Desire for higher speed !
As a prime mover for locomotive, only in the U.S. gas turbines engaged in large scale commercial use, but in 60's the demand for high speed rail increased the significance of the gas turbine's high power.
Impact of Shinkansen
Success of the bullet train "Shinkansen" astonished rail industries all over the world.
In those days rail
industry was on the road of decline and extinction because people took a
long distance trip by air and short trip by car, many believed the
supremacy of automobiles and planes. Shinkansen was being build in these
Not new track
Conventional tracks in Europe and America had straight or shallowly curved track without steep slope and conventional trains had been operating at 160 km/h. So conventional lines were used for high speed operation in these countries to avoid high capital cost for the construction of new lines. A high speed non-electrified train was also expected to avoid high capital cost for electrifications.
Advancement of gas turbines
In those days the power source of airplanes are occupied by gas turbines and the turbine performance was nothing short of amazing. Many engineers were eager to apply this turbine performance to land and sea applications.
Limits of electric drive
In those days, electric motors had
comparably enough performance to achieve over 200km/h speed.
Shinkansen's maximum operating speed was 210km/h from the first
commercial operation and 256km/h at the speed trial.
the record of one time speed trial and tracks and catenaries were
severely damaged at this trial and engineers knew difficulties of
providing with electricity from an overhead wire.
Limits of diesel drive
Diesels were left behind of steams
in the performance and in 1936, German high speed DMU achieved the
record of 205km/h. 3 years after, the new record was established
This very slow improvement did not made rail engineers expect the high speed application of the diesel train and they expected the high performance of a gas turbine to build non-electric high speed lines.