Lou1985 posted:I like the Pittmans more than other can motors. I find them smoother at low speeds with much more torque. I've got a buddy with a Legacy GS4 from 2016 with a Cannon motor. We've done a test between his Legacy GS4 under Legacy control and my Premier GS4 (PS1 converted to PS2 3V with a 9434 Pittman) under DCS pulling the same 8 car passenger train. The train is 8 Lionel 18" aluminum passenger cars. My GS4 will start the train at a lower speed with less current draw (starts moving the train at 2 scale mph and can run at that speed without stalling) than his GS4. The Legacy GS4 manages to get down to around 5 scale mph. Mine with the Pittman is noticeably smoother as well.
Not calling B.S., but a video of this comparison test would be instructive. Norm Charbonneau's video shows the new J3a starting a long passenger train smoothly and without difficulty. I've done many tests like this over the years. Electronic speed control covers a multitude of sins: poor motors, poor gear ratio, etc. A better test of the motor itself would be to repeat the experiment with speed control turned OFF, or even disconnecting all of the electronics, and running both locos on straight DC.
With a load like that, the mass of the train masks any potentially jerky operation. Another test of performance is running the loco and tender "light," especially from tangent track into the minimum-rated curve. Nothing ruins the illusion for me like a dramatic slow-down, or laboring due to the sudden increase in friction when entering a curve. This is where I've found that the gear ratio becomes important.
When you're talking about starting a train with the slack stretched, the stall torque of the motor is important, but so is the diameter of the worm wheel. If you think about how the worm and worm wheel interact, the radius of the worm wheel acts like a lever arm; the longer the better! I know the MTH 20-3047 Niagara had a much larger worm wheel than the 20-3020 Premier Hudson, and exhibited better starting characteristics with an identical motor. Perhaps your GS4 uses the Niagara setup?
Lionel's venerable 700-series Hudsons also have a very large worm wheel that was often re-used by scale modelers of the 1940s in their scratch-built brass locos. For this reason, a Lionel 773 refitted with a can motor would probably have better starting characteristics than many other models. But its 18:1 gear ratio isn't really that low for a scale loco with large drivers. I've found that even the big Pittman motors aren't happy below 800 RPM. So the Hudson might struggle to run consistently below 10 mph. Newer models like the 1990 Williams USRA Pacific (geared at 44:1)! would be smoother drifting around the engine terminal at walking speeds. Again all of my observations are WITHOUT speed control. Good topic!
