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a lot of work into the unit; it even has ball bearings for the<br />
drive shafts. But why it easily released in one direction and<br />
not the other needs some more experimenting.<br />
There had to be a better way. One that will work properly<br />
each and every time without fail, and be sturdy enough for<br />
years of service. I had a Grandt C-16/Shay gear drive unit<br />
that I bought while building in On3, but never used. It has a<br />
tiny precision motor, gear reduction, and is finely made. As<br />
shown in Photo 2 (valve gear in forward position) and Photo<br />
3 (in reverse), I made a lever to attach to what was normally<br />
the geared drive axle and this lever moved the attached<br />
time. I have gone over to DCC control and this will work as<br />
each motor has its own decoder. When programmed the<br />
Grandt gear unit moves the valve gear and power reverse<br />
slowly into position that looks almost prototype. Switch to<br />
the main motor decoder and the loco ponderously begins to<br />
move. That 2-10-4 is not finished yet but the valve gear will<br />
shift quite nicely without fail!<br />
I always have several projects going at the same time,<br />
so another loco under construction is a Burlington class B1<br />
4-8-2 and another shifter was required. I did more experimenting<br />
with small Sagami motors, flywheels, and different<br />
gearboxes, all trying to fit into available space. Nothing<br />
worked as the power required to move the gears made the<br />
shift too rapid, sort of slam-bang! I have purchased a couple<br />
of precision motors from “Motorman” and like them very<br />
much. He carries many sizes and an e-mail request brought<br />
a very small (read tiny) motor with a gear head for reduction<br />
(Photo 5). To reduce the movement speed even further,<br />
I used a worm gear drive from the parts box. This also has<br />
the benefit of locking the reverse shaft when in position as<br />
rod forward to the reverse shaft. This motor will stall when<br />
reaching full travel in either direction. In Photo 4 you can<br />
see that the scratchbuilt Barco power reverse also moves<br />
with the reverse shaft. Also note that the connecting pin is<br />
not in place. This setup works great and without fail. But you<br />
can see the problem with this unit; you can’t use it with traditional<br />
DC control as both motors will operate at the same<br />
18 • O <strong>Scale</strong> <strong>Trains</strong> - Jul;y/Aug ’08<br />
the Walschaert reverse link movement back and forth transfers<br />
that wiggle movement up into the reverse shaft by the<br />
linkage. This doesn’t look prototypical at all, so the locked<br />
worm gear prevents that wiggle.<br />
Photo 6 shows the radius rod (the long horizontal one) in<br />
the top of the reverse link which is in engine reverse position.<br />
Photo 7 shows the radius rod in the bottom position<br />
which is forward. Sort of like low gear in an auto. Between<br />
the bottom and up travel to the center of the reverse link<br />
(neutral) are different settings used by prototype steamers for<br />
power and the economical use of steam. We do the same<br />
when shifting the transmission in our cars.<br />
This setup is still being worked on, but so far it works just<br />
fine. Note that in the mounting for the shifter motor, I have<br />
made provision to install its decoder underneath the motor.<br />
Also, that mounting frame looks a little wimpy; so I will<br />
solder some side bracing to stiffen everything for gear movement.<br />
The mounting block for the round gear will have pin<br />
stops for the fore and aft swing of the lever. These will also<br />
be the stall points for the gear motor.<br />
With a decoder powered shifter, it is even possible to set<br />
the valve gear to neutral when the engine is stopped. How’s
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