What is amperage draw on a Williams 4-8-4 Southern Pacific (#4449)

I believe a key to knowing what any engine draws, is having it at a set voltage. If it's running below that, the amp draw goes up.

I run my outside layouts at 24 volts to keep the amp draw low. The engines see around 21 volts at the board inputs.

You could find some listed value, and it might not apply here if you're running below the stated voltage.

So what is your power supply? (and what is it set at if adjustable?)

How big is your wire? How is it connected to your rails?

This is your decoder specs. Run it higher voltage!

Thank you very much for the help. The power supply is 18V 4amp DC.  Its not my loco, so I can't see the thickness of the wires. I assume the thicker the better is the general advice?

Which version do you have? The scale brass version or the "semi-scale" diecast metal version?

I believe it is the diecast metal one

I think you're getting better help now than from me.

Just to finish, the wire matters and so does everything in the chain. You can have a great power supply. If the wire, track connectors, etc., aren't the best, the power won't get there fully. So it does matter. When the amp draw goes up, it matters even more.

I've seen posts where someone used old thin telephone, doorbell, or furnace wire. It may work. It won't deliver full power in larger scales to the engines. When more things are on the rails, it gets worse.

I like to read that the power is 18volts 4 amps. Now the thing is..... is the board getting that fully?

@3RaylFan posted:

Thank you very much for the help. The power supply is 18V 4amp DC.  Its not my loco, so I can't see the thickness of the wires. I assume the thicker the better is the general advice?

I like #14 stranded pure copper wire for track power runs.

So if this is the semi scale diecast engine it is the latest version from Williams that was set up to run from the factory on AC power with a reverse unit, smoke unit, whistle and bell????

So I guess all the Willams parts the AC board, smoke unit and sound system has been removed to install the SoundTraxx decoder to run on DC power?

Not sure if this helps but I bought a new in the box Williams Semi Scale GS4 SP 4449 just before Christmas for my Grandson, thus assume it is the same engine as yours.  Just a few days ago had it home to check on an issue, tightened some screws and he has it back in action. When I went to test it on a loop of track I have set up with the Lionel basic 30 watt transformer it tripped the breaker and would not run on this transformer. I had to use the Lionel CW80 80 watt transformer to run it. I assume you have the smoke unit disconnected. This motor is large and seems to draw a lot of amps. Is it possible that the motor is binding at all causing the board to trip?  On your engine if the same as the one I just bought; the motor flywheel is in the cab of the locomotive and could be turned by hand this would allow you to test if the engine is binding at all.

FWIW, the larger Williams steamers state in their paperwork a "minimum" of at least 90 watts.

I just ran a semi Hudson using MTH Realtrak, plug-in lock-on, their red / black banana wire back to the dial controller (no TIU) and using a 18v 100w MTH brick. First 3 minutes loco ran well, then started slowing down... Couldn't figure out why, checked all the connections and literal got burnt when I touched the wires going into the lock-on. Mind you these are very small wires, not sure the gauge, maybe 18 ? Anyways, I opened up the lock-on to find a post was loose, tighten it  and same thing happened. Then I replaced the stock MTH wire with some heavier 16 gauge wire, the distance was about 2 feet controller to lock-on.

The result, no issues. They're power hungry locos LOL. Maybe because the Suethe smoke unit doesn't have an on-off switch, although, they should have added it.

Cheers

When I was converting my engines to BPRC, I measured the current draw of each engine.  My 14lb Williams/Samhongsa brass N&W J came in the highest at approx. 1.2A.  Most came in around .75A.

Most of my BPRC receivers are 3A, never had a problem with the J tripping the fuse.

Thanks so much for all this great info. I think between all the points made we should be able to figure this out. Much appreciated.

FWIW, I've seen more than one Williams steamer with a defective motor that drew many amps, even though they were still able to run.  I've replaced two of them when doing ERR upgrades, measuring the motor with no load would yield around 3-5 amps on the rollers at 12V DC directly measured with a bench power supply!  A clue was the motor also runs pretty hot, so that's a good test.