Large Scale Central

Power calculation

My name is Rick Lucas, I am interested in starting a large scale railroad. I have a question that I have taken to my local hobby shops with no answer. How can I figure out how large of a power supply is needed for what amount of track. For example if I have 500 feet of track how large of a power supply will I need? I would be looking at a minimum of 2 locomotives with cars as well as lighting for signals and other accessories. Any assistance would be greatly appreciated.



Track length has little bearing on the size of power supply you need. What does are the type of locomotive and additional power drains (passenger car lights, signals, sound, etc.) you want to use. Typically a starting power supply will run from around 1 amp to 3.5 amps. Voltage for G scale runs from about 18 to 24 VDC.

Since you intend to run at least two locomotives and you didn’t specify what type, buy a 10 amp power supply. It will have more than enough power for whatever locomotives you intend to run and any additional lights, sound and signals.

There are several choices for power supplies in this range (Aristo Craft, Bridgewerks) and even more if you are willing to look outside the traditional railroad company sources.

Some of these can be used with both the usual style rheostat control or RC control.


For the newer engines with electronics on board (Aristocraft, LGB, USA) you need a power supply with constant voltage control. The Aristocraft Elite will do this, the Ultima will not. Newer supplies will hold the voltage whether at no load or full load. The Ultima 10 amp output will drop under heavy loads and get a ripple, the Elite will not.

Other power supplies from other mfg’s may do as well as the Elite or even better, but I personally would not settle for less than what the Elite can do.

After sel;ecting a power pack, now you need to select how to get power to your engines, throttle controls hard wired between the power pack and track, R?C track power, or RC in the engines.

All this and assuming by your question that you are commiting to track power, not battery power.

Welcome Dan!!!

Using Stainless track verses Brass is also a consideration that should be addressed.