Fixed a mistake in my post...the 4-8-4 611 had an 11.1v LiPo battery pack installed, not 9.6v, but changing it to a 12v did up the speed from 48mph to 54mph.
Most of my other engines use a 9.6v battery and run fine.
Ted S, I agree with the comments you made about top speed, 45 (maybe 60 for a fast passenger engine) is fast enough on a home layout.
Although the gearing didn't change, the 3 engines in question are the smoothest running engines I have at low/slow speed. I think the gear ratio in the Williams 4-8-4 was around 40:1 last time I checked.
The voltage used by the Deltang receiver has to be low, it's such a small package there's no large components on the board.
I want to say that 12 volts, whether it's from a transformer or battery, is the same but I really don't know for sure.
I could put a larger battery in the 4-8-4 with that huge tender, but I see no need. I think the motor in the 4-8-4 is the same as in the other Williams engines I have (two 2-8-2 and two 4-6-2). The 3rd Rail E7 has a big 12v Canon motor while the others are MTH and Atlas and all have a smaller motor(s) in them.
