By Eric Berger
A new entry has appeared in the drive to develop an environmentally-friendlier locomotive and it features an eye-catching appearance that is different by design. OptiFuel Systems has announced plans to test a prototype road locomotive and powered tender fueled by Renewable Natural Gas that will be capable of producing combined power up to 7,500 hp.
The U.S. Department of Energy defines RNG as an advanced biofuel and a “pipeline-quality gas that is fully interchangeable with conventional natural gas” and which “can be used as a transportation fuel in the form of compressed natural gas or liquefied natural gas. It is sometimes referred to as biomethane, a biogas purified of non-methane components, derived from decomposing organic material.
Anticipating a growing market for road locomotives that meet increasingly tighter emissions restrictions, Optifuels said its “locomotive will have ZERO Well-to-Wheel nitrogen oxides and particulate matter criteria emissions and Negative Carbon Intensity while simultaneously improving fuel cost and operating range by 25 percent.”
The locomotive units are rated at 5,100 hp with 5,600 hp peak capability, while the traction motors under the tenders provide another 2,500 hp. The compressed storage capacity of the tenders is 10,000 Diesel Gallon Equivalence.
“Honestly, I thought we were just going to prove out a concept,” said Scott Myers, president and CEO of OptiFuels Systems, referring to a USDOE contract awarded in 2020. The result of that work is a new DOE contract that takes the concept and the company to a new level. “Now we are in the pre-production phase for ten locomotives.”
OptiFuels Systems has been getting practical experience in the design and operation of natural gas systems in locomotives for more than a decade, including a partnership with Indiana Harbor Belt. The company says the RNG units they are building will offer an alternative to diesel that can outperform rival technologies such as battery-electric or hydrogen in terms of providing sustained power for long periods of time.
The prototype RNG locomotives and tenders are being constructed in Texas this year with testing scheduled to begin in January 2025, in Pueblo, Colo., at the Transportation Technology Center. After that, ten locomotives and five tenders are scheduled to embark on a one-million mile testing program on railroads across the country beginning in January 2026. The company hopes to begin production of the locomotive in 2028.
It is no accident that the artist’s rendering of the OptiFuels road unit bears a resemblance to the streamlined passenger engines of an earlier era. “We want to stand out as something different,” Myers said. Beyond its aesthetic qualities, the design incorporates the aerodynamic principles that shaped the original streamliners for the same reason, reducing drag and increasing efficiency, he explained.
The units will be all new from the ground up with the exception of truck frame castings, which will come from scrapped EMD SD units. “They will be completely rebuilt, of course, and will be equipped with CAF traction motors,” Myers told Railfan & Railroad. He said they originally planned to build the units on recycled 74-foot EMD SD40M frames, but ultimately decided to produce new frames engineered to perfectly accommodate the various components of the locomotive. The design features a high degree of modularity, intended to provide relative ease in routine operations, maintenance and repairs. The design also permits buyers to choose from a variety of subsystems and suppliers.
