GRJ's reply to my question about why Magne-Traction isn't used more extensively make alot of sense.
TED S posted the fact that trains ran just fine before Magne-Traction.
I know from experience that my oldest Lionel locos, the ones made between the end of the war up to just before Magne-Traction was implemented, do not pull as well as the identical locomotive equipped with M-T.
So the next step, in my mind, would be to add weight at the factory. Isn't that what gives locomotives in the real world the power pull heavy trains ?