Reach Rod/reversing lever and Garretts

[JC Uknz 1Participant @jcuknz1]

[JC Uknz 1Participant @jcuknz1]

In considering if to build a freelance Garrett the though came to mind "How does control overcome the twisting of "Locos that bend" " ? [ David Joy's recent book }

My first thought was the bicycle brake principle of a wire inside a flexible tube which might work with a small model but I wonder how the 1:1 scale boys do it? Presumably there is not so much twist or curve of the rail with 1:1 as a garden railway with maybe 600mm radius

Edited By JC Uknz 1 on 29/11/2012 18:50:27

[Jeff DaymanParticipant @jeffdayman43397]

On very large North American Mallets the reverser was steam powered and the brakes were pneumatic, so in both cases flexible pipe joints deal with the movement of the front chassis relative to the boiler. Rear chassis on true Mallets is always on a fixed frame joined to the boiler, only the front chassis pivots. On some garden scale electric models the manufacturers have taken some artistic licence and pivoted the rear chassis also, to enable traveling on tighter radius curves, but this is not true to prototype.

Hydraulic systems could be used to do the heavier control functions, but as far as I know they were not widely used on steam locomotives (but I could be wrong on that – anyone seen them used?)

If mechanical controls are used, bellcranks with the pivot point common with the chassis pivot could be used to carry controls across the joint.

JD

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

Many of the Beyer Garrets had screw reverse with a separate screw on each sub chassis . These individual screws were linked together and into the cab reverse gear by simple telescoping shafts with articulated joints .

Very simple articulated engines had an axial pull rod with some type of pivoted joint coincident with the bogie pivots as mentioned by Jeff .

Hydraulics were almost unknown on steam locomotives though as always there were a few exceptions .

Michael Wiliams .

[JC Uknz 1Participant @jcuknz1]

Thankyou for mentioning telescoping shafts … reminded me I think I had seen them on a triple Shay in 7.25 gauge

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