That's 10.9 mph with 10 cars vs 6.6 mph with 20 cars
This one appears to use less power (313mW to go 6.6 mph vs 413 mW to go 6.08 mph, each with 20 cars).
It can move the train a little faster, and consume 25% less power.
But... the speed variation is greater when you change the load from 10 to 20 cars:
10.9 down to 6.6: a 40% drop,
vs 8.58 down to 6.08: a 29% drop.
I would argue that the newer rewind, when compared to the earlier one, is making the classic
"trade" of rpm for torque. It can run faster and use less power, but it slows down more under load.
Interesting.
I sure am glad you are willing to rewind these armatures. We are learning a lot by somebody doing it,
and I would not do it.