C-D-S offered dry transfers for those roads (usually specific to particular cars - the C-D-S catalogue shows four sets for CNJ steam locos, another four for diesels (early-to-mid '60s), two for passenger cars, one for a service combine, four different ones for boxcars, one for gondolas, two for open hoppers, six for covered hoppers, and three for cabooses.
Except for the diesels and the service combine, all lettering sets are suitable for pre-60s.
This is the only CNJ car I have, the first one too modern for my '30s-era layout lettered with C-D-S…

…and the same car, re-lettered with a different, more era-appropriate, C-D-S set…

For the Reading, the catalogue shows one set for a steam loco, four for diesels, one each for passenger and head-end cars, and four for boxcars. All sets except three of the ones for boxcars are suitable for the pre-'60s era.
Here’s one of the Reading sets on a Train Miniature car…

C-D-S is no longer around, and their excess stock and artwork was bought by Ozark Miniatures, although I don’t know what, if any, they have in-stock. There was some talk of eventually re-releasing the catalogue as decals, but I don’t know if there’s been any progress on that. I did buy some former C-D-S alphabet sets from them, re-done as decals, but the ink was not very opaque, especially as compared to dry transfers.
C-D-S sets turn up quite often at local train shows, and I’m speaking of major amounts, not a few dozen sets.
I much prefer dry transfers over decals, but many folks don’t, as yo