To add to what AUSTIN BILL stats above, Sunset/3rd Rail has produced prototypically accurate models of steam locomotives that neither Lionel nor MTH would even touch! For example, models that I already own:
1) CB&Q 4-6-4 Hudsons, all three versions. CB&Q 4-8-4 Northerns, two different versions, three different road numbers. CB&Q 2-10-4 Colorados, both versions with different road numbers.
2) Northern Pacific A class 4-8-4 Northerns, three different versions (I have the A4 with the big pedestal tender). NP Z class Challengers, in two different versions, and various road numbers (I have the Z8).
3) Southern Pacific MT class Mountains in 3 different versions, with various road numbers (I have the MT-4). SP P class Pacifics, in various versions in various road numbers (I have the P-10 with the skyline casing). SP GS-4 Daylights in various versions and road numbers (I have the black version with removable skirts). SP 4-10-2 3 cylinder SP class, in two different road numbers (I have #5021). SP AC-9 2-8-8-4 in both coal and oil (haven't saved enough money for THAT one yet).