Desire for higher power
The dawn of gas turbine locomotives
The application of gas turbines to the prime
mover of locomotive began shortly after the modern gas turbine had been
produced. Brown Boveri built the first gas turbine locomotive in 1941,
with 2000 hp electric drive. This locomotive was operated in Switzerland
and tested for the long duration.
After the WW2, many researches of gas turbine
locomotives were actively done in US and Europe. In the United States,
Union Pacific produced 4500 hp prototype turbine electric locomotive in
then 25 mass production type were produced.
At its peak
The intercontinental railroad, Union Pacific operated the high power steam locomotive nicknamed Big Boy, whose output at rim exceeded 6000 hp and weighed about 500 metric tons. In those days diesel electric locomotives could achieve only 2000 hp (1400 hp at rim) and could not replace Big Boys..
Union Pacific decided to replace Big Boys
with high power gas turbine locomotives. For this purpose, 8500 hp gas
turbine electric locomotives were produced. They were the most powerful
internal combustion locomotive build in 20th century. One locomotive consisted of
three cars, first was the motive car with the auxiliary diesel generator, second
was the motive car with the turbine generator, third was the fuel tender with
apparatus to utilize the highly viscous bunker C oil as a fuel. This 87000
liters tender compensated for the turbine's low efficiency to expand the
cruising distance. Turbines in those days consumed much fuel due to low
efficiency, roughly twice as much fuel as a diesel. To reduce the fuel consumption,
the engine was stopped while descending
a long down grade. A diesel generator was on board to maintain the
mobility when the turbine stopped, but the output was not enough to haul the
total train mass.
DB (German National Railways) used gas turbine as an auxiliary power source, because a high power non-electric locomotive was not needed. 2500 hp diesel was used as a prime mover and 1200 hp light weight gas turbine was used to boost up the total performance.
6000 hp turbine electric locomotive and direct drive locomotive were being built in Soviet Union, and China also built a turbine electric locomotive.
Counterattack of diesel
Diesel locomotives were growing more powerful
and more efficient in 70's to 80's. In the United States, single
locomotive achieved the output of 6600 hp, and 3000 hp in Europe.