much higher train tonnages, because at speed the other sources of resistance are much greater. But considering that a journal bearing's starting friction was equivalent to a 1.75% grade, it is possible that tonnage ratings for ruling grades could be increased for steam powered trains since it would be easier to restart on a grade if RB equipped, and then work up the grade at lower speeds without stalling. (Note that when starting a plain bearing train, by taking slack, only a few cars are in the very high friction regime at any given instant – the rest of the train either hasn't started moving yet (still slack between it and the locomotive,) or the moving part of the train is already up around 3 mph, where friction is likely 1/4 or less of the starting friction).

2c) Engineering data would suggest that plain bearing equipped cars stopped on a 1.5% grade would likely stay put, even without brake application. So no worries for spotting plain bearing equipped cars on slight grades. RB equipped cars could start rolling on grades as gentle as 0.05-0.1%.

3) Unfortunately for Doug Harding and Bill Schneider, there is no way to simulate plain bearing friction on a model railroad - good wheel sets are a good approximation of plain bearings above 3 to 4 smph, and lousy wheel sets are only accurate when stopped, or just starting (But with so much drag above 3 smph there is the issue of whether or not the train could climb a helix – as discussed before). Conversely, really good wheel sets may approach prototype RB equipped car resistance – although RB's contribute a very small portion of modern freight car resistance. (See the next section).

4) For those willing to hang in there, some interesting engineering data is available on the web:

4a) Car resistance is much more complicated than just bearing friction/resistance. Car "resistance" sources include:

- Bearing "friction"

- Wheel/rail losses from the local compression of both the wheel tread and rail head as the wheel rolls along (the smallest "loss" term, since it does not involve friction. Often ignored)

- Wheel/rail friction – wheel flanges scraping the sides of railheads – this source of resistance is greater than modern RB's

- Grade (20 pounds resistance per ton, per percent grade – this is the physics of lifting the car up the hill and is unrelated to friction)

- Curvature

- Aerodynamic

4b) I found several resistance formulas. The Davis formula was the one I found most widely quoted. But different railroads appear to have formulated it with different terms. A CN document that discusses the change in their use of the equation over time is available for download:

http://5at.co.uk/uploads/Articles%20and%20papers/CANADIAN%20RESISTANCE%20PAPER.PDF

I recommend you read it if you want an introduction into the sources of train resistance - it is only 6 pages and does not overwhelm one with detailed equations. I would warn the reader to note the change in the definition of the term W over time. It can lead to some confusion when trying to follow the change in CN's application of the Davis equation over time(See footnote).

It makes for very interesting reading, and rather than my trying to compose a detailed summary of it, I will highlight one topic that appears authoritatively stated that has been discussed in this thread, and make an observation about how to interpret older bearing friction data:

When it comes to starting cars, the CN document recommends that 35 pounds per car ton be used as the starting resistance of a plain bearing equipped car when below freezing, and 25 pounds per ton above freezing! The same CN document suggests starting resistance for RB cars is 5 lbs per ton. But this includes ALL sources of resistance when starting a train.

The other observation from reading the CN document, it is that I am no longer sure how to interpret the 1931 Timken bearing test results in the ASME book I have been quoting. The vertical axis of the figure in the book is labeled "resistance", the horizontal axis is speed. The test was conducted with the PRR, and I have other PRR test reports that make it quite clear that the PRR test department was very much aware of aerodynamic losses. Plus the increase in resistance as speed increased, as shown in the figure, is gradual, and does not reflect the increase that would result from aerodynamics. So it appears aerodynamic resistance has been taken out of the data. Assuming the data was collected on level and straight track, that still leaves other sources of train resistance unrelated to bearings that need to be accounted for. For modern bearing cars, the primary source of resistance is now the tendency of trucks to wobble such that the wheel flanges come into contact with the sides of the rail head (truck "hunting"). The CN data reports that in the early 1990's this resistance was as high as 2.1 pounds per ton for a loaded car. So without access to the original test report, there is no way to know if the 1931 Timken bearing report, with the minimum resistance of 3.1 pounds per ton at 17 mph for plain bearings, and 2.6 pounds per ton minimum at 15 mph for RB equipped cars, is only reporting bearing resistance or all train resistance other than aerodynamic. Unless the full PRR/Timken report can be found, this will remain a mystery – did the 1931 Timken resistance data report only bearing resistance?

