Geared steam locomotives were mainly used in the logging and mining
industries. In the 1880s they replaced mules and oxen as the primary source
of motive power between the source of the lumber or minerals and the mills.
The railroads at these locations often used rough, lightweight, temporary
tracks that followed the contours of the land. As a result they were not
suitable for a typical side-rod steam locomotive. In the 1870s, Ephraim
Shay began working with the Lima Machine Works to design a locomotive that
would be suitable for this type of track while being cheaper to operate
than a team of mules or oxen. The Shay steam locomotive went on to become
the most popular of several types of geared steam locomotives.
There were several types of geared steam locomotives in North America -- the
Shay, the Climax, the Heisler, and the Willamette. Lima built around 2,770
Shays between 1880 and 1944. The Climax Manufacturing Company built around
1,100 geared locomotives between 1888 and 1928. Heisler Locomotives Works
built more than 600 geared locomotives between 1891 and 1941. The Willamette
Iron and Steel Works built 33 geared locomotives between 1922 and 1929.
The Shay (or sidewinder as it was sometimes called) was the most widely used
of the four major types of geared steam locomotive found in North America.
The Shay design was patented by Ephraim Shay. Although a number of changes
were made to the original design, the characteristics of Shay locomotives
are easily recognizable. They were built by the Lima Locomotive Works or
Lima, OH. They had three vertical cylinders (very early models had two)
on the right side of the boiler. The boiler was offset to the left to
offset the weight of the cylinders. The drive shaft ran from the front
of the locomotive to the rear connecting the crank shaft of the motor to
gears on the outside of the wheels. Of the 2,770 built in the USA only
117 survive today.
Heisler geared steam locomotives had a V-2 cylinder configuration with the
crank shaft centrally located underneath the boiler. The two cylinders were
oriented at a 45 degree angle, one on each side of the boiler. The drive
shaft was connected to the outboard axles on the front and rear trucks
through a gearbox. Side rods were used to transmit power to the inboard
axles on these trucks. Apparently, the Heisler was the fastest of the
geared steam locomotive designs. A few builders produced locomotives of
the Heisler design. Early models were built by the Dunkirk Engineering
Company of Dunkirk, NY. Stearns Manufacturing Company of Erie, PA which
later became the Heisler Locomotive Works produced most of the 600 Heisler
locomotives that once existed. Only 20 Heislers survive today in North
America but a few are operational.
Climax locomotives had two cylinders that were located somewhat more
conventionally (than the cylinders on other geared steam locomotives) in
front on either side of the boiler although angled upward. The piston rods
attached to a horizontal crank shaft located under the center of the boiler.
At the center of the crank shaft was a transmission. The transmission had
two drive shafts: one coming out the front and one coming out the rear.
The two drive shafts were connected to gear boxes in the front and
rear trucks. The gear boxes in each truck was connected to both axles,
providing power to all wheels. All Climax steam locomotives were built
by the Climax Locomotive Works (formerly Climax Manufacturing Company)
of Corry, PA. Of the 1,100 Climax locomotives built only 13 survive today
but several of them are operational.
Willamette locomotives were essentially the same as Shay locomotives
with a number of improvements. They were built by the Willamette Iron
and Steel Works of Portland, OR after the original Shay patent expired.
The improvements that the Willamettes had included:
- Superheaters (Shays usually did not have superheaters)
- Welded boilers (Shays used bolts)
- Walschaerts valve gear (Shays normally used Stephenson valve gear)
- Cylinders all facing the same direction (rear cylinders on Shays faced the rear) Compare: Willamette Willamette Shay
- All cylinders were positioned forward of the cab (the last cylinder on Shays protruded into the cab) Compare: Willamette Willamette Shay
- Valve chests turned outward
- Truck springs inclined toward the bolster
- Improved efficiency
Some of the later Shays included some of these improvements. Only 33
Willamettes were built. Of those 33, 6 still survive today.