I'm looking for a cheap reliable motorised mechanism for moving a trolley b=
ack & forth over a 3 meter rail system. It is for use outdoors.

I'm sure something like this exists & I'd rather buy off the shelf if possi=
ble. I'd like something compact as well as I'm a little limited in terms of=
 space.

I've done some searching, but am likely using poor search terms. I thought =
to put a motor driven pulley on one side of the rails with a tensioned stee=
l cable (the small diameter kind used on boats etc. about 2-3mm diameter) l=
ooped twice around it. One end of said cable would be connected to the trol=
ley on the same side as the motor, the other would loop through a pulley to=
 the opposite end of the rails from the motor going back to the trolley. Th=
is might work, but there is potential for slippage in wet weather. There is=
 also potential for entanglement of the cable on the driven pulley.

Hope the explanation above is clear. I'll be grateful for any pointers to c=
ommercial products. Failing that any clever ideas will also be appreciated.

Thanks,

Joe
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