Even if A.R.A and later A.A.R. tried to standardize the design one can find hundreds of different combinations. Very few manufacturers offered all the parts needed to make a complete box car, hence sub suppliers furnished; roofs, doors, ends, running boards, ladders, hatches and trucks to name a few. This is a brand new release and represent the standard 1937 AAR 40´ Box Car. It is offered with Murphy raised panel roof, both Youngstown and Superior doors and the most common 4-5 Dreadnaught ends. AZL also offer the correct choice of wooden and etched steel Running Boards. This enables AZL to offer a very prototypical Box Car. Some small notes on freight cars in general. Trucks used to be bolted together and that was outlawed by A.R.A. / A.A.R. for good reasons. A maintenance nightmare since they could come apart. Replaced by solid frame trucks they also saw a change as A.A.R. made roller bearings mandatory in the early 1950s. Other developmental changes effected the running boards. They were probably all wooden to start with. Wood was more slippery than steel, so wood was banned in 1944. In the 1950s running boards and side ladders were outlawed as well. That is why the 1930´s Box Cars lived long with updates through their operational lives. By 1970 these Box Cars could not be found on Class 1 railroads any longer.