Took measurements of all larger scale engines for distance between lead truck front axle and rear bogey axle for required length of TT bridge track. Thought about this, decided to list for others to have for their info in quest for correct TT for current or future motive power units. Hope this is of use to others and save time/money when matching TT bridge and wheel arrangements.
St Fe Northern 3751, 3rd Rail 26in U.P. Challengers Lionel 29in U.P. Big Boy MTH 33in S.P. Cab Forward 3rd Rail 28in E8 A-A units K Line 33in Erie FM A-A units Atlas 31in NYC Niagara 6024 Lionel 27in E6 A-A units MTH 33in S.P. GS4 4410 Lionel 26in StFe YB3 1795 Lionel 26in U.P. FEF 8444 Weaver 27in F3 A-B-A Lionel, MTH 36in GN 4-8-4 2558 3rd Rail 25in NYC Vandy Hudson Lionel 24in St Fe PA-PB 2000 Lionel 30in U.P. Propane Turbine MTH 31in Veranda Turbines #73,#75 29in T&P 4-8-2 #907 Lionel 24in
The TT bridge track measures a tight 28in, so it is good for most motive power. Half of my larger engines fit this, only need to add 2.5in on each end and all steam power fits on TT bridge. There are "prototypical" examples of this for upgraded TT to handle larger steam by many railroads. On some, the additional rail lengths were attached as needed and then elevated to clear the whisker tracks until aligned.
Jesse TCA 12-68275