GenSet Design Collaboration Produces Revolutionary New Switcher

In 2004, Union Pacific (UP) saw the need for a new generation of yard switchers and approached National Railway Equipment Company (NREC) of Dixmoor, Illinois to design one to fit their needs. Jim Wurtz, NREC’s Vice President of Sales and Marketing, has no doubts about how well they did the job.

“It will change the face of the railroads,” Wurtz said in an interview with G&FM.

The term “genset” is derived from “generator set,” referring to the pairing of a diesel engine and a generator. NREC’s genset locomotive, the N-ViroMotiveTM, uses one, two or three of these sets, depending on the tasks the locomotive is assigned to. The prototype switcher designed for Union Pacific was equipped with two engines, each able to provide a constant 700 horsepower. In production switchers, one genset is used in light duty units, two for heavy duty switchers and three are used in four axle branch line locomotives.

NREC’s gensets use a 19 liter Cummins diesel engine that shares technology with the diesels used in semi trucks. As Wurtz puts it, the engine has “a truck genealogy,” but was originally designed for electrical power generation. “Cummins had the only [EPA] Tier III certified non-road engines in the size we needed. We wanted a more robust engine for this unit than we could get anywhere else.”

“UP brought us their needs and we designed the unit to meet them. It’s a great example of a supplier and a customer working together,” Wurtz said.

One of UP’s problems—one they share with the other Class 1 railroads—is that their four axle locomotive fleet has changed little since the 1950s. Wurtz discussed the reason the fleets needed an update: “[Switcher] production effectively ceased in the mid-80s…For Class 1 railroads, the majority of capital [for power units] has been going to the six axle, 4400hp locomotives you see pulling long trains.” As a result, he says, switchers and branch line locomotives are typically “long in the tooth.” As increasing fuel prices push a greater share of freight business from the trucking industry to the railroads, more pressure is put on the four axle fleets.

Perhaps more urgent were environmental concerns. UP would need to comply with new emission targets set by the EPA and the California Air Resources Board (CARB) beginning this year, with another set of targets going into effect in 2007. Regulators had begun by requiring emissions reduction in cars, then in heavy duty trucks and lastly moving on to trains. “This was not a top concern just five years ago,” Wurtz said, but a combination of new laws and a desire to be better corporate citizens has convinced railroads to reassess their four axle fleets. Fortunately, NREC and other manufacturers will be able to benefit from the low emissions technology developed for tractor trailers.

The N-ViroMotiveTM includes a number of new features, each of which is a major improvement over the previous generation of switchers.

  • The switchers are remarkably quiet compared to traditional locomotives, sounding much like a tractor trailer. Wurtz noted that it’s possible for the operator to be in the cab with a single engine engaged and not be able to hear it running.
  • The N-ViroMotiveTM meets or exceeds all rail emission standards and is certified by CARB as an Ultra Low Emissions Locomotive.
      • End users can expect fuel savings of at least forty percent and at least an eighty percent reduction in emissions of nitrous oxide compounds. According to Wurtz, about half of the fuel savings are from greater engine efficiency. The genset engines operate at about twice the rpm of the previous generation of locomotives, resulting in greater efficiency and lower emissions. The N-ViroMotiveTM meets or exceeds the most stringent EPA and CARB targets.

        The remainder of the fuel savings is a benefit of the N-Limit system, which monitors idling. If any engine has been at idle for more than a set period of time, the N-Limit system shuts it down.

      • Genset locomotives have higher unit availability than older units. Frank Pezel, NREC’s General Manager of Operations at their Dixmoor, Illinois headquarters, explained that between clearing out test cocks, prelubing the engine and other procedures, restarting a traditional EMD switcher would be a 30 to 45 minute process. If the EMD has been sitting for 48 hours or more, that stretches out to an hour and a half, Pezel said. For this reason, traditional locomotives are often left at idle for long periods of time to avoid the wasted time consumed by a restart. In contrast, the diesels in an N-ViroMotiveTM can be cranked up as quickly as a truck motor. Long idling periods are also avoided by using a glycol coolant system that allows the unit to be shut down in temperatures 20 degrees Fahrenheit and up.
      • Unit availability is also increased by the skid mounting of the individual gensets. The skids allow the gensets to be removed with a forklift, and the system is designed with quick-disconnect couplings. “With the quick-disconnect couplings we’re looking at an hour and a half—that’s the top end–to remove the skid and about 2 hours to reinstall,” Wurtz said. “With an EMD you would need 160 to 210 man hours to remove and reinstall the engine.”
      • Longer engine life is achieved by using a load sharing system which evens out the wear and tear on the engines. The system tracks the hours each genset has been working, and assigns work to the motor with the shortest amount of hours.
      • End users will also find that a given N-ViroMotiveTM delivers more power than its listed rating. In fact, Trains Magazine reports that Union Pacific expected their 1,400hp N-ViroMotiveTM prototype to perform as well as a 2,000hp EMD GP38-2 in yard switching tasks. This is due to NREC’s use of a European innovation: individual traction motor controllers. In a traditional switcher, controllers respond to slippage by reducing power to the entire truck assembly where the wheel is slipping, cutting the unit’s power in half. The traction controllers in the N-ViroMotiveTM affect only the motor that is slipping, preserving more of the power and providing a 50% increase in adhesion. This power increase has a practical, even visible, effect. Wutz gave the example of three locomotives pulling a long train. “You would only need two of these engines to do the same work,” he said.
      • The N-ViroMotiveTM is also equipped with the SS5506 fuel tank, which will not spill fuel in the case of a derailment.

NREC will deliver 30 of the locomotives to UP this year and 30 more in 2007. The switchers will be used at yards in the Los Angeles Basin. Wurtz said NREC has received inquiries from “other Class 1 railroads as well as short line and industrial accounts, and some organizations outside the U.S.” NREC is also building a demonstrator unit that can be loaned to potential customers for trials, which should be completed by August.