FRA study sees new locomotive tech as gateway to electric freight trains

The agency that oversees the U.S. rail network thinks it has a plan to help freight trains switch from diesel to cleaner and less expensive electric power.

A Federal Railroad Administration study on mainline electrification recommends that the industry develop a prototype dual-mode freight locomotive and battery tender that could test the feasibility of leaving cost-saving gaps between sections of overhead catenary.

North American freight railroads have studied electrification but have always reached the same conclusion: Stringing wire over every mile of main line is prohibitively expensive and poses a colossal financial risk. But the most recent of those studies is 45 years old.

“Freight rail electrification has not been implemented to date by U.S. Class 1 railroads because of various economic, technical, and institutional barriers,” the report says. “The primary barriers to freight rail electrification were found to be its high up-front capital costs, high risks due to the uncertainty of electrification in the North American context, and the presence of alternative investments that carry less risk. Over time, changing technology and a shift from using electrification to reduce energy costs to using it to reduce emissions have potentially altered the impact and relevancy of some of these barriers, and created pathways to overcome them.”

The FRA study, released last month, notes that locomotive technology has changed considerably since the completion of the last known Class 1 railroad electrification study in 1980. Chief among those changes are the shift to AC power and rapid improvements in batteries.

“Dual-mode or rapidly improving battery electric locomotive technologies could potentially navigate gaps in electrification and eliminate the large expense of raising clearances under bridges or through tunnels,” the report says. “Unlike the DC traction locomotive models considered during earlier electrification studies, modern high horsepower AC traction locomotives could be readily adapted into electric locomotives during an interim operating phase, changing the locomotive replacement costs and potentially delivering earlier benefits.”

Among the locomotive options the report considers:

• Converting existing AC-traction, diesel-electric locomotives to full electric instead of purchasing new electric locomotives.
• Pairing AC-traction, diesel-electric locomotives with tenders that either house batteries or use a pantograph and transformer to tap catenary when available, but run on diesel when overhead power is not available.
• The development of dual-mode freight locomotives that can operate at full power either as diesel-electrics or straight electrics.

“A research program to convert an existing AC traction locomotive to a dual-mode electric platform, develop an electric power tender, and investigate their combined performance and efficiency on an electrified test track could substantially reduce uncertainty in the cost of implementing intermittent electrification and its associated risk,” the report says.

Candidates for conversion would include Wabtec/GE AC4400, ES44AC and ET44AH models as well as the Progress Rail SD70MAC and SD70ACe, the study said. Representatives of locomotive manufacturers Wabtec and Progress Rail did not respond to FreightWaves’ requests for comment on the study.

New Jersey Transit currently operates Bombardier dual-mode diesel-electric locomotives between New York City’s Penn Station and outlying suburbs. 

As for catenary, the report identified three important ways of bringing down initial costs of electrification.

First, intermittent electrification — or leaving gaps between catenary — would shave installation costs.

Second, railroads could partner with electric utilities to share risks and benefits of electrification projects. Railroad rights-of-way could host electric transmission lines — giving utilities a far easier way to build new power lines from generating stations to metropolitan areas — that also could power catenary.

Electrification of trunk freight lines is not without precedent. The Chicago, Milwaukee, St. Paul and Pacific Railroad (“Milwaukee Road”) operated 645 miles of overhead catenary in mountainous territory between Idaho and Montana, and in Washington state. The Pennsylvania Railroad maintained a vast network under wire along the East Coast. Only the PRR’s catenary survives, for passenger trains on the Northeast Corridor.

And, finally, railroads could seek public funding to aid in their decarbonization efforts.

The Association of American Railroads says stringing wire over freight main lines is a no-go.

“Our position remains that overhead catenary is an unviable option for the nation’s freight rail network for a variety of reasons — including exorbitant costs,” spokeswoman Jessica Kahanek said.

The authors of the FRA study say more research is necessary.

“Dual-mode locomotives for freight service and intermittent electrification are two important approaches to improve project economics, but both require further research to prove their technical feasibility and determine more specific costs. Implementation strategies that include utility lease agreements for co-locating transmission lines in railroad right-of-way (ROW), or government partnerships or grant programs to capture the value of public health and climate benefits, offer the most promising pathways for improving freight rail electrification economics,” the report said. “Transferring some of the initial capital cost and risk of freight rail electrification from freight railroads to utilities and public agencies is critical to achieving freight rail decarbonization. Overall, several promising technologies and implementation strategies, taken together, offer a modern approach to railway electrification that is potentially more feasible than traditional electrification.”

The report also created a new economic formula that can be used to perform a cost-benefit analysis of proposed electrification projects.

It also notes that some technical and operational challenges must be overcome for electrification to become practical. Existing track circuits, for example, are DC and would need to be converted to AC. It’s also unclear how positive train control systems would interact with overhead current. The common use of midtrain distributed power, meanwhile, would greatly complicate engine changes at the end of electrified territories.

The FRA study, “Cost and Benefit Risk Framework for Modern Railway Electrification Options,” was authored by C. Tyler Dick and Rydell D. Walthall of the University of Texas at Austin, locomotive expert Michael E. Iden, and railroad economist James R. Blaze.

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