[Brian Considine]

Just to add that in my experience most of my G1 locomotives,when running on analogue trundle round at a nice scale speed with a setting round about 10 - 12 volts so you would only perhaps have a problem if the layout was extensive and/or badly wired.

On DCC I use a Lenz LH100, set to 22volts, but I don't see any reason that any of the other units on the market would not do the job, provided that there is enough power available.