This was just a generic example. Something like this maybe:
I’m assuming you have a particular reason to use a Timeline for that sort of thing. Moving something with a slider can be achieved with something less complicated if no timeline is involved, of course. I can imagine this being quite handy if you’re driving an object along a spline, for example, and want to manually slide it along the path back and forth.
Hope this helps but do tell if you’re having problems achieving the precise effect you’re after.