Topic: TEI #010 - Solved. The Pedrail Wheel, invented by B.J. Diplock

[Tom_I]

The traction system used on this vehicle has a specific name.

For a point, can you tell us what it is called, who invented it, and when?

[Tom_I]

Any traction engineering experts out there?

[Tom_I]

Open to all.

[pnegyesi]

Pedrail

[Tom_I]

That's the one!

Can you fill in the requested details? I'll lock it until your next reply.

[pnegyesi]

From a forum: here is Mr Bramah Diplock's design patented in 1893 (No. 19682), and built as a steam-driven four-wheel-drive, four wheel steer machine in 1898 by Taskers, then re-designed and re-patented (Patent 14710 of 1899) with the "Pedrail" wheels. This is the second machine built, once again four wheel drive, a compound under type engine of 108 ihp and built by Kerr, Stuart, I don't know the date but presumably around 1900. Diplock found that having a differential on each axle was not enough, so added a third diff.

[Tom_I]

Well done, that gets you the point, though that forum article confuses things slightly. The 1893 patent is only for the four-wheel-drive system for a traction engine, while the later one is just for the Pedrail Wheel.

Yes, it's the Pedrail Wheel, invented by British engineer Bramah Joseph Diplock - he's the man in the bowler hat standing next to the wheel in the puzzle photo. It's difficult to date it precisely, as it presumably took some time to develop, but as noted above Diplock filed a patent application for it in July 1899.

Contemporary reports tell of its remarkable traction over soft ground, and ability to negotiate rocks and other solid obstacles on hard ground. It was considered by the British War Department for use in tanks in WW1, but was rejected in favour of the continuous track-laying system, which is technically much simpler, and which has certainly stood the test of time.