Saturday, May 05, 2007

Tender pick-up


tenderpickup
Originally uploaded by Phil_Parker.
The Armstrong locomotive is nearly finished. Painting is all done and I’ve re-assembled the various parts. With pickups fitted to the chassis the loco has been trundling up and down my short test track. I wasn’t sure it was running quite as well as I’d like though.

A model locomotive picking up power on only 4 wheels isn’t a good idea if you can avoid it. Ideally the power should come from as many places as possible. On a 4-4-0 this means the front bogie or tender needs to pressed into service.

In theory the bogie could be used but I didn’t fancy it – too fiddly. This leaves the tender.

After an abortive attempt at making a tender chassis I reverted back to the K’s original for the simple reason that it worked. Mine might have potentially looked a bit better but my usual success rate with tender chassis continued and it wouldn’t stay put on the track reliably. I’ve no idea why I have a blind spot on this but I do.

Anyway, the K’s chassis is idea for the addition of pick-ups. A simple paxolin plate on top and some phosphor bronze wire rubbing on the wheels at either end is all that is required. Careful bending ensures that they don’t act too much as brakes although this isn’t a big problem with a whitemetal body.

The only issue I had with the chassis is a problem that seems to affect all 6 wheel rail vehicles. The middle axle was a tiny bit lower than the others making the model seesaw. Some quick work with a file and drill (like yesterday’s entry but horizontal) and the axle can float up and down a bit. The other two can support the body on their own.

Result, a more surefooted model that once run in should be able to deal with track breaks and dirty rail heads. I don’t suppose anyone would notice but I do and that’s what matters.

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