Tech Insights

Electrifying Trains One Car at a Time

November 29, 2023 by Karen Hanson

A St. Louis company has developed electrified train cars that can operate independently and autonomously.

Intramotev, a startup based in St. Louis, is taking an innovative approach to electrifying freight train transportation. Rather than equipping the locomotive with electric batteries, it's creating individual cars that are fully electric and self-propelled. These cars are being implemented in an unusual place—a coal mine.


The ReVolt electric, autonomous train car.

The ReVolt electric, autonomous train car. Image used courtesy of Imtramotev


Iron Senergy recently acquired three of Intramotev's ReVolt train cars for use at its coal mine in western Pennsylvania. These battery-powered cars will help transport coal across Iron Senergy's private 17-mile rail line. Using the all-electric train cars will save on diesel consumption while cutting down on emissions at the mining site.


Battery-Powered Train Cars and Coal

The Cumberland Coal Mine in Greene County, Pennsylvania, is an underground mine that produces more than 6 million tons of bituminous coal each year. Much of its product is used to fire coal-burning power plants. Iron Senergy acquired the mine in 2020.

The coal extracted from the mine is taken by train via the 17-mile private track owned by Iron Senergy to Alicia Harbor on the Monongahela River. From there, the coal is loaded on barges.

Iron Senergy plans to use Intramotev's ReVolt train cars to assist with the coal transport along this private line.


Intramotev's rail car.

  Intramotev's rail car. Image used courtesy of Intramotev


The ReVolt car uses both batteries and regenerative braking, a technology that captures and reuses energy. Commonly used in hybrid and electric vehicles, regenerative braking can increase battery range by transferring electricity back into the batteries. A phone app is used to control and monitor the train cars.

Intramotev also makes TugVolt, which can be retrofitted for use on existing electric train cars. TugVolt can allow the car to decouple from the train and travel independently for the first or last mile of a trip. It also uses regenerative braking technology.

Three TugVolt cars are in operation at a mine in Michigan. A $200,000 grant from the Office of Future Mobility and Electrification in Michigan helped pay for their deployment.

Using the ReVolt cars is part of Iron Senergy's efforts to shrink its carbon footprint. The largest railway companies have also committed to lowering carbon emissions by 40% by the year 2030 by using several strategies, including electric power.


Trains, Coal, and Carbon

In the coal mining industry, trains have always been essential, both in carrying coal out of the mining site and in transporting it long distances for industrial and residential use. Transitioning to all-electric trains has the potential to reduce the use of fossil fuels and cut down on pollution.

The earliest trains used wood for fuel because the common variety of anthracite coal was too hard to be practical. A switch to softer bituminous coal in the 1860s led to widespread adoption of coal-burning train engines. It was a common sight until the mid-20th century to see a coal car hitched behind the engine of a freight train.


Engine with coal car, early 1900s.

Engine with coal car, early 1900s. Image used courtesy of Library of Congress


The trains burned coal to heat water which created steam to power the pistons of the locomotive's engine. It was an efficient but dirty business. The train created clouds of coal dust and pumped volumes of dirty smoke and carbon dioxide into the air.

By the second half of the 20th century, diesel had largely replaced coal as the primary fuel for train locomotives. Most trains today are powered by diesel with assistance from electric motors. Diesel fuels a generator, creating electricity to power the traction motors that turn the train wheels.


Video used courtesy of The Train Story


Diesel-electric is a step toward electric locomotives, but it doesn't eliminate the internal combustion engine that's the train's main power source. Although diesel produces a cleaner burn than coal, it still consumes fossil fuels and produces carbon emissions. Freight trains produce up to 35 million tonnes annually, according to a 2021 study.


Replacing Diesel-Electric Trains

Recently, Wabtec Corp. introduced the world's first heavy-haul electric train powered entirely by battery. The train was designed for Roy Hill, an Australian iron ore mining company. The locomotive will replace diesel-electric trains.

The train uses a technology Wabtec calls the FLXdrive battery system. The locomotive sports a battery capacity of 7 MWh, equivalent to 100 Model Ys electric cars by Tesla. Wabtec expects the system will lower emissions and fuel costs by more than 10 percent. The FLXdrive system also uses regenerative braking.

Still, the technology of battery-powered electric freight trains faces challenges similar to those of electric cars, specifically battery size and weight, range, and the risk of thermal runaway.