steam locomotives function differently in one significant way from
their standard rod-driven brethren (the common steam locomotive), they
use a vertical or angled geared system as opposed to a standard
horizontal driven rod for propulsion. How geared steam locomotives
work, according to William E. Warden in his book West Virginia Logging Railroads, is that these cylinders drive a flexible line shaft with universal couplings and slip joints through bevel gears.
This flexibility thus allows each truck to negotiate the track
independently of the other, which keeps the locomotive on the rails and
allowing it to operate over almost any type of track (which was usually
nothing more than rails laid directly onto a hillside).
Geared steam locomotives first began to appear in the late 1870s when Ephraim Shay invented his now famous Shay locomotive. The most widely used of all geared steamers built (several thousand were constructed by the time production on the design ended) the Shay was built almost exclusively by the Lima Locomotive Works in a variation of classes (Class A, B, C, and D). However, competition with his design soon followed in the way of his two biggest rivals, the Climax and the Heisler.
Essentially using the same technology as the Shay but in a
different way these locomotives were never quite as successful as their
biggest rival. According to William E. Warden in his book West Virginia Logging Railroads, the Climax gained adhesion by employing
two cylinders, one on each side of the boiler. The cylinders were
neither vertical nor horizontal at an angle of approximately 25 degrees
and the piston rods were connected to a line shaft centered under the
boiler and mid-way between the trucks which thus powered either two or
three trucks. Charles L. Heisler developed the other notable competitor to the Shay,
the Heisler. The Heisler, while similar in appearance
to the Shay was almost identical in operation to the Climax save for
its piston rods were angled at forty-five degrees instead of the
twenty-five degrees on the Climax.
Seeing these, and other types of
geared steam locomotives in
action was a true sight to behold. Not only could they operate over
rough, uneven, and poor track conditions without a hitch, for the most
part (Shays did have an inherent flaw in that the poor track conditions
could cause drive line length change which could cause the locomotives
to run right off the rails for what appeared to be no reason at all),
but also geared steam locomotives were designed in such a way that all
wheels provided traction which afforded them tremendous levels of
adhesion (thus they could haul logs up torturous grades well over 5%!). In logging operations one could commonly see geared steamers fording
streams and creeks as logging companies would lay down track right
through these bodies of water! The reason for doing this was that
logging companies were after making money
as quickly and as cheaply as possible.
Thus, once a tract of land had
been logged, they simply picked up the rails and moved on elsewhere,
laying down a new line in the same fashion.
Today, all three of the major geared steam locomotive types not only
survive but also can still be found in operation on tourist railroads
across the nation, particularly the Shay. Perhaps the best place to
catch all three types in action is West Virginia. Not only is the world
famous Cass Scenic Railroad and its fleet of Shays and a Heisler
located in Cass, WV but also a short drive away you can catch the Durbin
& Greenbrier Valley Railroad's Climax #3 hauling the Durbin Rocket on seasonal trips.
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Geared Steam Locomotives