A scale S2 turbine is a BIG engine (30" long) and requires O-72 curves, at least the Lionel and 3rd Rail engines do. MTH has not made a scale version. If a scale version works on your layout, I recommend getting one. Once you see the scale version, the different sized semi-scale versions from MTH, Lionel, K-Line all look weird, at least to me. Here is my 3rd Rail.
By the way, 3rd Rail's model is actually a Williams product. When Jerry Williams retired, this model was still at the factory. Sunset Models bought them (not sure of the agreements) and sold them as their first 3rd Rail product. It is a nice engine once you fix some minor issues, but turned out to be expensive by time I upgraded it with ERR and other goodies. In hind site, I should have gone with Lionel's TMCC version.
