Question for GunRunnerJohh and other Technocrats

I'm no technocrat. However,  for starters, in the case of Lionels legacy  offerings. They have "back drivable" gears, which allow the slower engine to coast more easily.

Many times you'll see an admonition for TMCC stuff that lash-ups may not work with cruise on, that's because they will indeed fight if they don't have the same speed curves.  With cruise off, the slightly slower locomotive will simply get pushed a bit and reduce the load on the motor, hence it will keep up with the rest of the consist.

Hook an old Atlas EOB equipped locomotive and a Lionel Odyssey 1 locomotive with cruise enabled on both, and you'll see what happens when the speed curves don't match!

I made a video years ago of several MTH engines spread out all around the basement pulling and pushing on my 2 rail layout. Because they monitor the flywheel, when they're working together they help each other actually run smoother as a team.

 The surprising thing to me, was I could place my hands on top of the cars, and play with tension in the train while it's moving. If I held it back slightly, engines would compensate ever so slightly. The same thing happened if I pushed. Nothing derailed even with tiny wheel flanges. It's like they could sense the train's tension.

 Now outside things are on a bigger scale. They are G scale in my backyard. The weight of the train climbing grades is really amazing. I can barely move a 100 car train up a hill by hand for example. The engines really are doing major work in their scale way. If one quits or stumbles, you'll see it right away. If the right amount of power is spread through the train, it will run smoothly up and down hills all day long. Each engine joins the team and helps in it's own way.

Multiple locomotives in a consist do not have to be perfectly matched in speed in order to run together. A "faster" locomotive will pull in the train slightly harder than a "slower" locomotive, but they will run together just fine.

The key word being "perfectly".  If they're grossly mismatched in speed, it's another story, especially with cruise enabled.

I was thinking that, because a locomotive's wheels are not free spinning, like a non-powered car, the variance in speed would put a strain on the faster locomotive, because it would be pulling against something that is giving resistance.   Thanks for the explanations.  

Peter

That wouldnt apply  for a mismatch set of PW F3'S motors would it?  

oldtimer posted:

That wouldnt apply  for a mismatch set of PW F3'S motors would it?  

Of course it would, or was that sarcasm   I am pretty sure the PW Repair Manual had an adjustment procedure with brushes, thrust washer and such  to balance the motors.  But again with small tolerance differences it is not something the motor can't handle, whether AC motor or DC can motor.  G

I believe this one fact alone, as Engineer Joe and others said, is the answer: speed of each engine is constantly monitored and the electronics keep them at the same set speed, regardless of engine size, power, etc. The only exception would be if the wheels slip.

Similar situation: Look at any highway full of cars traveling at 70 mph, for instance. There are semi-trucks, pickup trucks, SUV's, cars pulling boats, small and large cars. All of these are different, some have a much larger power-to-weight ration than others, and yet they can all maintain the same speed. Why? Because the drivers are constantly monitoring their speed, or use the cruise control to achieve the same result. The cruise control works in a similar fashion as our model engine speed controls.

Just my 2-1/2 ¢

Alex