Re: Atlas '32 AAR Box - trucks


Eric Hansmann
 

I had some time to check the truck situation on the new HO scale
Atlas 1932 ARA box cars. I had changed the couplers to Kadee #58 on
some cars as one step in an upgrade process. I replaced the trucks on
one car with a pair of the 50-ton Buckeye trucks from Tahoe Model
Works. They seemed to fit fine and the couplers looked to check
against a height gauge properly. But something seemed odd. The
replacement trucks could shift a bit on the mounting screw, where the
Atlas trucks only pivoted and did not shift. The Tahoe trucks seemed
to wobble on the attachment point. I removed a Tahoe truck for a
closer inspection.

Atlas uses a shouldered screw to mount their trucks with the shoulder
depth the same as the thickness of the plastic in the Atlas truck
bolster. The hole in the Atlas truck bolster is also smaller than
that in the Tahoe truck. There is a slight depression or chamfer in
the top of the Atlas truck bolster for the car kingpin to sit in.
Atlas has also designed a stabilizing system on one end of the car
that has two fingers on the car bolster on either side of the
kingpin. These point downward and seem to strike the truck bolster to
prevent too much rocking.

I installed both Atlas trucks and checked the coupler height again.
At first glance it seems fine, but upon closer inspection the car
sits just a little low. The top of the car coupler was just below the
top of the coupler in the Kadee coupler height gauge. I did not have
anything to measure this difference, but it seemed to be about the
width of fine brass wire, maybe 0.015" or 0.020". I removed the Atlas
trucks and reinstalled the Tahoe trucks for another comparison.
Paying more attention this time I noted the top of the car coupler
was just a touch higher than the top of the coupler in the Kadee
coupler height gauge. Again, it was slight and a similar amount of
difference higher as it was lower with the Atlas trucks. I then set
the car with the Tahoe trucks beside another similar car with the
Atlas trucks. The box car with the Tahoe trucks was noticeably higher
as it sat next to the same Atlas box car with Atlas trucks.

I had a set of Accurail AAR trucks nearby, so I ran the same tests
the Atlas 1932 ARA box car. The coupler and car height
characteristics were similar as to when the Tahoe trucks were
installed.

There were a couple of other points I found. Many modelers here use
the center ring of a Kadee coupler box to use when attaching trucks
to a freight car. This piece fits like a sleeve over a 2-56 screw and
it fits inside the truck bolster hole of many typical HO scale model
trucks. This sleeve tends to reduce the amount of play the truck has
on the mounting screw and limit how far the screw can be tightened.
The Atlas truck screw does not fit into this sleeve, nor does the
sleeve fit inside the Atlas truck bolster hole. Additionally, the
shoulder on the screw Atlas uses to mount the trucks is deeper than
the thickness of the plastic in the truck bolster of the Tahoe and
Accurail trucks. The screw supplied with these Atlas cars will not
hold a replacement Tahoe or Accurail truck snugly to the car.

How to fix this? I did not have enough time this evening to do
intensive work on an Atlas 1932 ARA box car. It seems a portion of
the kingpin on the car bolster needs to be removed so a replacement
truck can sit at the right height. That height difference noted at
the coupler check using the Tahoe or Accurail trucks would be the
amount to remove. Secondly, a new hole would need to be drilled and
tapped to accept a 2-56 screw to fasten the replacement trucks. The
underframe of these cars are metal, at least it is metal at the car
bolster.

Of course, this is only needed if you need to change out the trucks.

Has anyone else made any notes, or have any suggestions, to ease
truck replacement on these cars?

Eric Hansmann
Morgantown, W. Va.

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