Once upon a time, there was a fantastic topic about all the different intermodal items made for O gauge. Unfortunately, it accidentally got deleted about five years ago. It had all the details of which containers fit in which cars. The person who gathered all the data and started the topic, has since left the forum.
Having examples of almost every different intermodal item ever produced, in my collection, I suppose, if I was feeling ambitious, I could take the photos and do the research to try and recreate what was lost.
As for the OP's question, 40' containers were made by a number of manufacturers, Atlas, K-line and Right of Way. I'm not sure if Weaver ever made any 40's, but they had 20's which are now being made by Atlas. A new entry in the 40' arena is Menards. They actually seem to have found and reproduced the old Right of Way well car, and make containers for it. They are now selling just the containers without the car. These were announced in just tha last couple weeks.
45's are just made by Atlas as far as I know, and I think the MTH's are 48's. Atlas started doing the 53's a few years ago.
Lionel just did a batch their "scale" cars, but I haven't really examined their dimensions. All of this stuff was in that lost topic, except for the newest additions, which was why it was such a loss to the forum when it got deleted.