The CN document is through 1992, and there has been a lot of recent prototype research due to the increase in fuel costs and the desire of modern RR's to increase their cost competitiveness against trucks by reducing fuel consumption.

There are many interesting documents available on the web, but one recent presentation that also provide some interesting information about the scope of Intermodal rail shipments in the US is from BNSF:

http://ict.uiuc.edu/railroad/CEE/pdf/PPT%27s/fall08/Stehly_10-24.pdf

4c) Some general observations from this and several other sources –

- My engineering experience would suggest (but I cannot find this in an authoritative source) that in the STMFC era, plane journal bearing resistance was the dominant contributor to "rolling" resistance. With the significant reduction in bearing friction achieved by roller bearings, the other sources of friction have become much more evident. With today's fuel costs the RR's are working to reduce the friction from these other sources using new technologies. Top of rail lubricants, lubricants in curves, self steering trucks, and several other areas are the focus of funded research and equipment development, all to reduce rolling resistance. There has even been work to optimize double stack loading to reduce the aerodynamic drag induced by large gaps between each stack.

- Modern roller bearings exhibit almost constant "resistance" across the full speed range for freight trains. Most importantly, RB starting resistance is only slightly higher than rolling, and it is an order of magnitude less than plain journal bearing starting resistance. So steam locomotives in excursion service can now start the train they can pull!

- Surprisingly, it is hard to find published bearing rolling resistance data. I think because it is a problem the industry considers solved – bearings are standardized around the Timken AP2 taper concept. But BNSF did publish a number – an amazingly low 0.6 pounds resistance per car ton

4d) Modern friction reduction work – In addition to curve lubricants and top-of-rail (TOR) lubricants, there appears to be significant research into self steering trucks designed to reduce truck hunting, and in some cases, keep the axles of a truck in a curve pointing towards the center of the curve (the axles not parallel). There is data that suggest that the more modern self-aligning/self-steering trucks actually change the age old curve compensation of 0.04% grade equivalent for each degree of curvature, and cut it in half, or even more for some of the most advance trucks when operated in conjunction with rail lubrication systems. Some pretty wild stuff.

Once again savings from these more expensive trucks provide the most savings to the operator, so it seems like some of the most advanced freight car truck development is being applied to cars in captive service carrying heavy cargoes over many miles every day, and those cars being, you guessed it, coal hoppers – 60 years after C&O was the first to incorporate roller bearings into their hoppers. Déjà Vu.

Dave Evans

Footnote – within the CN document, the definition of the term W in the Davis equation changes. Note that the Davis formula produces the resistance in pounds per ton. So taking the value of R, and multiplying it by the trailing tons, yields the drawbar pull. In section 2.1.2, all Davis equations use W in weight (in tons) PER AXLE. In section 2.1.3.b, W is weight of the car. In 2.1.3.f, W is back to weight in tons per axle.


Re: L&N and NKP gons and flat

Brian Carlson
 

1983 according to the article in the Spring 1998 NKPHTS magazine which is available and in my spare room if anyone wants one. Weblink below. NKP cars were black.



Brian J Carlson, P.E. 2972L

NKPHTS Special Projects Director

PO Box 272, Highland, MD 20777-0272

http://nkphts.org/home.html



From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On Behalf Of Ray Breyer
Sent: Saturday, October 13, 2012 10:44 PM
To: STMFC@yahoogroups.com
Subject: Re: [STMFC] Re: L&N and NKP gons and flat--Who is doing the decala and what colors were these cars painted?





Hi Brian,

They're the composite gons built by Standard Steel in 1923. Last ones seem to FINALLY drop off the N&W roster some time in the mid-1980s.


Ray Breyer
Elgin, IL


Re: L&N and NKP gons and flat--Who is doing the decala and what colors were these cars painted?

Ray Breyer
 

Hi Brian,


They're the composite gons built by Standard Steel in 1923. Last ones seem to FINALLY drop off the N&W roster some time in the mid-1980s.

