If you want to post an image, right
click on the pic you want to post, select Properties
, and copy
Then paste the address into the text of your post, then put
on the back... and badda-bing badda-boom it shows up.
(My Mantua has just one traction tire too...
The key to your situation is a proper diagnosis. It's either electrical, or mechanical. Either poor or intermittent electrical contact... or binding gears. This needs to be determined before the right fix can be implemented. I don't believe that you have a serious problem with your engine, so hang in there and we'll explore the possibilities.
If it's gears... when the motor spins in one direction, the worm gear on the output shaft pushes in one direction along its axis of rotation, and when spinning in the other direction, it pushes the other direction. perhaps it's binding against one end. You'll probably want to take the top of the engine off to expose the motor, this can help you a lot in determining what's going on. First things to check is if the bronze output shaft sleeves of the motor have a little oil on them and turn freely, and then if the drive gears have a little grease on them and move freely. If it's gears, when you rotate the armature of the motor with your finger it will turn more freely in one direction than the other.
(edit: oops... sorry, you had already posted while I was doing this one.