Driving a tricycle

[Mayhem]

Looking for ideas on how to drive an un-manned tricycle back and forth down a hallway.
The floor is sloped and built up on 2x6 framing.
Suggestions?

Thanks!

[RJ Productions]

Depending on the weight, how about a geared motor? Change the size of the disk attached to the shaft of the motor to change the distance it travels

trike.jpg

[monsterwax]

The trick is to actually have someone riding the bike, but have them invisible so it looks like it's empty. It fools them every time!