Return of the Turbines?

[jeffshultz]

When I was wandering around Railpower, Inc's website looking at photos of the Green Goat for the Tower 55 Poll thread, I found this:

http://www.railpower.com/products_td.html#cingl

"RailPower has patented a design for a compressed integrated natural gas locomotive (the "CINGL"). The CINGLTM is a patented gas turbine locomotive fueled by compressed natural gas. This technology has the potential to revolutionize the mainline freight locomotive industry in North America."

"The design, featured above, has a 5,500 h.p. recuperated industrial turbine made by Solar Turbine, a subsidiary of Caterpillar, with a thermal efficiency of about 40%. Turbines have made great efficiency improvements over time relative to a slower improvement in the efficiencies of the diesel engine."

"Locomotive: The resulting locomotive is an operator's dream. While eliminating over 99% of the harmful NOx Emissions and diesel particulate the CINGLTM achieves the current industry goal of high horsepower locomotive units. The customer can request the CINGLTM in versions of up to 10,000 h.p. (+7MW), a power level used in electric locomotives in Europe where the physical constraint of diesel technology is not a problem."

Calling UP, calling UP!

[Anonymous]

I would believe this is possble now, since extreme high horsepower like 6000 HP has proven to be a problem in one CC unit. All of the Union Pacific 7500 class have been de-rated back to 4400, if I can believe an article recently.

Most of the 6000 HP GM units are sidelined and are being returned for credit or something since they failed early and often. However, they should hurry since GM sold the EMD division and is also going broke at this moment. If you can derate the Turbine to 4500 like the first UP turbines, this might be a solution for the railroads.

Just some thoughts.

[jrbernier]

I have read the articles, and what I suspect is that these turbines are very good for constant speed applications where they are bolted down to a firm base(like a small powerplant/peaking operation). Underway vibration in a hostile rail enviroment has killed several turbine projects. The UP turbines were quite sucessful using cheap at the time Bunker C, but they lost favor due to higher fuel consumption/maintenance and improvements in diesel electrics.
6000 hp engines are still a goal that most North American railroads would like. The present attempts by the 'Big 2' and CAT have resulted in prime movers that have far more vibration that the 710 and FDL power plants in the curent locomotives. Remember, in the late 60's hp got up to 3600 hp, then dropped to 3000 hp by 1972, and in the early 80's 4000 hp locomotives became the norm. Give the builders time, and they will improve the technology....

Jim

[Leon Silverman]

I would not be so fast to think a modern Gas turbine would necesssarily not be able to withstand the heavy vibration of locomotive use. Gas turbines in Destroyers have to operate in typhoons and are shock tested to remain operational after an explosion unless the turbine is destroyed directly by the blast. Airplane jet engines have to survive the "chicken" test where dead birds are shot directly at the blades. The result has to be chicken salad without any turbine blades mixed in.
A little historical perspective might be appropriate here. Diesel engines displaced steam engines which had been around roughly twice or more as long as diesels. Relatively primitive diesels were able to eliminate steam engines at nearly the hieght of there development. The unsuccessful turbines of the 40's and fifties utilized infant turbine technology. The brand new Airbus 380 could not possibly fly with those engines. If you think a turbine can't stand vibration, look at the power plant of an M1 Abrams tank. The gun is stabilized. The chasis that the turbine engine is mounted on bounces very nicely, thank you.

[tatans]

Sooner than you think the next generation of locomotives will be turbine powered, with the new technology in place look how small turbines have become on aircraft and what h.p. they generate, In the very new future you will wish we would have save a few old diesel powered antiques.

[Anonymous]

One minus point for gas turbines - gas as in principle of operation, not fuel used - is that the critters do not idle too economically. Their idle fuel consumption necessarily is higher then that of diesels.

Also, controlling a GT is like riding a bucking bronco. This is due to the fact that basically, all a GT consists of is a rotating shaft which due to its low mass can change its RPM very very quickly. This necessitates extremely tight fuel-flow control unless you want the GT to hunt all over the place in response to varying loads, which could lead to potentially dangerous overspeed scenarios.

On the other hand, take the GT to too low a speed, and instead of stalling and stopping like any self-respecting engine, it will insist on hanging on and trying to accelerate without success and melt itself in the process.

Since GT components have very low mass, temperature fluctuations within the components themselves, brought about by varying loads, can thermally stress them out to the point of early failure. The first practical GT's typically had a service life of less then 50 hours. Nowadays, aviation engine components are normally lifed by the number of start-takeoff-land cycles due to thermal fluctuations brought about mostly at start-up and takeoff power phases.

The above make the GT most suitable as a constant high load prime mover. This holds true for aviation, nautical and grid power generation. The Abhrams tank is a miltary application, so normal economical constraints usually do not apply.

I am no expert in train operation, but the only place where a GT powered locomotive can even begin to earn its keep is in a long haul, as-few-as-possible-stops operation, dunno, how about cross-desert? Or possibly a trans-continental express?

One solution for minimising thermal stress - read maintenance - is that once started, the GT is maintained at high idle, or loading the alternator artifically - kinda like a ?dynamic brake? - during low- or no- load phases like station stops or coasting, but the fuel would still be flowing, thus contributing to running costs.

And for finals....Starting is a very stressful time for a GT - the thermal stress bug-bear again - so if a GT has to be shut down for any reason, it must first be allowed to cool down sufficiently before another start is attempted. A typical restart delay on an aircraft engine is 10 minutes.

So the question I pose for those who are still with me [zzz] is this.... Is a gas turbine really suited for railway use? [soapbox]