I have adapted Walthers passenger trucks to a variety of rolling stock. Those bolster screws are, of course, designed to contact two metal strips set into the floor of the car for lighting, which precludes using any usual cross-wise bolster.
Usually what I do is fabricate a length of "center sill" using appropriately sized styrene, in most cases 3/16" square and sometimes add an additional strip of .080 or .100 x .250 between it and the floor. Check the necessary thickness for floor height and best coupler height.
Here's a brass PRR car I did just last week:
PRR_POC70Rb by Edmund, on Flickr
Once I have the length of the center sill required I'll mark the center point of the truck pivot. At this point I add a short length of 3/16 styrene tube with another piece of 1/8 tube cemented inside. Allow plenty of time for cement to cure.
Centersill-parts by Edmund, on Flickr
This matches the unusually large bolster hole that Walthers uses on their passenger trucks. Then screw in place with a wide-washer head screw or, as in the photo, a screw with a flat washer.
PRR_POC70Rbolster2 by Edmund, on Flickr
In the view above, the center sill is shown epoxied in place and screwed from the other side of the floor using small, coarse-thread screws.
PRR_POC70Rbolster by Edmund, on Flickr
PRR_POC70R by Edmund, on Flickr
Hope that helps, Ed
I recently bought a pair of Walthers 4 wheel Commonwealth heavyweght passenger car trucks as well as a pair of 6 wheel, Pullman 2411 heavyweight trucks. I need to mount them on old Walthers stamped steel cars of the 60's and and an old Rivarossi heavyweight diner. Most of my 60's era heavyweights ride on Central Valley trucks that are no longer made but fit quite well. Is there a way to mount those trucks without using a jillion spacer washers to get them to sit properly and have the couplers at the correct height? It appears to me that the screws holding the sideframes to the bolster are way too high for the car's body bolsters and the screws scrape the car floor. The 4 wheel truck comes with an alternate bolster, but the mounting lug on the bolster itself still is way too low. Am I missing something here, or do I need a boat load of spacer washers?