I extended the middle car by 4 studs to fit the PF battery box and IR receiver. The green bus from the same set donated the extra windows since I didn't have any in that color.

Just barely makes it around the curves, but has no problems with turns or switches!

First time I've used the clips on the side of the motor... I had to remove one set of wheels from the two lead cars in order to take turns smoothly.

Both the IR receiver and the battery box are offset half a stud. If only the PF wire connectors were smaller... Luckily sticking out the side of the car 1/2 stud doesn't cause any problems with the turning.

http://www.youtube.com/watch?v=fTp4a8sjOUo

So for my question, has anyone successfully added a PF polarity switch mounted on the side or bottom of one of the cars so that the tram can automatically change directions when it gets to the end of a one way rail? I'd love to be able to fit it on the middle car so I don't have wires going between, but I don't think there's any room.

Yeah, no. Not a lego switch. You might be able to fit a normal switch on the bottom from a tech store like Radio Shack or something. But that would require a lot of customizing of the PF elements.

Maybe if you can fit it in one of the other cars. Thats really the only option I see.

Edited July 2, 201311 yr by Spitfire2865

Hi there! PM sent to you.

That looks good. I just did the same to mind but slightly different. I need to take some pictures to show the difference. I also add lights to the end cars.