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DEVELOPING A HEAVY HAUL 21st CENTURY STEAM LOCOMOTIVE

Introduction:

Present projections indicate a decline in worldwide oil production after 2010. Much of this decline could be attributed to the decline in active exploration for new oil sources, a result of environmental laws in countries like the USA. Oil is a finite resource and supply reductions are inevitable, as will be future increases in the price of oil and its derivatives. Many industries such as transportation and synthetic textiles depend on oil, either as a fuel or as a raw material. Major changes can be expected to occur in the world economy as alternate fuel and energy sources come into wider spread use. Among the transport sector industries that will need to adapt to the expected future change, will be the railways.

Railways in an oil constrained future:

While electric traction is a well proven technology, it is not feasible for all railway applications. Electric traction incurs very high installation costs as well as accompanying infrastructure maintenance requirements and the accompanying costs. Electricity will be used along high density traffic lines and will be cost effective in such applications. As oil prices surge as a result of oil supply reductions, electric prices could also spiral as more transportation technologies adopt electricity as an energy source. In municipal transport, the trolleybus and the tram are well proven. Yet these technologies could compete for electric power with a host of battery and flywheel vehicles requiring a recharge, within the next decade or two.

The energy cost of electric railway traction could be expected to increase within the next decade and beyond, as the number of electric vehicles entering the market begins to increase. This possiblity requires that viable alternatives to electric railway traction from catenary or third rail, be explored. Fuel cell locomotives may be an option. Fuels such as hydrogen and natural gas may be used as fuels.

Fuel Cell traction:

Fuel cells may come into urban railway use, yet have some drawbacks at present for heavy haul use. The proton exchange membrane fuel (PEM) operates at an efficiency of less than 40% and requires hydrogen as its fuel source. A stack of PEM fuel cells in a 6,000-horsepower locomotive could cost well over $9US-million. Water releases hydrogen via electrolysis at an efficiency of 67%, using electricity . . . . for an overall efficiency of 26% from the electrical supply to the locomotive drive wheel. If the electricity is being supplied by a thermal power station operating at 50% efficiency, this reduces the hydrogen PEM fuel cell locomotive to 13% from the thermal energy source to the locomotive drive wheel and under highly ideal conditions. An overall efficiency of 11%-12% would be more common, from the heat source to the drive wheel.

In Argentina, L. D. Porta modified some 2-8-0 and 2-10-0 steam locomotives on the Rio Turbio narrow gauge rail line, using improved exhaust (the Lempor ejector), improved insulation, modification to the valve timing and to the coal combustion (using low grade coal), to operate at an in-service efficiency of 12%, going as high as 15% under very ideal operating conditions. It has been speculated that a compound steam locomotive using such modifications could deliver 15%-18% efficiency in service, while a triple expansion compound steam locomotive could exceed 20% operational efficiency from heat source to drive wheel. This level of efficiency would even be possible if the steam locomotive was a fireless cooker, using latent heat of fusion in a thermal storage tank, sourcing its heat energy from garbage(rubbish)incineration, geothermal energy, solar thermal energy, or eventhe waste heat of the same thermal power station from which the fuel cell locomotive sourced its electricity for its hydrogen (electrolysis of water).

The high costs of fuel cells will serve to make other locomotive concepts very competitive, in hauling heavy trains along relatively low traffic density lines involving high tonnage trains. In this type of operation, where infrequent high tonnage trains operate over long distances, the lower cost of steam traction could become an advantage over an all electric system using overhead trolley cable, or a fuel cell locomotive. In the late 1980's, the London School of Economics evaluated the costs of new generation steam against diesel and all-electric operation . . . . . . . . . and the research indicated that steam traction would have an economic edge. In the USA, during the mid 1980's, the Burlington Northern Railway evaluated the costs of converting their heavy coal lines to all electric against modern steam power . . . . . . . . and modern steam power again showed that it offered a cost advantage. The proposed steam locomotive was designed the the American ACE group.

