Construction of new 36' cars lasted from about 1890 to the 1910's. By the early 1920's most new boxcars were 40' long, although like the earlier 36' cars they were normally 8-1/2' high. The 40' long - 10' high "standard" boxcar didn't come along until 1936 or so.
Freight cars with arch-bar trucks and without steel underframes (that is, having wood substructures and truss-rods) were banned from interchange service in the 1930's. Many 36' boxcars at that time were old enough that it wasn't worthwhile to add steel underframes and new trucks, so many were scrapped at that time.
As for reefers, however meat packing plants had been built 100+ years ago with door openings in the walls spaced to serve several reefers at the same time. Because of that, shorter than 40' reefers continued to be used in meat service into the1960's.
If you want combined shipping, please purchase all your items in one order. If you purchase items in more than one order, send us a message so that we know about the additional items and box the orders together. (When items are bought in multiple orders, we do not always notice they were bought by the same person unless we are notified by the buyer.) We refund extra shipping charges when combined shipping is requested. If we ship items separately, we do not issue a shipping refund.
For our international customers: YES!! we do combine shipping. The most economical way for you to buy multiple items from us is for you to send us a list of the items you want to buy. Do not purchase them as they are listed!! (This leads to higher than necessary fees & shipping.) Send us a complete list of all the items you want. Then we will cancel the listings for the items and turn them into a special listing just for you (We'll send you the listing named before making it active). It will have your full purchase with the correct shipping box size and weight. This saves you on the international fees & shipping.