 
Ray Breyer
Elgin, IL


________________________________
From: Brian Carlson <prrk41361@yahoo.com>
To: STMFC@yahoogroups.com
Sent: Saturday, October 13, 2012 9:30 PM
Subject: RE: [STMFC] Re: L&N and NKP gons and flat--Who is doing the decala and what colors were these cars painted?

Chad I may have missed these but what NKP series are these 70000-70499? If so do you have the NKPHTS article on them?



Brian J. Carlson, P.E.

Cheektowaga, NY



From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On Behalf Of Chad
Sent: Saturday, October 13, 2012 8:15 PM
To: STMFC@yahoogroups.com
Subject: [STMFC] Re: L&N and NKP gons and flat--Who is doing the decala and what colors were these cars painted?



 

Jerry was working on them but I havent herd from him in a while. I am going to use the scrap box and some Microscale letters for the L&N and Microscale MC-4243 NKP Cabooses decale sheet has the small "NICKEL PLATE ROAD".
Chad Boas

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com> , "gary laakso" <vasa0vasa@...> wrote:

Who is preparing the decals for these cars and what colors were they painted? I checked my sources and found nothing on either the gons or the flat cars.
However, I did complete (weights to be added tomorrow) 9 of Chad’s Great Northern flat cars and they are really well done.
gary laakso
south of Mike Brock
vasa0vasa@...










[Non-text portions of this message have been removed]



------------------------------------

Yahoo! Groups Links



[Non-text portions of this message have been removed]


Re: L&N and NKP gons and flat--Who is doing the decala and what colors were these cars painted?

Brian Carlson
 

Chad I may have missed these but what NKP series are these 70000-70499? If so do you have the NKPHTS article on them?



Brian J. Carlson, P.E.

Cheektowaga, NY



From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On Behalf Of Chad
Sent: Saturday, October 13, 2012 8:15 PM
To: STMFC@yahoogroups.com
Subject: [STMFC] Re: L&N and NKP gons and flat--Who is doing the decala and what colors were these cars painted?





Jerry was working on them but I havent herd from him in a while. I am going to use the scrap box and some Microscale letters for the L&N and Microscale MC-4243 NKP Cabooses decale sheet has the small "NICKEL PLATE ROAD".
Chad Boas

--- In STMFC@yahoogroups.com <mailto:STMFC%40yahoogroups.com> , "gary laakso" <vasa0vasa@...> wrote:

Who is preparing the decals for these cars and what colors were they painted? I checked my sources and found nothing on either the gons or the flat cars.
However, I did complete (weights to be added tomorrow) 9 of Chad’s Great Northern flat cars and they are really well done.
gary laakso
south of Mike Brock
vasa0vasa@...







Re: Another Shapeways report

Robert kirkham
 

by the way, once approved the photos will be in the RP ladders folder in the photos section.


Rob Kirkham
--------------------------------------------------
From: "Rob Kirkham" <rdkirkham@live.ca>
Sent: Saturday, October 13, 2012 5:35 PM
To: <STMFC@yahoogroups.com>
Subject: [STMFC] Another Shapeways report

I've posted a number of photos of my own recent experiments with 3d printing
(waiting for them to be approved). These were done by ADC (Advanced Design
Concepts) - but as far as I know they use the same machine and substance as
Shapeways. Overall I am quite happy with the parts I received.

The first photos show tank car underframes for CPR 389xxx series tank cars.
The cars looked a lot like the Athearn single dome tank (and also like an SP
prototype Tony Thompson has written about modelling). I've been muddling my
way through this project for a number of years, but this is the closest I've
come to an acceptable frame model. At this point the issues are in my
design errors - not the material or process used by ADC. that said, I can
see some grain in the part that may show through the paint. And the
particles that are fused to make the part do produce some "noise" when under
magnification. But for frame parts that will be largely hidden beneath
running boards and the tank itself, I think this is acceptable quality for
now.

The other part is an inverted Murphy end used on the CPR's 2975xx series
single sheathed automobile boxcars. The rest of the model is still in
process. Again one can see some waviness in the flat surfaces, and some
imperfections in the corrugations, but overall I think it is a satisfactory
starting point for the model. My photography isn't good enough to show the
rivets along the edges, but they are there too.

I've been using Bestine rubber cement thinner to clean the waxy stuff of the
parts with success so far. A few minutes in that stuff cleans them and
changes the parts from translucent to opaque white and cleans some of the
wax away.

