As my Railway runs along the bottom of a rockery then in a cutting across a lawn I decided to make a rail mounted strimmer. I did buy a couple of 80 W 12v motors but everything else was just what I had lying around. The battery was ex burglar alarm and the drive for the wheels are various parts from an old printer,
( they usually have 2 or 3 useful 12v motors.)
Nothing very sophisticated; an on/off switch for each motor, Accucraft spare wheels with the axles turned down for 32 gauge, the frame and brackets all cut out of a piece of bronze sheet I had, and the case from an old steel oil can.
But it works very well with the powerful motors removing leaves and debris from the track whilst cutting back the side growth as well. The battery was a bit limiting because it would only have enough power to cover just over one lap of the track, so when I found it had recently expired I have now fitted a 12v. 3.3 Ampere one which hopefully means I should be able to cut the edges on both sides of the cutting at one go.