I have no particular interest in model railway layouts, but curiosity got the better of me, and I bought this decrepit-looking controller from the Animal Rescue charity shop. [no mains plug, no PAT sticker]

Hammant & Morgan were renowned for the build-quality of their controllers, so I thought it might be worth a look.

Aside from the obvious signs of age, the worrying thing is the “handling” damage around the Resistance Selector. … [!]

Having attached a Mains Plug, I was a little surprised to see a ‘No Load’ output of 32v on the terminals, but the reversing arrangement works fine.

Having removed the control-knob, and drilled-out four small pop-rivets; I removed the top, and yes, the majority of the thing is nicely built … the exception being that Resistance Selector, which appears to be some sort of ‘lashed-up’ rotary switch with a flexible wire attached. … Why? one might ask!

The order of assembly means that the details of its construction are not visible at the moment, but I intend to tear-down the whole unit … so they will be revealed in due course.

Before I do, however … I would be grateful if someone ‘versed in the Art’ could explain the purpose, and modus operandi of this Resistance Selector

… I presume it has something to do with the length/complexity of the track, but I have never seen it explained.

MichaelG.

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Ref. https://www.binnsroad.co.uk/railways/handm/