Running dissimilar engines

I wonder if you run two engines together that usually run at quite different speeds if you will damage either or both engines. I have an old Chessie U25B and a new C&O U25B with the newer slow engine. Neither has traction tires. The older Atlas Nscale engines were made before they used the scale speed motor which is now used. Can one of the older/faster engines be run with the newer slow speed engine? I have tried it and they do run together without jerking but it was only for a very short time. I was afraid to try it any longer.

This should be ok, the trick is to run the faster loco next to the cars and the slower loco at the front, as this way the weight of the cars will slow the second loco down and stop it from snatching at couplers. If you have DCC there are ways to tweak the decoder settings to make two dissimilar locos behave identically, though I’ve not had to do this. Hope this is of help!

Thanks. That makes a lot of sense.

Being a technician, I would not run dissimilar engines together. One will always try to become the other and both will draw more current. I would insert a low value resistor in series with the faster motor to slow it down to the slower. The exact value can be found by experimentation if you do not have an ammeter and a voltmeter.
Bruce in the Peg