Similar to a monorail, it had stabilising side rollers, invented and patented by John Barraclough Fell.
John Barraclough Fell designed and built in 1868 the original Yarlside Iron Mines tramway as a horse drawn monorail from an exchange siding at the Furness Railway to the Yarlside Iron Mines.
[1] Two years later, in 1870, John Barraclough Fell replaced it with another experimental narrow gauge railway line, dubbed the Parkhouse Tramway, named after the Parkhouse Farm west of the mines.
This had a gauge of 8 inches (200 mm) and had also a very low centre of gravity and stabilising side rollers on a central beam consisting of two trusses.
The waggons were each loaded with one ton of iron ore, and small carriages with eight passengers were run with perfect steadiness and safety at a speed of 15 to 20 miles per hour.