One thing about ADC - they focus on your job so the parts are oriented as
you would like. The auto-box end was modelled laying on the interior side
of the model. Interesting that the view of the back shows more of the
printing texture. I assume that is the wax support - and "yes" it is far
more grainy than any other surface of the model.

By the way this ties into the other thread re the UP boxcars - as, for
example, I believe this process allows one to build the ends without hacking
up Tichy parts. Of course some of you are skilled enough that you don't
hack, but for those of us who do . . . .

Rob Kirkham

--------------------------------------------------
From: "soolinehistory" <destorzek@mchsi.com>
Sent: Saturday, October 13, 2012 1:08 PM
To: <STMFC@yahoogroups.com>
Subject: [STMFC] Re: Another Shapeways report



--- In STMFC@yahoogroups.com, "Rob Kirkham" <rdkirkham@...> wrote:

Curious about the preparation you did on this part before priming Dennis?
Just wondering whether any of the distortion might be the waxy support
material they use? Not that I'm getting completely clean surfaces
either,
but thought I'd ask.


Rob Kirkham
That's what I'm wondering, Rob. Hey, I don't have any inside track on
this, I just submitted my part file through the automated front end of the
web site, like anybody else. I would have thought they would have built
the part with the flat disk surface that makes the end of the valve facing
up, to give it the best quality, but apparently not. I actually submitted
a dozen of these, joined together on a "runner", and I think they built it
standing on end. It really doesn't matter, since the purpose of my test is
to see what kind of quality can be had on ALL of the surfaces. This is the
perfect part for a test, as far as I'm concerned, there is no "show face",
they are ALL equally important.

Let me address Dave's comment about "noise". It appears that the best
quality surface is the one that is "normal" to the print process, that is,
flat and parallel, like a sheet of paper relative to the print head of a
ink jet printer. These surfaces will be flat and smooth, as the face of
Tom's boxes are. The next best quality will be on surfaces that are
perpendicular to the normal, because each layer should end at the same
point. The problem is they don't; there are minute differences in both the
size and position of each dot of resin deposited, and the result is a
certain amount of surface noise. The next worst surfaces are going to be
those that are round, or at an angle to normal, because there is the
possibility that the edges of the layers will actually show.

I am now realizing that the process used by Shapewys has another pitfall;
the basic process can't build parts with overhangs, since there would be
nothing to support the first layer of resin that hangs past the previous
layer, so the process used by Shapeways builds a wax structure to support
this first layer. Unfortunately, it appears that the wax construction is
done at a considerably coarser resolution than the actual part, and any
surface built against the wax picks up this coarser resolution. Tom
pointed this out when discussing a unsuccessful earlier attempt of his,
and If I can borrow a link to his photo:

http://www.pullmanproject.com/Shapeways10.jpg

You can clearly see the striations where the part was built against the
wax supports that were needed to build the overhanging features. I believe
I'm seeing this same effect on the bottom angular surface of the bowl on
the bottom of my valve:

http://www.flickr.com/photos/25967611@N04/8077677749/in/set-72157623125645997

I have no idea why they would degrade the resolution of the process by
using a coarser resolution for the support material, but it appears they
have.

I'm wondering if these fused disposition process (FDM) is ever going to
meet our needs. However, I see stereiolithography (SLA), where the part is
grown from liquid polymer in a tank, has considerably finer layer
resolution. Here's a video of the process. Scroll to the end to see the
finished parts:

https://www.youtube.com/watch?feature=player_embedded&v=l2SCrahu2fo

Asiga is a new low cost (relatively) entrant into the field, here is some
comments from their discussion forum:

====================================
Our system has two main factors that affect build quality of the parts,
these are listed below:

1. Image Resolution
This refers to the size of the pixel in the exposed image. The Pico and
Pico Plus39 have a 39 micron pixel size, the Plus33 has a 33 microns pixel
and the Plus27 a 27 microns pixel. The smaller the pixel the sharper the
exposed image and the higher quality surface finish and detail resolution.

2. Layer Thickness
The thinner the print layer, the less visible the stepping. Our range of
printers have presets from 25 microns through to 150 microns and you can
select which layer thickness you require depending on the part you are
printing. The 25 microns layer thickness will achieve a much better part
resolution compared to the 150 microns style. You can also customize this
yourself and print in 1 micron increments if you wish.

