The radius you've got is going to limit you to something like a Shay, Climax, 0-4-0 or perhaps an 0-6-0. Any steam engine with a larger wheelbase than that probably can't make it around that curve. I have Bachmann 2-6-0 and 2-8-0 engines and can tell you that they require a larger radius than you have.
When you say "similar in steam", if you are referring to live steam, an Accucraft Ruby will do R1 radius. I have a the same problem with restrictions due to a small radius loop, which would be very labor intensive for me to covert to R2. If you have an option, I'd suggest doing away with the R1. I have an Aristo Craft U25-B that will negotiate the R1's traveling West, but not East. But even traveling West, can not pull more than a few cars. GP30, GP7, 2 truck Shay, and Climax do the R1 with no problem. I can't even think of running a 2-8-0.
Good Luck,
Stack
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