What do you mean by 0-48 and 0-54? Generally in 3 rail when they mention 0-xx, it means xx diameter, not radius. e.g. 0-48 is supposed to be 24 inch radius which is very tight for 2 rail.
In 2 rail we generally just refer to curve radius without the "o". so 48 inch curves generally means 48 inch radius curves or 96 inch diameter for a turn back. and I think many of us measure center line to center line.
48 inch radius by the way is a very workable curve for 2 rail. It is sharp by some standards, but most equipment except modern long (70-80 ft) freight cars will go around it. Also most cars can be modified on the underside to make the curve. I have run full length Walthers pullmans on 48 inch radius. Just keep the underside details clear of the truck swing. It does not look the best but works.
I think any 4 axle diesel model with easily hand 48 inch radius and sharper. Steam engines up to medium size generally do. I have a Pennsy USH mikado with all wheels flanged, and it will do it, but it has to be laid smoothly. 6 Axle diesels will often do it but you have to test them. A lot of the new stuff from MTH in 2 rail probably does. I have some Sunset E7s and they do.