Truck styles for freight cars - questions

[turbine682]

Hi,

Can anyone point to a specific reference that explains the difference between various freight side-frame styles (arch-bar, andrews, bettendorf, etc.)? Also, (seen in Atlas N-Scale truck) What's the difference betwee 100 ton rollers and friction bearing?

Any other info greatly appreciated....

TIA,

--Ed

[dehusman]

The RPI site has an extensive library of prototype info. Some of it is free, some is to subscribers only. I think its $5 a month. Search for "NEB&W" (New England Berkshire & Western, that's the RPI layout).

The first trucks had a wood beam that sat on the axles. Then they made a frame out of iron (later steel) straps. That's the archbar. The journal box (the part that has the bearing that rides on the axle end or journal) was a separate bolted in piece. There were dozens of designs for archbar trucks. They were used from the 1870's or so until WW1. At the same time there were some pressed steel sideframes, made up of sheet steel pieces, the more well known was the "Fox" truck.
When steel castsng became more common the sideframe was made from cast steel, but it was made to use the journal boxes from the archbar trucks, this type is generally known as the "Andrews" truck. It was used until the 1960's or so.
The next evolution was a cast steel sideframe with integral journal boxes. This was used from the end of WW1 until the 1980's or so.
There are two general types of bearings, "plain" (sometimes misnamed friction) and roller. The plain bearings have a block of brass that sits on the top of the axle end. There is a reservoir of oil in the bottom of the journal box and some type of fiber material (cotton waste or a pad) that wicks the oil onto the axles end. That lubricates the brass block. This is the bearing method used on all the trucks described so far. A plain bearing car will have a journal box and a lid that can be opened so the carmen can pour oil in the bearing to lube it.
A roller bearing uses small rollers to support the axles end. They are commonly sealed bearings and do not need to be oiled. You can identify those bearings because you can see the axle end and on most newer designs you can even see the ends of the axles turning.
The next step was a cast steel sideframe that could hold a roller bearing. In the 1960's manufacturers stopped making new plain bearing trucks and by the 1970's had switched to all roller bearing cars.

Hope this helps.

Dave H.

[turbine682]

Hi Dave,

This helps alot. I also talked with a veteren railroader who explained that friction bearings (those with journals) were eventually outlawed and all were replaced with roller bearing. For model railroading, I understand that it doesn't matter if one uses 100-ton rollers or friction bearing (functionality) - it's just a matter of correct modeling for an era. The other difference (e.g. Micro-trains) is the shank length of the coupler.

Any other info or corrections from all are welcome.

TIA... --Ed

[Anonymous]

Where is this RPI website?

[dehusman]

http://railroad.union.rpi.edu/

[turbine682]

Aia Duhhh.... I just discovered that our store has several copies of .... get this....

The Model Railroader's Guide to FREIGHT CARS (by Jeff Wilson). Gee, amazing that many of my questions were answered by the material found in Chapter 8.

Thanks for all of the previous input... need to check out that site.

Happy Railroading!

--Ed