A combination of these will determine the resolution of a printed part.

Please let us know if you require clarity. If you are unsure which
machine suits your application then let us know what industry/product you
are producing.

Asiga_Support
===================================

The build envelope on these machines is somewhat limited; 35 x 22 x 75mm
for the finest resolution printers. That's 1 3/8 x 7/8 x 3 inches,
approximately. Big enough for parts, not for complete carbodies.

Unfortunately, SLA is a single component system, so overhangs require
support structures, as mentioned below:

===================================
Our Freeform Pico range of 3D printers are a single material system which
means you do need to 'break-away' supports by hand after printing. Our
Composer software automatically places these support points in the exact
positions in which they are required so processing is quick and easy.

Asiga_Support
====================================

It's also unfortunate that I don't as yet know of any service bureau that
offers to build parts on one of these machines. Perhaps Shapeways will see
the need to offer a material/process that will reproduce finer detail?

I can see that this is definitely coming, but we're not quite there yet.

Dennis



------------------------------------

Yahoo! Groups Links




------------------------------------

Yahoo! Groups Links




Another Shapeways report

Robert kirkham
 

I've posted a number of photos of my own recent experiments with 3d printing (waiting for them to be approved). These were done by ADC (Advanced Design Concepts) - but as far as I know they use the same machine and substance as Shapeways. Overall I am quite happy with the parts I received.

The first photos show tank car underframes for CPR 389xxx series tank cars. The cars looked a lot like the Athearn single dome tank (and also like an SP prototype Tony Thompson has written about modelling). I've been muddling my way through this project for a number of years, but this is the closest I've come to an acceptable frame model. At this point the issues are in my design errors - not the material or process used by ADC. that said, I can see some grain in the part that may show through the paint. And the particles that are fused to make the part do produce some "noise" when under magnification. But for frame parts that will be largely hidden beneath running boards and the tank itself, I think this is acceptable quality for now.

The other part is an inverted Murphy end used on the CPR's 2975xx series single sheathed automobile boxcars. The rest of the model is still in process. Again one can see some waviness in the flat surfaces, and some imperfections in the corrugations, but overall I think it is a satisfactory starting point for the model. My photography isn't good enough to show the rivets along the edges, but they are there too.

I've been using Bestine rubber cement thinner to clean the waxy stuff of the parts with success so far. A few minutes in that stuff cleans them and changes the parts from translucent to opaque white and cleans some of the wax away.

One thing about ADC - they focus on your job so the parts are oriented as you would like. The auto-box end was modelled laying on the interior side of the model. Interesting that the view of the back shows more of the printing texture. I assume that is the wax support - and "yes" it is far more grainy than any other surface of the model.

By the way this ties into the other thread re the UP boxcars - as, for example, I believe this process allows one to build the ends without hacking up Tichy parts. Of course some of you are skilled enough that you don't hack, but for those of us who do . . . .

Rob Kirkham

--------------------------------------------------
From: "soolinehistory" <destorzek@mchsi.com>
Sent: Saturday, October 13, 2012 1:08 PM
To: <STMFC@yahoogroups.com>
Subject: [STMFC] Re: Another Shapeways report



--- In STMFC@yahoogroups.com, "Rob Kirkham" <rdkirkham@...> wrote:

Curious about the preparation you did on this part before priming Dennis?
Just wondering whether any of the distortion might be the waxy support
material they use? Not that I'm getting completely clean surfaces either,
but thought I'd ask.


Rob Kirkham
That's what I'm wondering, Rob. Hey, I don't have any inside track on this, I just submitted my part file through the automated front end of the web site, like anybody else. I would have thought they would have built the part with the flat disk surface that makes the end of the valve facing up, to give it the best quality, but apparently not. I actually submitted a dozen of these, joined together on a "runner", and I think they built it standing on end. It really doesn't matter, since the purpose of my test is to see what kind of quality can be had on ALL of the surfaces. This is the perfect part for a test, as far as I'm concerned, there is no "show face", they are ALL equally important.

