The locomotive builders—Electro-Motive Diesel and its new owner, Progress Rail Services (both owned by Caterpillar), General Electric, National Railway Equipment Company, MotivePower Division of Wabtec, R.J. Corman Railpower, Brookville Equipment Corp.—have introduced numerous green machines, both new and rebuilt, into the marketplace, and the railroads have been snapping them up. Gensets, hybrids, battery-electric, fuel cells, traditional but thoroughly tweaked and computerized diesel-electrics—the power of green is growing stronger with each advancement in technology.
Building EPA-compliant equipment boils down to choices and tradeoffs. The most challenging is the tradeoff between NOx, which tuning will address, and PM (particulate matter), which requires cleanup. Advancing ignition timing, though it improves fuel economy and lowers PM with better combustion efficiency, increases NOx. Retarding ignition drops NOx, but raises PM as combustion efficiency and fuel economy suffer. PM can be cleaned through use of a DPF (diesel particulate filter), and NOx can be lowered through an SCR (selective catalytic reduction), but again there are tradeoffs.
"There's not a lot of onboard space for extra equipment," according to R.J. Corman Railpower Chief Operating Officer Mitch Gillispie. DPFs and SCRs take up extra space, and have unique maintenance requirements. Favoring optimized combustion requires an SCR, which doesn't require maintenance, but does require replacement. A DPF, which uses a substrate material to absorb PM, is self-cleaning, but only to a certain degree. For high-horsepower road locomotives equipped with a large diesel engine, a DPF can be a massive, clumsy piece of equipment, but an SCR scales up better for a large engine. Tier 4 is intended to force after-treatment, as it requires a 90% reduction in NOx and a 93% reduction in PM from uncontrolled levels.
As with Tier 2, Tiers 3 and 4 will require most locomotives to meet standards on a long-haul line-haul cycle that emphasizes high-load operation, and a switch cycle that emphasizes idle and low-load operation. As well, locomotives complying with Tiers 3 and 4 must be equipped with idle reduction devices, either when new or before they are placed back into service after an overhaul. Engines must be shut down after a maximum 30 minutes idling, and can be restarted only to protect the engine, to keep batteries charged or compressed air supplies up, or to accommodate crew comfort or safety. Equipment that does this, along with the means to continuously monitor performance, is available from companies like Hotstart® Manufacturing, ZTR, Lat-Lon, Railhead, and Wi-Tronix. These suppliers and others have been able to combine their technologies.
The power of green will also depend upon operating a locomotive or set of locomotives optimally, and a host of systems to assist locomotive engineers has been developed.
"Freight trains are typically dispatched with enough locomotives in consist to make the 'ruling grade'—often resulting in surplus power for most of the trip, with trailing locomotives operating at the same throttle setting as the lead unit," notes EMD. The new EMD SmartConsist™ Fuel Management System "automatically sets each locomotive to its optimal throttle position, improving fuel economy, cutting emissions, and reducing noise in the lead locomotive. SmartConsist™ is fully integrated within the EM2000™ locomotive control system and its operation is transparent to the crew. The engineer simply selects the desired throttle notch in the lead locomotive, and the most fuel efficient power settings are activated for each unit. SmartConsist™ continuously monitors and sets the most fuel efficient combinations to achieve the required power and tractive effort.
SmartConsist™ "is suitable for both two- and three-unit locomotive consists, without unit isolation," says EMD. "Installation is simple and quick. It's required only on the lead locomotive to achieve savings from all units. Trailing units can be any vintage or manufacturer. It can be applied to the in-service EMD locomotive fleet and is offered as an option on all new EMD locomotives. SmartConsist™ offers fuel savings of 1-3% per locomotive in typical line-haul operation, extended overhaul cycles from reduced power settings, NOx and CO2 emissions reductions up to 3%, and added crew comfort with reduced noise in the lead unit."
