Gas-powered locos

[NW Mailing List]

Dominic:
 
I promise I'm not picking a fight, but you lifted portions of the Wikipedia 
 UP citation, but not the portions that describe how the engineering 
problems  were mitigated.
 
In the end, rising cost of fuel and ever-improving diesel-electric  
technology, added to the age of the GTEL units, meant their time was over.   And, 
as you imply, operating conditions on BR were certainly far from optimum  for 
GT applications, whereas UP came a lot closer.  As an example, to get  
around the high specific fuel consumption at idle, the later GTELs on UP would  
shut down the turbine on the long downgrades, and use the six-cylinder 
Cooper  Bessemer auxiliary diesel with its accompanying generator to provide 
excitation  to the traction motors, running as generators for dynamic  braking.  
 
In any case, you're right, LNG/CNG is a better fuel, so the Russian  
experiments might not have those issues.  The economics of the fuel will be  
different in different places; in North America, we're about to the point that  
natural gas (in whatever form) is cheaper than other fuels.  
 
Good dialog.  Thanks for pointing out these considerations.
 
Dave Phelps
 
 
In a message dated 12/21/2013 6:48:49 P.M. Eastern Standard Time,  
nw-mailing-list at nwhs.org writes:

 
Thanks Dave


I  implied oil burning (of the earlier experiments/experiences) but perhaps 
that  should have been more explicit.


Problems  with fuels were encountered in the UK e.g.


Ash  from the heavy fuel oil damaged the turbine blades, and the combustion 
chamber  liner required frequent replacement due to damage. 



And  efficiency was a problem.


When  reliable operation could be achieved, it did show itself capable of 
meeting  expectations. Unfortunately, however, it was neither possible to 
achieve an  acceptable level of reliability nor to operate it under conditions 
which would  allow reasonable fuel economy.


http://en.wikipedia.org/wiki/British_Rail_18000


UP  encountered similar problems:


Fuel  economy was poor, the turbine consumed roughly twice as much fuel as 
an  equally powerful diesel engine.


Soot  buildup and blade erosion caused by corrosive ash plagued all of the  
turbines.


 (http://en.wikipedia.org/wiki/Union_Pacific_GTELs) 
http://en.wikipedia.org/wiki/Union_Pacific_GTELs



I  suspect that it was therefore the more unforgiving nature of gas 
turbines  as to fuel that was the  problem as well as the other problems 
encountered e.g. with control equipment  etc.


LNG/CNG  are a much purer form of fuel ....... and would appear to be in 
plentiful  supply (tho' perhaps more because of fracking - something of a 
political  problem in the UK).



Dominic
London


I walked 12 miles for the Pirate Castle for the 4th time on June 22nd -  
please help by_  sponsoring me_ (https://mydonate.bt.com/fundraisers/pirate1) 


 
  
____________________________________
 From:  NW Mailing List <nw-mailing-list at nwhs.org>
To: nw-mailing-list at nwhs.org  
Sent: Saturday, 21  December 2013, 2:24
Subject: Re: Gas-powered  locos



 
Dominic:
 
The gas-turbine locomotives you mention in passing did not burn LNG or  
CNG; "gas-turbine" referred to the prime mover.  The  Russian  experiment would 
appear to be the same kind of prime mover, but burning  LNG/CNG.  The 
American gas-turbine locomotives, all of which ran on the  Union Pacific 
Railroad, burned heavy oil.  They were technically  successful, and until the price 
of the residual crude oil they burned began  to rise to approach the cost of 
diesel oil, they were economic successes as  well.  Because UP operations 
required long periods of full-throttle  operation, they did not fall prey to 
the typical shortcoming of a gas  turbine, high specific fuel consumption at 
low throttle settings.
 
I'm not a mechanical engineer and won't pretend to be an expert on the  
subject, but I've always understood that a gas-turbine was much more  forgiving 
on what kind of fuel it was fed (injector nozzles obviously  optimized for 
the fuel) than a diesel, which is why we haven't seen many  successful 
LNG/CNG locos so far.
 
<snip>










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