The online magazine on the history and operation of vintage scale model trains in American OO gauge

Wednesday, July 1, 2009

Rio Grande Models Sn3 trucks for OO

One other maker of Sn3 trucks is Rio Grande Models. I purchased two of their designs, a 4’ 6” caboose truck (arch bar) and their version of the Andrews truck seen in the below photo.

As with the PBL trucks the sideframes scale out pretty well for American OO due to a quirk of scales and gauges. In fact, I would rate their Andrews truck as being even a bit better looking in OO than the PBL version. However, it is not completely clear to me how they intended these to be built up even in Sn3. My guess is that you are just supposed to clamp and glue the parts together after the wheelsets are in.

The big thing for an OO conversion is to figure out a bolster that holds the axles very square. It would be a pretty simple matter actually with a drill press to drill out a new solid bolster with holes on each end to fit that sideframe pin, similar to the design used on some Nason and Graceline trucks back in the day. Get it all good and square and it would work. Another option is to cut the existing bolster and insert it inside a square plastic tube to extend it to OO width. The option I tried, seen in this photo, was to make a new bolster from Evergreen 3/16" square styrene tube. I cut it very square in my trusty Miter Jr., clamped it all square with the wheelsets I chose in place (NWSL 20” On3 wheelsets, just a hair underscale), dropped on some super glue and let capillary action do its work.

There may be a better way but in any event this is one way to do this conversion and both pair of trucks look like they will be solid and reliable runners. This is for sure yet another truck option for American OO use today, as seen on this small tank car (converted from a large HO car some years back) before painting. Click on the photo for a larger view. The car on the right, for comparison, is Scale-Craft.

The caboose truck was also built up in the same manner and was going to be used on a vintage Nason caboose. However, the trucks don’t match up well with the screws and bolsters on this car (the screws are at an angle), which is a bummer. I will save them for some other wood caboose in the future.

[A theme of a couple of these truck posts is that I need to get a small drill press. I better start shopping…]

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