I presume that you have been to the MTH website/Product Locator? I found them listed
as 40.75 inches, A-B-A. The number is 30-, so they are RK, but do not show as
"RailKing Scale", so...MTH, bless 'em for bringing out RK Scale, can confuse us.
Anyway, find a known Premier (20-) or RK Scale A-B-A with the Locator, and compare.
My GM&O A-B-A set was RK Scale, I think, and are as scale as a PW F3, after which they
were patterned.