The reversing in the original Lionel was not done by reversing polarity; the trains ran on AC. Briefly interrupting the power reversed the train, through the E-unit. I don't have details on its operation.

 

My 6 year old grandson has inherited his other GF's Lionel set. It would only run one direction until I took it all apart and fixed it. The motor is a series wound setup with TWO field coils that are wound in opposite directions. A ratchet relay selects Coil 1, NO COIL, Coil 2, NO COIL, etc to provide the Forward/Stop with headlight on/Reverse functions. The problem I found was that the enamel insulated wire for one coil was pulled tight over the motor frame and shorting out. A little tape and pulling some slack fixed it.

 

Does your track have two or three rails?

It has three rails.

Do you have a Lionel power supply? Can you share the model number?

No, I don't have a power supply. The model number is 11540.

Photos of the set are available at http://www.collector-modeltrains.com/dash/universe/catalog_item/MT-0380895/, which also says that the train uses a 45-watt transformer.

 

There is a section of track with terminal screws. Left track is a terminal and right track is a terminal. The engine (motor) completes the circuit. You do not need the track to make a loop.

These are the era of transformers you want. 1945 to 1969.
http://www.ebay.com/bhp/lionel-transformer

I think the section of track with terminal screws is missing, but I see the exact transformer that was part of the set is available on eBay as well: http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=lionel+1025+transformer&_sop=15

So basically, if I understand all the posts correctly, I would need to get one of these transformers, since the train can't run off of a DC power supply?

 

I think the section of track with terminal screws is missing, but I see the exact transformer that was part of the set is available on eBay as well: http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=lionel+1025+transformer&_sop=15

So basically, if I understand all the posts correctly, I would need to get one of these transformers, since the train can't run off of a DC power supply?

Essentially, yes. The engine needs the voltages available from the transformer to reverse and blow whistle (if engine has that feature).

 

Essentially, yes. The engine needs the voltages available from the transformer to reverse and blow whistle (if engine has that feature).

I wonder if it's worth getting any parts for it. The transformer is missing, several pieces of track are missing, the instruction manual is missing, the smoke drops are missing...

 

I wonder if it's worth getting any parts for it. The transformer is missing, several pieces of track are missing, the instruction manual is missing, the smoke drops are missing...

I cannot get my self to be entertained by model trains. Doesn't sound like you are too interested either. Doesn't exactly fit into a college dorm either. Time for eBay?

 

I cannot get my self to be entertained by model trains. Doesn't sound like you are too interested either. Doesn't exactly fit into a college dorm either. Time for eBay?

There are people in W.PA looking for lionel on Pittsburgh.craigslist.org
http://pittsburgh.craigslist.org/wan/5106220335.html

http://pittsburgh.craigslist.org/tag/5101959385.html - this guy has track and transformer

 

I had a Marx train when I was a kid.
...
That train had three rails, like the Lionel and used AC for the tracks (center rail hot and both outer rails common).
There was some kind of alternate-action reversing relay in the motor, which would reverse direction every time you stopped the train and then restarted it.

I think the control transformer had an exposed winding with a sliding brush contact, similar to a Variac to control the voltage except it must have been a separate isolated winding). The transformer never got hot so I'm pretty sure it didn't use a rheostat.

I also had a Marx train as a child. It would change direction when the track was shorted or if the red "reversing button" (actually the circuit breaker) on the speed control was pressed. No guessing is needed to know which way I preferred to change the direction.

I agee that the speed contol was some kind of Variac although it did get hot if the track was shorted too much.