GE Transportation's Trip Optimizer fuel management system is described as "an advanced energy management system that optimizes fuel consumption based on a specific train's makeup and route." It uses GPS, a digital track database, and advanced track algorithms that automatically learn the train's characteristics throughout the trip. It evaluates train length, weight, grade, track conditions, weather, and locomotive performance "to calculate the most efficient way of running the train while maintaining smooth train handling. It calculates a fuel-optimal speed profile for the trip and then automatically controls the throttle to maintain that planned speed. Train crews retain responsibility for safe operation of the train and can engage or disengage the system at any time." Trip Optimizer can be deployed on Evolution Series locomotives as a turnkey system, and can be combined with GE LOCOTROL® Distributed Power.
Invensys Rail Corp. and New York Air Brake (NYAB) are collaborating on locomotive systems that combine the fuel economy benefits of IRC's LFO™ (Locomotive Fuel Optimizer) and NYAB's LEADER™ (Locomotive Engineer Assist/Display Event Recorder). Together, the systems seek to optimize fuel economy and train handling in multiple-unit locomotive consists. LEADER prompts engineers to apply optimal throttle and brake settings for a given train consist and track profile. LFO then automatically makes individual throttle adjustments among the locomotives in the consist to optimize fuel efficiency based on total power demand. LEADER has produced fuel savings in the range of 8% to 12%; LFO has delivered average fuel savings of 3% to 4% in tests. The system is compatible with all EMD and GE locomotive models, features automatic calibration, and will work seamlessly with dynamic brakes and PTC. The combined systems can be installed on existing and new locomotives.
Plants grow into motive power
Soybeans, corn, rapeseed, panicum vergatim (switchgrass), Jatropha plants, sugar cane—as locomotive fuel? All of these plants can be processed into biodiesel fuel, which has been considered for many years as a partial substitute for traditional, petroleum-based diesel.
Citing concerns like the long-term effects on power assemblies and injector systems, the railroads and the locomotive builders have been extremely cautious with biodiesel. While blends like B-5 (5% biodiesel) are OK to use as far as warranties are concerned—"the engine barely knows it's there," says EMD Director, Engine and Engine Systems Design Marti Lenz—higher blends like B-10 and B-20 can be problematic. For example, since biodiesel is closer to alcohol than petroleum-based diesel, its has a greater tendency to absorb water contamination, which can occur in a locomotive fuel tank, and introduce corrosion problems. It can adversely affect engine deposits and wear, causing problems like piston ring blowby. Also, not much is known about its cold-weather effects.
Considering biodiesel's potential benefits—lower cost (aided by federal subsidies to farmers who raise the soybean and corn used to manufacture it, as well as user incentives) and potentially lower particulate matter emissions—is biodiesel worth pursuing? Could its benefits outweigh its potentially harmful effects? Can anything be done to lessen them?
There's only one way to find out, and that's through testing under actual service conditions. EMD and Norfolk Southern, in partnership with Archer-Daniels-Midland, are currently conducting a test program to study biodiesel's long-term effects. Testing, which will last up to one year, began in June in the Decatur, Ill., area. NS is operating eight SD70M-2s equipped with 710 engines in pairs, in captive service. Two pairs (four units) are fueled with a biodiesel blend; the others with straight diesel. Also, two MP15s equipped with 645 engines are operating, one with biodiesel.
"Our prime focus is on engine wear and deposits, the effect on lube oil, and cold-weather operation," says Lenz. "We started with B-11, ran it for three months, then went to B-15. We'll conclude with B-20, the most popular biodiesel blend. In terms of performance, horsepower so far is basically flat, and fuel consumption is up, but only slightly. We've seen a 2% increase in NOx emissions, but up to a 10% drop in particulate matter."
Justifying biodiesel means taking many factors into consideration. For example, one can argue that, since biodiesel comes from plants, and plants absorb atmospheric C02, railroad use of this fuel will contribute more to greenhouse gas reduction than railroads already claim using conventional diesel. All things considered, biodiesel may someday bolster the power of green.