Atlas sets the bar for intermodal equipment being 1:48 and prototyipcally accurate. Just keep in mind that their offerings are late-80's era stuff. Their containers are fabulous, but most of the 40ft containers on the rails today are high-cube.
The original Lionel notquitescale offeriings had awesome 48 ft containers with very prototypical markings. Then they started making 48ft evergreen and 48ft Maersk, containers that have never existed. Their stuff is early 1990s.
No manufacturer makes anything like you would use to put together a modern intermodal freight train. You have to go to HO or N scale for that.
But I agree with David above. Atlas first, Lionel second.