Traditionally the cable would be located below the track.
http://www.cablecarmuseum.org/mechanical070714.html
You can see in this video a cable car in action. You will not see the cable, as the car grips it under ground. It is not pulled above the track and the mechanism is for the most part hidden behind the wheels.
[video=youtube_share;sZiYI8H-D9U]http://youtu.be/sZiYI8H-D9U[/video]
I am not sure what you are proposing about the engines... If each train had one engine, the train would leave backwards half of the time. If each train had 2 engines (one each in front and back), the train may appear to leave backwards every time. Aside from making the engine disappear from the back of the train and reappear at the front, what were you thinking?