On May 27, 2013, at 11:27 AM, Steve Sandifer <steve.sandifer@...> wrote:

The change from A.T.& S.F to A.T.S.F. took place in 1938
The change from A.T. S. F. to ATSF took place in 1944
Just because the lettering changed does not mean they swapped to shorter boards. I have seen photos of ATSF on long boards.
Trucks: "Bettendorf" type cast steel

Steve is, as usual, correct, though it is worth noting that these changes were usually not made until a car was repainted, which was often several years (and sometimes many years) after the change went into effect.

Trtucks on all of the stock cars built by the Pennsylvania Car Co. in the late '20s were ARA cast steel with spring planks and Barber lateral motion devices. An exact HO scale reproduction is Tahoe Model Works' TMW109 (110wheels) or TMW 209 (88 wheels). See my model truck presentation at <https://docs.google.com/file/d/0Bz_ctrHrDz4wMkpBYUw1RjhmRkE/edit?pli=1>.

Richard Hendrickson