Hi John
That point is too simplistic.
I operate a Gas Turbine among other prime movers, they all use
Natural Gas and I can tell you that the amount of gas required to
produce 12,000 HP or more is quite substantial. There is no way
that compressed gas could be used, the volume required even under
very high pressure would require enormous "tenders" for a normal
train let alone a VFT Freight.
The only practical way to fuel a "mobile" GT like a train, would
be with LNG (Liquefied Natural Gas) and even this method would
require the train to carry huge amounts of LNG behind it.
Gas Turbines unless the waste exhaust heat is reused (not
possible on a mobile installation) are not as fuel efficient as a
well tuned Diesel prime mover converted to gas.
(Burlington Northern pioneered natural gas on loco's BUT they
were converted Diesels not GT's.)
The cost of setting up LNG plants along the way would be very
expensive, not to mention the time lost re-fuelling.
The noise level of gas turbines is such that noise abatement
would require some pretty fancy engineering to make it mobile.
(Union Pacific Railroad knew all about that with their "Big Blow"
turbine loco's from the sixties which were banned from closely
populated centres.!)
Gas Turbines also require enormous amounts of CLEAN air, a train
running through dusty Outback conditions would soon suffer
premature turbine failure without a very large filtration system.
The machine I operate has an air filter system chamber that you
could fit a small Apartment into.
Gas Turbine technology has made big advances in recent years, but
not to the point of having them onboard to power trains as the
promoters of this high speed line would like to have people
believe.
Cheers
----Tell
Alice Springs NT