Sorry, no spare, unused, rail lines around here. I live 1km from a closed one but it was converted into a rail trail. However, I did spend three years (1966 to 1969} of a 25 year railway career riding up and down a track on a three-wheel track inspection motor. It had a single cylinder 2-stroke Villiers motor, 3-speed gearbox and chain drive to the rear wheel.
The only image I can find - anywhere - of a Victorian Railways MT Track Inspection Motor. Me, at 21 years of age in 1969 at Kotta, Victoria.