A discussion of propulsion options for freight rail is offered by seasoned locomotive mechanical engineer Michael Iden, a former mechanical department officer with Union Pacific, offering insight from his years of practical experience with new technologies and research and development.

As the railroad industry moves toward decarbonized propulsion, it’s critical that we start looking analytically at each technology and supporting infrastructure, and begin developing the comparative economics. We’re talking, in this article, about hydrogen fuel cells and propulsion batteries (plus one very mature technology that continues to be “written off,” and a unique variant).

Managing technology is never easy, and new technologies always introduce a sometimes unclear mix of benefits and risks. Borrowing an adage from carpentry: “measure (at least) twice and cut only once.”

Our industry has been dieselized for 63 years (Class I steam died May 7, 1960), having evolved from the steam-to-diesel transition (1940-1960) plus a previous decade-plus of research, trial and error. Coal as locomotive fuel was often 10% of all carloads. The infrastructure was massive and labor-intensive. A single steam locomotive could consume 90,000 gallons of water between New York City and Chicago. The transition to diesel was a classic example of disruptive industrial innovation with positive and negative impacts on railroads, employees, stockholders, suppliers and communities.

Railroads did become more productive; today, they produce 63% more work (gross ton-miles, GTMs) annually using only 1/9th the equivalent energy as they did in 1945, steam’s peak.

Upfront disclosure: As a trained professional engineer, I believe there will be valid applications for both hydrogen fuel-cell and battery-electric locomotives, but neither is a “one size fits all ‘silver bullet’ solution.” Also, I’m not giving up on diesel engines, as they could be hybridized by adding propulsion batteries (a separate discussion for another time).

This is very clear: Decarbonized grid electricity will increasingly be our primary energy source. Clean renewable electricity (some call it a trillion-dollar national investment) will manufacture hydrogen and recharge batteries. But it can also power electrification of selective heavy-density routes. We cannot dismiss any option without a factual assessment. The business cases for hydrogen and batteries should be prepared and compared to the case for electrification (along with a business case for a unique variant offering faster cash payback).

Another reality: The “pull any train on any railroad” diesel locomotive will gradually be supplanted or possibly replaced, by new technologies. New-technology locomotives may not be common or interchangeable when introduced, and completing rail decarbonization will likely take 15-20 years (the 2050 target for net-zero carbon is only 26 years away!). Fuel cell and battery-electric locomotives will be “corridor and infrastructure limited” until thousands of such new units are in service, drawing attention again to infrastructure requirements and comparative energy efficiencies.

To read the whole article, please go to https://www.railwayage.com/mechanical/locomotives/follow-the-megawatt-hours-hydrogen-fuel-cells-batteries-and-electric-propulsion/