The Union Pacific Railroad has ordered 98 diesel-electric hybrid RailPower road switcher locomotives for use in Texas. The locomotives are estimated to provide fuel savings of 20% to 40% with reductions in NOx and particulates of about 80%. The locomotives are designed to reduce fuel usage in road and branchline switching operations where locomotives use up to three times the amount consumed by yard switchers. Union Pacific will apply its recent $81 million dollar award from the Texas Emmisions Reduction Plan towards the purchase of these locomotives.
The locomotives are powered by large banks of batteries connected to the hybrid power-train. When the batteries start to become depleted, the clean-burning diesel engine kicks in to power a generator to recharge the batteries. The hybrid locomotives are the world's largest and heaviest hybrid vehicles in production.
This order is for 80 triple-genset and 18 twin-genset RP series switchers. In August Union Pacific purchased 10 hybrid yard switchers for use in California from Railpower. In March, the Canadian Pacific Railway said it would buy as many as 35 hybrid locomotives from RailPower over a four-year period.
Hybrid technology is ideal for locomotives, due largely to the absence of weight constraints. Switchers are deliberately designed to be heavy to gain maximum traction and they operate in an inefficient 'stop-go' manner that is hard on the large engines of conventional units. Unlike traditional switching locomotives, the hybrid switchers have very small diesel gensets, large banks of long-life, recyclable batteries, and do not idle.
Railpower currently has two main product lines: hybrid yard switchers in the 1,000-2,000 horsepower range and hybrid yard and road switchers in the 2,000 horsepower range. The traditional drive train is replaced by a large battery bank and small generator set(s) ("genset") consisting of Tier 2 compliant diesel engine(s) and an electrical generator: typically a 90 to 200 kW genset (480 V, 3 phase rectified to DC). The yard switchers have one genset and the road switchers two or three gensets. The genset is generally run at a constant speed in the on-off mode for maximum efficiency. This electricity is then used to replenish a large bank of rechargeable lead-acid batteries which are, in turn, connected to the traction motors that power the locomotive. The batteries are kept at an optimum state of charge by the genset.
The main battery consists of latest technology valve-regulated lead acid, AGM type batteries. The battery, specifically designed by RailPower, is maintenance free, has a long battery life, and high round trip efficiency. The added weight of the battery helps to improve the tractive effort or "pull" of the locomotives and the ability to use large heavy batteries with lots of capacity is a key advantage to locomotives in contrast to the automobile industry where weight is a major issue and batteries need to be designed to be as light and energy dense as possible.
Headquartered in North Vancouver, British Columbia, Canada, RailPower has its principal engineering management facility in Erie, Pennsylvania.
Thanks to Clean Break for its Oct. 14th lead on this post.
"Union Pacific Railroad to buy 98 Road Switcher Locomotives for Texas", press release, RailPower Technologies Corp., Oct. 13 2005
Railpower Technologies Corp., Vancover, British Columbia