Let me address Dave's comment about "noise". It appears that the best quality surface is the one that is "normal" to the print process, that is, flat and parallel, like a sheet of paper relative to the print head of a ink jet printer. These surfaces will be flat and smooth, as the face of Tom's boxes are. The next best quality will be on surfaces that are perpendicular to the normal, because each layer should end at the same point. The problem is they don't; there are minute differences in both the size and position of each dot of resin deposited, and the result is a certain amount of surface noise. The next worst surfaces are going to be those that are round, or at an angle to normal, because there is the possibility that the edges of the layers will actually show.

I am now realizing that the process used by Shapewys has another pitfall; the basic process can't build parts with overhangs, since there would be nothing to support the first layer of resin that hangs past the previous layer, so the process used by Shapeways builds a wax structure to support this first layer. Unfortunately, it appears that the wax construction is done at a considerably coarser resolution than the actual part, and any surface built against the wax picks up this coarser resolution. Tom pointed this out when discussing a unsuccessful earlier attempt of his, and If I can borrow a link to his photo:

http://www.pullmanproject.com/Shapeways10.jpg

You can clearly see the striations where the part was built against the wax supports that were needed to build the overhanging features. I believe I'm seeing this same effect on the bottom angular surface of the bowl on the bottom of my valve:

http://www.flickr.com/photos/25967611@N04/8077677749/in/set-72157623125645997

I have no idea why they would degrade the resolution of the process by using a coarser resolution for the support material, but it appears they have.

I'm wondering if these fused disposition process (FDM) is ever going to meet our needs. However, I see stereiolithography (SLA), where the part is grown from liquid polymer in a tank, has considerably finer layer resolution. Here's a video of the process. Scroll to the end to see the finished parts:

https://www.youtube.com/watch?feature=player_embedded&v=l2SCrahu2fo

Asiga is a new low cost (relatively) entrant into the field, here is some comments from their discussion forum:

====================================
Our system has two main factors that affect build quality of the parts, these are listed below:

1. Image Resolution
This refers to the size of the pixel in the exposed image. The Pico and Pico Plus39 have a 39 micron pixel size, the Plus33 has a 33 microns pixel and the Plus27 a 27 microns pixel. The smaller the pixel the sharper the exposed image and the higher quality surface finish and detail resolution.

2. Layer Thickness
The thinner the print layer, the less visible the stepping. Our range of printers have presets from 25 microns through to 150 microns and you can select which layer thickness you require depending on the part you are printing. The 25 microns layer thickness will achieve a much better part resolution compared to the 150 microns style. You can also customize this yourself and print in 1 micron increments if you wish.

A combination of these will determine the resolution of a printed part.

Please let us know if you require clarity. If you are unsure which machine suits your application then let us know what industry/product you are producing.

Asiga_Support
===================================

The build envelope on these machines is somewhat limited; 35 x 22 x 75mm for the finest resolution printers. That's 1 3/8 x 7/8 x 3 inches, approximately. Big enough for parts, not for complete carbodies.

Unfortunately, SLA is a single component system, so overhangs require support structures, as mentioned below:

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Our Freeform Pico range of 3D printers are a single material system which means you do need to 'break-away' supports by hand after printing. Our Composer software automatically places these support points in the exact positions in which they are required so processing is quick and easy.

Asiga_Support
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It's also unfortunate that I don't as yet know of any service bureau that offers to build parts on one of these machines. Perhaps Shapeways will see the need to offer a material/process that will reproduce finer detail?

I can see that this is definitely coming, but we're not quite there yet.

Dennis



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Yahoo! Groups Links




Re: L&N and NKP gons and flat--Who is doing the decala and what colors were these cars painted?

Chad Boas
 

Jerry was working on them but I havent herd from him in a while. I am going to use the scrap box and some Microscale letters for the L&N and Microscale MC-4243 NKP Cabooses decale sheet has the small "NICKEL PLATE ROAD".
Chad Boas

--- In STMFC@yahoogroups.com, "gary laakso" <vasa0vasa@...> wrote:

Who is preparing the decals for these cars and what colors were they painted? I checked my sources and found nothing on either the gons or the flat cars.
However, I did complete (weights to be added tomorrow) 9 of Chad’s Great Northern flat cars and they are really well done.
gary laakso
south of Mike Brock
vasa0vasa@...





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