What hasn’t been considered yet is that in order for the 1 for 2 unit reduction suggested by a 9000 hp. unit you would need to double the tractive effort. All current freight locomotives have ballast added so a lighter prime mover would have to be offset by adding more ballast. Current technology is already approaching the theoretical limits of metal on metal adhesion. Because of this any improvements to traction control will be subject to severe diminishing returns. The only reason to consider turbine technology is for emissions and for its ability to run on natural gas. Offsetting this will be the cost of setting up refueling stations, and the expense of fuel tenders.
The light weight of turbines would make hybrid locomotives a bit more practical, with the weight savings being used to increase battery capacity. A large battery capacity would reduce the number of starts and lengthen the time the turbine would be producing power after the start.
Thermoelectric (Seebeck effect) conversion may offer a further improvement in thermal efficiency as well as a means of cooling the exhaust. There have been some glowing reports about progress made in that field, though I haven’t seen much of that research being turned into actual products.
You’ve got a good point with respect to the price of natural gas, especially since it will probably be cheaper than oil for a long time. OTOH, natural gas is probably “easy” to convert to di-methyl ether, which makes a great fuel for diesel engines, and would likely result in much cleaner engines.
- Erik
Sawtooth500 is absolutely correct. He did not mention that at higher altitudes the temperature is much colder increasing the power output as well.
Since a turbine at idle uses about 1/3 the fuel flow of an crusing aircraft at altitude the off and on nature of Railroading would waste very much fuel. Partial power on turbines do not save much fuel over full power settings.
I would suspect a diesel loco only operates from 15 - 25% of the time at full throttle. That leads to the possible useage of natural gas powered turbines with a recuperating generator after combustion system to supply CAT. These power plants are advertised by GE as being over 50% thermal efficiency. That is much better than steam’s 5 - 10% efficiency and diesel’s what 20% ? Using these as power plants enables them to spread out the demand over either a whole RR area or onto the national power grid. + these natural gas turbines can start up on 10 minutes notice and the recuperating system at full efficiency in 1 hour.
[quote user=“blue streak 1”]
Sawtooth500:
First off, as a former airline pilot I can say that there was one inaccuracy in this thread - earlier someone said turbines become more efficient at altitude - that is incorrect. Aircraft are more efficient at high altitude because the air is thinner so there is less resistance - in actually there is also less power coming out of the turbine.
Turbines product the most power at sea level and cold temperatures. The colder the better. Really, it comes down to air density, or something called density altitude. Increase the density altitude and you will get less power out of the turbine.
Sawtooth500 is absolutely correct. He did not mention that at higher altitudes the temperature is much colder increasing the power output as well.
Since a turbine at idle uses about 1/3 the fuel flow of an crusing aircraft at altitude the off and on nature of Railroading would waste very much fuel. Partial power on turbines do not save much fuel over full power settings.
I would suspect a diesel loco only operates from 15 - 25% of the time at full throttle. That leads to the possible useage of natural gas powered turbines with a recuperating generator after combustion system to supply CAT. These power plants are advertised by GE as being over 50% thermal efficiency. That is much better than steam’s 5 - 10% efficiency and diesel’s what 20% ? Using these as power plants enables them to spread out the demand over either a whole RR area or onto the national power grid. + these natural gas turbines can start up on 10 minutes notice and the recuperating system at full efficiency in 1 hour.
Some one help us here… Didn’t UP when they were operating the big blow use a diesel to shunt around and only when they were cleared to the main would fire up and remain at full power?
Wasn’t it when the cost of bunker “C” big blow used began to approach diesel costs that UP retired the big blow? Also those “C” costs may have prematurely ended the use of UP’s oil burning steam locos?
I do think that I read somewhere that diesels were used to shunt the UP turbines around the yard. Also, it was the rising cost of bunker C that made the turbines retire. If bunker C costs as much as regular diesel, well it’s just cheaper to operate the diesels rather than the turbines.
What I’m wondering is how those turbines fared in tunnels… turbines suck an incredible amount of air. A GE-90 turbine, the kind on a B777, could suck all the air out of Madison Square Garden in 2 minutes, if you want to make a comparison.
I had thought about the GE-90 also. I do not believe a turbo-shaft version (for RRs) would fit in the present Class Is plate H clearances?. I know the fan version does not fit!
The GE-90 fan certainly wouldn’t fit (about an 11 ft diameter), but I think the core just may - not sure. You may have to get rid of the catwalks though and where would be no way to make your way through the engine. But in any case, I can pretty much guarantee you if you put a GE-90 core in a RR locomotive you would be sending so much power to the wheels that all you’d do is spin them - you’d need the locomotive plus probably 3-4 slugs to actually bring all that power to the wheels. But hey, the slugs could be fuel tenders because that GE-90 would go through so much gas you’d need tenders for it.
Another interesting note on turbines is that turbines actually produces tens of thousands of HP, and in the case of exceptionally large ones like the GE-90 they actually produce a couple hundred thousand HP - however 80-90% of that HP is actually required to spin the compressor, and only 10-20% o
U.P.'s Blows had an ancillary diesel engine for yard moves, enabling it to move under its own power with the turbine shut down. When I worked for the U.P. at Cheyenne 40 years ago, I was told of how a daydreaming hostler and inattentive ground man took a Blow into the roundhouse once under full power. It was “like World War III,” with broken glass and dead pigeons everyplace.