Proto track and wheel standards...was Re: Re: A very short intro and a heckava lot of questions...


Mike Brock <brockm@...>
 

Tim O'Connor responds to:



It looks like the Proto:88 wheelsets are best route to go.
With:

Rich, if you use that terminology you're going to confuse the
Proto:87 modelers!
Not only them...but a few others as well.

The Reboxx and other .088 profile wheels are
not prototypical -- they are NMRA RP conforming wheelsets.
Well...like Dennis Storzek notes...I don't think this is totally accurate. I haven't found a "code 88" wheel yet that conforms to the NMRA RP-25 code 88 wheel. The term "code 88" [ an NMRA term ] refers to the width of the total wheel...flange plus tread. At least some wheels appear to be code 88 treads [ RP-25 width of .063" ] with code 110 flanges. Such a wheel will operate successfully through frogs built to NMRA Track Standard 3.2 as long as the frog is less than that associated with a number 10 turnout. As the distance between the point of the frog to the wing rail increases...and it does as frog numbers increase...the distance that the wheel's tread must travel to find the wing rail for support increases. A wider tread permits the tread to reach this support sooner than that of a more narrow one. Track flangeways built to NMRA Standard 3.2 are designed to accomodate the wheel tread of a code 110 wheel. The so-called code 88 wheel [ with code 110 flange ] will present a more accurate appearance with its more narrow wheel tread but when a more accurate sized turnout is used, the wheel will fall into the gap between the point of the frog and wing rail. Note that a number 10 turnout frog...larger than probably 99% of those used by modelers...is too small for prototypical mainline function and is primarily of industrial siding size. The frog sizes for the turnout at Dale Jct on Sherman Hill are number 20.

I should note as well that there might, indeed, be real code 88 wheels being produced. I would use them on frogs built to NMRA S-3.2 with concern.

Tim continues with:

Proto:87 wheelset will not run on NMRA standard trackwork.
Tim probably refers to NMRA Tracdk Standard S-3.2. The NMRA has a track standard for Proto 87...S-3.1 and wheels built to Proto 87 standards will run on track built to such standards.

Mike Brock


Anthony Thompson <thompson@...>
 

Mike Brock wrote:
The frog sizes for the turnout at Dale Jct on Sherman Hill are number 20.
I remember reading about an SP track improvement program, in which No. 16 crossovers in Nevada were being replaced with No. 20. This is a little beyond what most modelers can or will do <g>.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@signaturepress.com
Publishers of books on railroad history


Andy Carlson
 

Yes, High Speed cross-overs are large numbered
switches, but keep this in mind- most switches in use
are not High Speed cross overs but regular switches.
Check out frog ratios when you next visit some real
trackage. Simply pace out 10 large steps, then measure
the divergent gap with your same step. You might find
that prototypical switches are mostly closer to # 8s
than 16s or 20s. We had a yard in So CA which had # 6s
until it was removed.

Our biggest deviance from the real railroad is in our
track radius.

-Andy Carlson

--- Anthony Thompson <thompson@signaturepress.com>
wrote:

Mike Brock wrote:
The frog sizes for the turnout at Dale Jct on
Sherman Hill are number
20.
I remember reading about an SP track
improvement program, in
which No. 16 crossovers in Nevada were being
replaced with No. 20. This
is a little beyond what most modelers can or will do
<g>.


Miller, Andrew S. <asmiller@...>
 

In fact such turnouts will not work at all under NMRA stds even if you
had the space, time, talent, and inclination to build one. The points
would be so long that they would get bent by passing locos and the frog
would be so long that wheels (even code 110 wheels) would drop right in
- even the wheels of steam era freight cars. To overcome these
problems you would have to use hardened steel points and fine scale
stds.


regards,

Andy Miller

-----Original Message-----
From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On Behalf Of
Anthony Thompson
Sent: Friday, March 17, 2006 1:31 PM
To: STMFC@yahoogroups.com
Subject: Re: Proto track and wheel standards...was Re: [STMFC] Re: A
very short intro and a heckava lot of questions...

Mike Brock wrote:
The frog sizes for the turnout at Dale Jct on Sherman Hill are number
20.
I remember reading about an SP track improvement program, in
which No. 16 crossovers in Nevada were being replaced with No. 20. This

is a little beyond what most modelers can or will do <g>.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail,
thompson@signaturepress.com
Publishers of books on railroad history




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