How can I make an object follow a track?


I have been trying to make an object in the game engine follow a track like a train. Although I have checked previous posts with similar questions and suggested solutions, I could not figure it out after all. Please have a look at the current blend file I am working on:
(Please do right click and save as…)
Space = Accelation
Right Shift = Brake

Thank you for your help on this matter in advance.

I think you could use an IPO and an IPO property actuator and have the arrow keys do something to the properties.

Thank you MagicMan,

I found this demo file:

That looks promising.

But I am instead looking for a method to use sensor so that the car moves as if it was a linear motor car.