The Shay locomotive was designed to be used in a resource setting. Resource
railways are one type of industrial line constructed to permit the removal of natural
resources from remote areas to either processing centres or more centralized
transfer points. The mining and forestry industries are two fields best known for
their early reliance on railways to transport raw natural resources from remote
areas. In the British Columbia forestry industry, railways were used to transport
timber up until the 1950s, when they were replaced by logging roads and trucks.
Forestry railways were comparatively short-lived lines that were built cheaply and
frequently below the standards of mainline railways. The tracks were characterized
by sharp curves and steep grades that matched local terrain and the logging
company's limited budget rather than rigid railway standards. These lines
served as feeders to more central loading areas where the rough logs that had been
transported on simple log cars were loaded onto more substantial flat cars pulled
by conventional locomotives or moved by water to mills for processing.
Merrill & Ring Shay locomotive No. 4
at Theodosia Arm, B.C., ca 1926.
(Courtesy B.C. Provincial Archives)
In British Columbia's forest
industry, the Shay locomotive was the
most popular type of geared steam
locomotive available. Its distinctive
design featured vertical pistons located
to the side of the boiler. The pistons
turned a crank shaft that was connected
on either end by universal and slip joints to a drive shaft, which was connected to
bevel gears on the shaft and wheels. The gears transmitted the pistons'
power to the wheels of the trucks. The Museum's Shay has two four-wheel
trucks. The wheelbase of these powered trucks is only 4 feet4 inches
(132 centimetres), approximately half that of conventional engines with similar
tractive force and weight. These powered flexible trucks allow the Shay to operate
on curves more than three times sharper than conventional steam locomotives. The
gearing, while limiting speed, allowed the locomotive to haul considerable loads up
and down steep inclines.
A Lima Locomotive Works photograph of the brand new Merrill & Ring
No. 4 engine showing the pistons mounted on the side of the Shay and its
distinctive transmission system to each of the two trucks. (Courtesy Lima
Locomotive Works, 1925)
The Shay's boiler is offset left and the vertical three-cylinder engine is
located on its right side. The locomotive was also equipped with a steam
siphon so that the tender tank could be refilled with water from fresh-water
streams or ponds along the line. The fact that the majority of moving parts are
visible and easily accessible made the locomotive somewhat easier to repair
and well suited to the rough conditions encountered in many logging
operations. The locomotives were often wood fired, a logical choice in a
logging operation. However, by 1926, the Museum's locomotive had
already been converted to burn oil.
Merrill & Ring locomotive No.
3, ca 1926. The large balloon
smoke stack was used when
the locomotive was fuelled by
wood. (Courtesy Prince Rupert
Historical Museum, Prince
* The numbers in brackets are
the accession numbers of
artifacts held by the Museum.