Guys i want you to look at this, locomotive:

http://www.youtube.com/watch?v=Ij5bC2KzMeM

Look at the wheels of that, locomotive...

Do you see the metal bar that zigzags going left and right and semi up and semi down...Well look at a bycicle...you see the: pedal and crankarm of a bycicle...Well what if you had some kind of motor aparatus with the locomotive wheels bar in the bicycle connected to the pedal and crankarm of the bicycle and you had it in the front wheel so that the front wheel will crank/pedal/row the rear wheel and the rear wheel in turn PUSH the front wheel....All you needs is a motor with some kind of fuel with the locomotive bars zigzaging back and fort, left to right...Finding a motor like that is easy and and it should pedal the bicycle for like: 3,000 before refueling...Just hope the fuel is not gasoline but something else....And you have something like an: Electric Bicycle....

In fact the locomotive metal that zigzags could pedal/crank the rear crankset and pedal/crank the rear wheel...