Would I be right in assuming that 33" wheels are the standard for everything other than hi-cube boxcars these days? I need to buy quite a few replacement wheelsets and don't want to get this simple detail wrong!
Modern Freight Cars - basically if the capacity is 77 tons or less, the car uses 33" wheels. If it is over 77 tons capacity, 36" wheels are used. 125 ton capacity cars use 38" wheels. Most box cars are in the 'under 70 ton' range and use 33" wheels. You will need to look at the CAPY printing on the side of the car or consult an equipment register to get that information. Most new gondolas and tanks cars use the 36" wheels, as do covered hoppers. Auto Racks many times have 28" wheels for clearance reasons.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin