where to purchase a new or used reostat foot pedal

why don't you mount a box on the side with a pot?You can get one at Radio shack for a couple bucks. Then use a momentary foot pedal.

 

I don't know **** about train sets, or sewing machines, but I would ***ume you'd have to beef up a sewing machine pedal to carry the current.

Without getting fully into variable speed drives, you can put together a simple speed control circuit pretty cheaply.
A quick google turned up this, but i'm sure there are many more out there. Should be good for roughly 1/2 hp at 110v. Never tried this one, but it seems workable. Just mount your R2 into a cheap wha pedal housing and you're good to go.




COMPONENT PARTLIST:

C1 = 2G332J or 0.0033uf Mylar
C2 = 2G563J or 0.056uf Mylar
C3 = 0.22uf K 275VAC Polyester type Caps.
R1 = 510 ohm J 1W Wire-wound Resistor
R2 = 470K Potentiometer
D1 = DB3 C312 Diac
Tr = BTA12 600B Triac

M1 = AC motor

Note: Heat Sink is needed

 

Do you have more information on the motor you are going to use? Is it a gear motor? Do you have pictures of the stuff you are trying to use?

I would find a small gear motor and get a router control at HF.
http://www.harborfreight.com/router-speed-control-43060.html

 

could be wrong but i beleive i would use a dc set up with a controller 90 volt or 180 volt it would have better controls for what your doing.in order to make a 120 volt motor that size work right you need an invertor and than at lower rpms you lose your torque.plus i beleive you need a motor that is invertor duty or it want last.i know at work all our motors that are variable speed are either dc or inverted

 

Problem is, 1/6 horsepower is about 125 watts. The only thing that will handle 10A on the pedal you pictures is the switches. The potentiometer is only good for 2 watts.
Best thing would be to buy a DC motor drive which will take a low current signal from a light duty pedal and essentially amplify it to control the motor.

KB controls are popular and lots on Ebay.

http://www.kbelectronics.com/Variable_Speed_DC_Drives.html

C