John D. et al --
Beware the Walthers transfer table.
I built an S scale transfer table -- sort of. What I did was buy two Walthers
HO transfer tables when they were liquidating their first run of these some
years ago. I spliced the bridges and the pits to make a really neat-looking S
version. I even drafted an article on how to do it. On the bridge, I simply
mounted the rails outside their location grooves and the gauge turned out just
right. I left the operator's shack off, because I knew I'd have to
scratchbuild a taller one and mount it a little farther away from the rails.
The bridge itself was motorized, and it moved by transferring motor power via a
shaft to the two cog racks in the pit. The motor got its current via brass
wipers rubbing against two of the brass rails mounted in the pit.
The thing didn't work worth a darn. The pit needs to be perfectly flat in
order for the gears beneath the bridge to remain engaged with the cog racks in
the pit. The pit molding comes pre-warped despite its molded-in stiffeners
because that's what large two-dimensional styrene moldings are -- They are
never truly flat. In order to make my transfer table work, I would have had to
replace the pit bottom with a flat metal or wooden plate, milled the cog racks
out of the Walthers pit, and bonded them to the new pit floor. I just gave up
and used a switch ladder instead of the transfer table to get locos into my
electric loco shop.
An additional Walthers design flaw: The heavy mass of a locomotive, should the
bridge accelerate or decelerate too quickly (as when the gears lose contact
with the cog racks), can cause the loco to topple sideways off the bridge.
While the considerably lighter mass and lower center of gravity of HO locos
would reduce the likelihiood of loco overturning, the pit floor distortion
would have to be eliminated entirely for the transfer table to work properly.
I hope Walthers' new release solves this...
There was an article in an ancient Model Railroader about building a homemade
transfer table. Its bridge was not self-motorized. Rather, the thing was
operated via a cable that attached to both ends of the bridge, passing over
pulleys located outside each of the four corners of the pit. The cable was
actuated either via a motor, or (preferred by the author) a hand crank. A coil
spring on a fifth pulley provided the necessary cable tension. The entire
design was simple and very stable. My regret is that I could not use it
because my transfer table would have been on a level above and behind a main
line on a lower level, so I had no room for a manual or motorized cable drive.
Dick Karnes
PS -- I never submitted the article to any publication.
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