I've returned to these kits after many years of letting them sit on the shelf, and am starting to enjoy the project of building them. Of note - no distortion of the pats sitting in my basement all that time! Most are the old very dark grey resin, which had its issues, but my project is moving along smoothly enough so far with 7 bodies built except underframes/floor castings.

However, as I work on the cars I keep comparing them to other similar models on the market and to prototype photos, making changes as seems right. Being a long lived group of cars that were built and re-built, it is tough to follow all the permutations - even with numerous magazine articles as resources. So while I've scanned high and low, I have not managed to find any proto photos that explain the underframe design on most of the kits.

The underframes in question have straight cross bearers (or what ever they are officially called). These straight cross bearers are fabricated, but resemble I beams. Their ends protrude below the car side sills several scale inches - especially the larger two in line with the door posts.

In contrast is one underframe casting that has the cross bearers frame sections with a tapered shape such that they connect to the inner side of the side sill and are not visible below the car side. This latter version seem prevalent in all of the photos I've looked at.

So my question: What cars (number series) do the straight/exposed crossbearer underframes match with? Did these last in service with this frame design into 1946? Or do I need to modify the frame design to match the cars with tapered section cross bearers?

Thanks in advance

Rob Kirkham