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Gas-powered trains

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Gas-powered trains

  • Houston Chronicle staff writer Zain Shauk recently wrote an article about the railroad industry’s growing interest in the low cost of natural gas and its potential development as a power source for locomotives. The article got me thinking: Will gas-powered trains ever become a reality in a big way? How long will it take for the technology to be successfully developed and tested? The article also prompted the subject of this week’s poll question: Do you foresee a day in the not-too-distant future when railroads will run trains on natural gas? I’m interested in knowing what Progressive Railroading readers think about the idea. Consider sharing your perspective by making a comment on myProgressiveRailroading.com and/or by answering the poll question at Progressiverailroading.com.

  • I responded to the poll on Progressive Railroading by answering "yes" to the question, "Do you foresee a day in the not-too-distant future when railroads will run trains on natural gas?"  This is an interesting topic with a wide band of issues.  

    The poll question is written with choice of a "black" or "white" answer where in reality it is a "shade of gray".  For example, define "not-too-distant" future . . . For me, this would usually be a period of six to 12 months.  However, for this issue with the tech issues of developing gas powered locomotives, I took "not-to-distant" future to be in the next two / three to five years.  

    Another point to define would be the the operational area; line haul or yard / switching.  Each has different locomotive requirements and demands.  I am not an engineer but as a laymen, but my expectations are that the requirements / demands of line haul operations would present the greater challenge to developing a natural gas powered locomotive versus one for yard / switching thus a longer development cycle.  

    Regarding the the economic benefits, and again from a laymen's perspective, line haul locomotives are more fuel efficiency than those in yard / switching service and thus would provide the greater benefit to the railroad in switching to natural gas.  The other potential benefit would be reducing the locomotives carbon footprint as natural gas is cleaner than diesel.  Again, the initial benefit is greater in the yard / switching arena where the activity is confined to a small geographic area as compared to line haul operations.

    Therefore, as my conclusion, I would expect railroads to switch to natural gas sooner for yard / switching operations with line haul following a few years thereafter.  Of course, this is all based on the technology being in place which allows for the economic and environmental benefits of natural gas being realized while not; decrease operational performance, increasing overall operating and M&R costs, etc. The other critical factor would be the initial investment costs.

  • Julie,

    You may want to contact Micheal Iden at the Union Pacific Railroad on this topic.  He gave an excellent presentation entitled "Liquefied Natural Gas (LNG) as a Freight Railroad Fuel: Perspective From a Western U.S. Railroad".  His presentation outlined some of the challenges and opportunities for implementing LNG locomotives.

  • I'm a reader; but internal combustion engineering is way over my head.  For one, I would be interested to know how natural gas compares to diesel in power output in a reciprocating engine that might be converted from diesel fuel?  Would a gas turbine be more practical?  

  • Thanks for the tip! I'll check it out.

  • Turbines tend to be more efficient than piston-driven engines at their optimal operating point (usually close to the maximum output).  The challenge comes under partial loading, when a machine is putting out a fraction of its power, away from that optimal operating point.  Turbines drastically underperform piston engines there.  That is why turbines are rare in locomotives but common on the power grid.  The interconnected nature of the power grid allows for turbines (and other sources) to complement each other, and thus operate closer to their point of optimal efficiency.

  • I read in another forum that recuperating, exhaust-heated intake air, gas-turbines were quite competitive with diesel.  As with the genset concept, multiple gas turbines were tried for the United Aircraft Turbo Train where full power wasn't needed after attaining track speed or during braking and idling.  

    Sadly, there was little opportunity on or outside the NEC for a 171 mph train around 1967; but that's off-topic.

  • Another point: light turbines are very, very sensitive to air feed compared to your average diesel.  Stationary plants can handle this well, as can aircraft, since most of the time they are drawing very clean air, give or take the occasional hapless bird.  For a ground vehicle operating in gritty environments, it can be a very different thing.   (the big units looked at for coal gasification, of course, were another story.)

  • This discussion is interesting and important.  Far more efficient for railroad use of natural gas would be to generate electricity with the gas and run the trains on electricity.  There's far less reinventing stuff that way, plus natural gas has a lot less Btus than diesel fuel, so essentially the locomotives would all be "derated" to a degree using the gas for direct combustion.  Alan Drake has published extensively on this point.

  • Excellent point, David Foster.  An additional benefit to electrification would be that virtually any source of energy out there can be made to generate electricity and deliver it to the grid (it’s a lot easier than jamming it onto a locomotive).  Therefore, the railroad industry would be shopping across all fueling commodities and methods in existence rather than being held hostage by a single commodity.

  • The Burlington Northern Railroad converted two SD-40-2 locomotives to run on natural gas and successfully ran them in revenue service from 1991 to 1995 on coal trains between Montana and Minnesota. The technology being used in the current CN program is the same as that used on the BN program: gas injectors and modified cylinder heads from Energy Conversions, Inc. that use early-cycle, low pressure injection of the natural gas and a pilot injection of diesel fuel to ignite the gas. Liquified natural gas was carried in a tender car that fueled two locomotives. The LNG was gasified on the tender cars. Full rated horsepower – 3000 HP – was obtained from each locomotive. The program ended because, at that time, diesel fuel prices remained low and natural gas prices were rising because of new gas-fired electric generating plants were coming on line. Now, however, the price per BTU of natural gas is significantly lower than the price per BTU of diesel fuel. If you would be interested in receiving my ASME paper on the BN natural gas locomotive program and/or the Los Alamos National Laboratory report on the relative safety of alternative locomotive fuels, please send me an email at srdit@aol.com.

    Steve Ditmeyer

  • I think SteveDittmeyer's approach is more appropriate for existing, predominantly diesel, locomotives.  The problem with David Foster's approach of generating electricity at central plants and "running trains on electricity" is that this requires an expensive catenary system and a fleet of electric locomotives,  Thus, this aproach  would be difficult to use except on the northeast corridor and electrically powered commuter/transit systems where catenary systems exist.

    I'm not an internal combustion engineer either (with a nod to HarveyK400), but converting diesel engines to run on natural gas seems to be a relatively well developed technique per the BN experience.  {I had an earlier experience of internal combustion engines running on "unorthodox  

    fuels" when we were met at the dock in Sendai, Japan by Japanese trucks with charcoal converters on the side shortly after the end of World War II.  Becxause of the shortage of gasoline they had developed a method of using charcoal to produce a fuel (gas) to use in the trucks' internal combustion engines.}

    Using natural gas on railroads would be much more practical than for cars and trucks on  highways.  First, the matter of fueling would be simpler.  RRs could have central fueling  points, perhaps in the dozens, compared to the "thousands" required with highway vehicles.

    It is assumed that RRs would use liquified natural gas (LNG) for which plants to liquify natural gas are being built in considerable numbers, primarily for the export trade.  Containers for LNG must be sturdily built and consequently are heavy.  This could be accommodated more readily on the "relatively few" locomotives as compared to the far more numerous highway vehicles.

    For these reasons, and those expressed by other commentators, the future for gas powered trains should be bright.  

    Harry Clapp