QUAD-TURBINE HEAVY HAUL STEAM LOCOMOTIVE

Background:

Over the past 2-decades, several proposals for new generation steam locomotives have come forward. One of the most impressive proposals was put together in the USA by Ross Rowland's ACE (American Coal Enterprises) group, which endeavoured to discover what would result if all the advances in thermodynamics which developed after the demise of mainline steam traction from the world's major railways, were incorporated into a modern concept. Advances such as using a fluidized bed of coal, catalytic exhaust convertors, a purified water recycling system incorporating a cooled multi-expansion valve to convert low pressure exhaust steam into hot water (for cooling in a Henschel type radiator), were among the advances. The ACE locomotive concepts were still based on 2-stage compound expansion of steam, offering potential efficiencies as high as 27%.

In Australia, a concept for a triple expansion garrat steam locomotive came about in 1995, proposing to use a 900 psi boiler. The piston/cylinder system for this locomotive would have had to have been custom built, at cosiderable cost. In the USA, an associate of the ACE group, Shoemaker, proposed a 9,000-horsepower steam turbine electric. Not much is known about the proposed turbine system, outside a select group. Potential fuels for these locomotives included compressed natural gas, coal-synthesised fuel, coal slurry combustion (a technology developed in Sweden) or fluidised coal bed combustion. These concepts can be taken further.

Quad Turbine system:

In 1989 a concept of a new generation fireless cooker was shown to the US DOT Federal Railroad Administration. Than concept used a triple turbine, in a 1-2-4 power ratio and yielding 7-equal step power increments, each operating at maximum turbine efficiency. As further research was periodically undertaken on that concept, the triple turbine concept gave way to a quad-turbine system in a 1-2-4-8 power ratio. The research into a new era fireless cooker (rechargeable stored thermal renewable energy system) was applicable to many related areas. It can be combined with research undertaken by L. D. Porta, David Wardale, Phil Girdlestone, Ross Rowland's ACE group, Shoemaker's Group, Dr. John Sharpe's research, the Swiss DLM group, as well as the Australian Steam Locomotive research group.

Two quad-turbine systems are henceforth suggested, both using commercially available steam turbines. Turbines of 750-Kw, 1500-Kw, 3000-Kw and 6,000-Kw are commercially available, yielding a total of 11,250-Kw or 15, 000 horsepower, with a combination giving 15-power settings, all at maximum efficiency. Turbines are sold on the basis of their output, as are the alternators the turbines would drive. The quad turbine system would cost more than a single 11,000-horsepower turbine driving a single, large alternator. The single large turbine would run into the classic part-load loss of efficiency, which would cause fuel costs to skyrocket. The savings in fuel costs in heavy haul rail operations would enable the added cost of the quad-turbine in a 1-2-4-8 power ratio, to be recovered within 12-18-months of operation.

The smaller quad-turbine proposal would require a small turbine of 500-horsepower (375-Kw), to operate along with the 750-Kw, 1500-Kw and 3000-Kw turbines shared with the larger locomotive. All combined, the maximum output of the smaller locomotive would be 7500-Horsepower, with 15-power increments in 500-horsepower steps from 500-hp to 7500-Hp. The smaller locomotive would be more versatile due to its smaller power steps, all at maximum efficiency, yet it would share main componentary with the larger, more powerful, extreme heavy haul concept. Both sizes of locomotive could be maintained in the same repair shop, by the same personnel. Traction would be via electric motor mountain in conventional railway bogies/trucks . . . . again, conventional equipment similiar to the system proposed by Shoemaker.

A variety of fuels could be used in these locomotives, including combustion of coal slurry (developed in Sweden), fluidised bed of coal, natural gas(in conjunction with solid oxide fuel cell technology), coal-synthesised fuel, solvents that are unsuitable for use in an internal combustion engine as well as oils that art similiarly unsuitable for use in internal combustion systems. One of the DLM modified steam locomotives demonstrated that for equalpower output as a modern diesel locomotive, its exhaust could be 80% cleaner . . . on a single-stage two-piston locomotive. A modern quad-turbineheavy steam locomotive could also become enviromentally competitive against contemporary diesel power.

