Two rail Shay , AC or DC?

Should be DC

The Shay you have in the photos is a Max Gray KTM Shay if it’s original motor it’s DC and the lever is a reverse lever.

Lee Gustafson

Thank you

Since it has the switch for reversing, that implies one of the old Reversing switches such as a "travis reverse switch" that guys used to reverse univeral (AC type) motors when running on DC.    We can't see the motor to see if has windings(AC) or a magnet (DC)   A DC (permanent magnet) motor would not need a reversing switch - reversing polarity to the motor reverses its direction.

So It should run on DC as mentioned above.

I did not notice outside 3rd rail pickups, so that implies 2-rail track and insulated wheels.

Check that the gears, bearings and journals are lubed.

You have a bunch of options:

First you can run it as is, manual reverse on DC.

Second,  you could replace the manual reverse with a bridge rectifier and automate the reversing function on DC with the existing motor.

Third, you could replace the motor with a similar size DC one.    I suggest similar size just to be able to use the same motor mounts etc.    There are a lot of MG and USH open frame perm-mag motors floating around.

I just thought of something about that Shay.

It is a low probability possibility that the owner was running it with an AC transformer and the motor is DC.    He may have put the travis reverse switch or something similar in there to convert and reverse the AC to DC.

If this is the case, it already has a DC motor and you can just remove the switch if  you want to run DC.  

In either case, you should be able to test it on DC.  

If you try it on AC, and it is DC motor you will get a loud hum.    Just touch the leads to the wheels so you can rmove them quickly if it hums.

Plus (and I suppose this would apply to any older model), trying DC first is probably not going to harm anything; whereas applying AC first could fry a DC motor, correct?

I mention this because I remember the first time I came into possession of an American Flyer engine (in 1973, I think). I wasn't sure what type of power it took, so just to be on the safe side, I tried DC first.

Anyway, yours is a nice looking Shay...🙂

Mark in Oregon

Thank you, all. I tried DC first, as suggested and the motor barely twitched.

So, I applied a low AC and the motor clearly turned. The switch is definitely for direction, AC motors are reversed by including a capacitor in the path. This is indeed a very handsome locomotive, I love the geared types .

You do not need a capacitor for direction.      You need to reverse the polarity on both the field windings and brushes I think.    I think that is what a Lionel E-unit does.    With a DC motor you only need to reverse polarity on the brushes.

I think a capacitor would just give you bit of momemtum, slowing down the starting and stopping.    However capacitors are also polarity sensitive and will explode if run for any time with the wrong polarity.    I have the experience with this!

Actually, you do: https://woodgears.ca/motors/reversing.html

Well I stand corrected.    My experience is primarily with model train motors, and as far as I can remember, I have not seen a capacitor used on these for directional control. 

The DCC decoders have capacitors on them, and I had one explode.    A DCC expert said it was probably assembled with the capacitor polarity reversed.     It was quite a loud pop and a large cloud of smoke out of the stack of the steamer it was in.