(updated January 12,
following links are to patents on the Google patent site. Most
are for interesting components or concepts patented in the latter days
of mainline steam in the United States (~1945-1955).
3000 Patent- The patent for the modern steam locomotive devised in
the early 1980's by American Coal Enterprises, the locomotive which
first inspired these web pages.
Franklin "Long Compression" Poppet Valves- A development of the Type B
rotary cam poppets, the camshaft profiles were designed to improve the starting
and low-speed traction of steam locomotives, one of their weak points compared
air preheaters- Combustion air preheating is common on
power plants but almost unknown on steam locomotives. Preheating
improves combustion efficiency, and in the case of this patent, was
claimed to reduce boiler maintenance by reducing stresses caused by
incoming cold air. These particular preheaters are mentioned in
Eric Hirsimaki's book on Lima as having been applied to a C&O
2-10-4 in the 1930's. However, the man in charge of their testing
said they so dramatically reduced boiler maintenance most of the
railway's boilermakers could be laid-off and he recommended against
Balancing Shafts - Balancing shafts, geared to the
crankshaft, have been used in certain internal combustion engines for
many years to reduce vibration. This patent shows a design for
applying this concept to 2-cylinder steam locomotives, which were
impossible to balance completely with the normally used method of
adding weights to the driving wheels.
boiler patent #1- Will Woodard, famed chief engineer of the
Lima Locomotive Works, was convinced that water tube boilers held
promise for steam locomotive applications. He wasw particularly
interested in the adaptation of the LaMont marine-type forced
circulation water tube boiler to steam locomotives, and this patent and
the two below cover this concept.
expander driven steam locomotive- Many attempts were made to devise
alternative driving arrangements for steam locomotives other than the
traditional reciprocating pistons and rods. This patent shows a
design using twin-lobed rotary expanders, like the Roots blowers used
as superchargers on GM 2-stroke diesel engines, to turn the drivers.
steam over-fire jets- Over-fire jets were applied to steam
locomotives to introduce "secondary" combustion air to the firebox to
improve combustion. The extra air was admitted above the fire to
aid in the combustion of gases released by incomplete combustion of
coal. Most designs used live steam jets blowing through openings
in the sides of the firebox to induce air to flow into the
firebox. This patent covers over-fire jets which would have used
exhaust steam to induce the secondary airflow. This would have had the
advantage of being largely self-regulating, as the harder the engine
was worked the more secondary air would be admitted.
Brakes- Conventional train braking systems
relied on brake shoes pressed against the wheels of the cars and
locomotive to retard the train. The brakes were actuated by
vacuum or compressed air and worked well in most instances.
However, in mountainous areas which required extended brake
applications, overheating of the train's wheels could result and brake
shoe wear was rapid. "Dynamic" brakes were made popular shortly after
the introduction of diesel-electric locomotives. This form of
braking turned the diesel locomotives drive motors into generators
which fed their current to electrical resistance grids on the top of
the locomotive. This could be used to help slow trains on long
down grades without the use of conventional brakes. The ability
to use dynamic braking was considered to be a significant advantage of
diesel locomotives over steam. However, a form of "dynamic"
braking was possible with steam: the counter-pressure brake. This
basically converted the locomotive's cylinders into a compressor, which
retarded the train. This form of braking was employed on several
mountain railways in Europe but seems to have been almost unknown in
the U.S. This patent covers details for an improved form of
counter-pressure braking for steam locomotives.
reactor design for locomotive - In the 1950's, nuclear energy was
thought to be the power of the future, and designs were prepared for
everything from nuclear powered aircraft to nuclear powered railroad
locomotives. This patent covers the design for a nuclear reactor for a
locomotive, which would have course been steam powered.
Fortunately, it wasn't long before designers realized that the
potential drawbacks to nuclear power in these applications (imagine a
train wreck with a nuclear locomotive) outweighed their potential
benefit. Nuclear power is used to power trains, but via
generating electrical power at large stationary plants which powers