Power to track, insufficient to run train

Just because the transformer is “humming” is no guarantee it is putting out power.

Possible short circuit/poor electrical connection? Or maybe something got lodged in the gears of the locomotive? Just a few guesses.

Do the drivers turn freely by hand?  Dried grease or a bent rod could prevent them from turning.

How many volts is the transformer putting out?  Does the engine's headlight come on?  Does the engine get warm or sound like it's trying to run?  No to either of those would mean no power getting to the engine.

http://www.thortrains.us/manual1.html

The most likely thing that happens is that there is a derailment causing a short and the transformer circuit breaker is thrown. Another common thing is the e-unit lever gets bumped into the wrong position. Do you get an idea of how difficult it is for us to guess what the problem is? We don't know the engine number or the transformer model or whether or not you checked the e-unit lever. You need to give us more data, you need to do more tests, and you need to show us pictures or videos.

A simple "maybe" is that the lock-out lever (located UNDER the shell, just ahead of the cab) is set to a neutral or non operating place.  I could see where someone picking the engine up could inadvertantly move the lever.

This feature allows you to lock out the E-unit, (reverse unit) keeping it in neutral, forward or reverse, wherever it is set.  This is so in a power inturruption,  the loco will not shift to neutral or back up.  IF it IS in neutral, the buzzing would be pretty loud, though.

Try switching it one way then the other, and see if that returns normal running.

And you should buy and always have, a basic multi-meter (can be bought for $5- 10, at a yard or garage sale).  This allows you to check for power output from the transformer rather than guessing.  It should be putting out 16-18 volts (AC!)

@ADCX Rob posted:

http://www.thortrains.us/manual1.html

Thanx, this enabled me to realize I didn't place the lockon correctly.

Alas, before I could try it, my crazy calico cat knocked the engine to the tiled flooring.

The rail on the right now allows the cross head r.n. to pop out, so the gears and wheels no longer turn fully.

I'm going to take her to a shop here in New Orleans (Kenner) tomorrow.

Thanx for all the responses, this old gal learns something each time she reaches out.

I got her chugging along again! Rob's diagram was the key to power. I then hauled out some of my jeweler's tools, and with a dental pick, and crimp pliers, got the rail and cross head perfectly aligned!

I think I need to clean the tracks, they sound gritty? What, if anything,  should I use?

Again, thanx so much! Y'all are a cool bunch.

Track cleaning is a hot topic here, but most of us use alcohol (plain, no scent or color) on a paper shop towel or thin sponge. Small don’t: hand sanitizer has aloe or other gelling agents and can leave a film on the rail, which you don’t want. The big don’t is steel wool (too hard to pick up tiny bits, even with a good magnet) and the second big don’t is anything really gritty that doesn’t clean off easily.

Eventually you might want to invest in a track cleaning car that drags a weighted pad around, with or without alcohol. Remember to check locomotive wheels, too. They crud up fast even in storage.

You’re absolutely right that jewelers’ tools are really, really handy. Fine solder, tiny soldering irons and especially needle nose pliers can be worth their weight in gold even in O gauge, never mind the smaller stuff. Those little glasses repair kit screwdrivers are another good find.