Thermal Energy Storage:

Both locomotives would borrow technology developed by L. D. Porta, the DLM group, ACE Enterprises as well as thermal energy storage technology. Thermal storage tanks would be incorporated into both locomotives, to enable short term power output increases without increasing fuel consumption or exhaust emissions. The thermal "battery" would operate on latent heat of fusion of a multi-metal-oxide or comparable compound. It would serve a second purpose: rapid restart of a locomotive that has been out of service for several hours, even days.

A locomotive could finish its last run on a Friday evening and not be required to be back in service until early Monday morning. Experience with a new steam locomotive built by DLM in Switzerland, has revealed that the modern insulation is so effective, that the locomotive is ready for serve within 10-minutes after its fire is lit, after being out of service during an overnight layover. The DLM locomotive also incorporates an electric element for rapid warm-up, a concept well suited to a small locomotive.

A large locomotive could borrow fireless cooker componentry to enable economical reheating. Example, an out of service new generation heavy locomotive could be parked on a track near a thermal power station. Waste heat from the thermal power plant could be used to maintain heat in an out-of-service steam locomotive, in much the same manner in which a traditional fireless cooker is recharged. Maintenance heat could also be sourced from a solar thermal source, a geothermal source, incineration of refuse (garbage) or from a timed natural gas supply. Hence, a thermal storage tank as well as a heat exchanger line would be standard equipment on a modern quad-turbine steam locomotive. One of the drawbacks of traditional steam motive power, its long warm up time (7-9-hours) after a fire relit, could be resolved and reduced to a 10-minute locomotive warm-up, prior to re-entering service . . . . . . and increasing the locomotive availability for service.

Boiler washdowns:

Traditional steam locomotives required almost daily boiler cool downs and wash downs, due to scale build up. L. D. Porta in Argentina reduced this to twice annual boiler wash downs, by using a water purifier system. Purified water operating in a system proposed by Ross Rowland's ACE group, could reduce boiler washdowns to a once annual event. This is a modified Henschel system, developed by Henschel for the trans-Karoo 4-8-4 steamers used by South African Railways. Hence, another major drawback of the traditional steam locomotive, can be resolved.

Smokebox/firebox maintenance:

The smokebox and the firebox were major, labour-intensive items in traditional coal burning steam locomotives. Advances in coal combustion, such as the fluidized bed of coal and the combustion of coal slurry, can greatly reduce soot build up in the firebox. L. D. Porta's work as well as that of the ACE could greatly extend the in-service times of future steam locomotives. The quad-turbine locomotive could also be developed into a multi-fuel, or flexible fuel concept. This would give it an advantage over the internal combustion engine presently being used in diesel locomotives, as well as aid in extending firebox/smokebox maintenance intervals. Developing multi-fuel flexibility into steam turbine electric locomotives could greatly enhance their marketability in the future.

Conclusions:

There is much good research that has been undertaken over the past 20-years by a variety of people, to develope the steam railway locomotive of the future. -The steam locomotive could evolve into a multi-fuel/flexible-fuel competitor to existing diesel traction. The internal combustion engine has limitations in mulit-fuel operation, while a steam system has a much wider fuel tolerance range. Future steam locomotives may have a much wider fuel tolerance range than various proposed fuel cell options. -The componentry to build steam-quad-turbine-electric locomotives is presently and readily commercially available, as are the spare parts and at competitive prices. The cost of building such locomotives can more easily be justified in high-power, heavy haul service (over 6,000-Hp), including intense heavy service (12,000-Hp), than in lighter duty service. It may be possible to develope fireless cookers to become competitive in the lighter duty service market, where extreme fuel flexibility combined with minimal maintenance requirements, in service along non-electrified lines, are the factors which will make the concept attractive. -The concept of a quad-turbine-steam system is but another option in the research to develope a viable future steam locomotive. It borrows heavily from previous research and hopefully will serve as a stepping stone to undertake further research into refining the future steam locomotive into a viable, attractive and competitive concept.

*Harry Valentine
. Transportation Researcher,
November 2000.

*Researched the triple-turbine fireless cookers of the late 1980's . . . . . .
US Federal Railroad Administration
at the time commented on the concept
(Iraq had declared war on its neighbours and the oil supply was threatened).

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