At 1:20 scale the Bachmann Porters (either one of them) has a wheel size of approx 27" Not far from the 30" of the #3 and #5 loco's your after. If you drop to 1:22.5 that wheel size increases to 30" anyway! At 1:20 the Porter's wheels are good fro Marsh anyway.
Axle setout is 70mm, or 56" at 1:20, or 62" at 1:22.5.
Hope this is useful.
David, that is exactly why I bought the porter, for its close wheel base to #3. I saw an MLS member start a forney with an old side tanker and a Lionel cab, but he never finished.
It also featured as a finalist in last year's Garden Railways photo comp (GR December 2004 issue).
I remember seeing that model in GR. He had a consist of scratch built GR cars. That was a good looking model.
Maybe I'll try to do the porter challenge. Thanks for the info, David.
Edited By Colin on 1127682726