The image of trains used to include pictures of sooty firemen shoveling coal into glowing hot fireboxes.
Today, scenes like that are relegated to railroad museums and steampunk fantasies, as diesel-electric trains long ago became the standard.
But Davidson Ward thinks steam engines may still have a place in the 21st century.
Ward is a co-founder of Sustainable Rail International, a nonprofit that recently partnered with the University of Minnesota to retrofit a 1937 steam locomotive to run on a carbon-neutral coal made from biomass.
“It’s relatively radical in the rail industry in the United States to say that steam engines might be a logical way to go,” Ward said.
Why steam engines?
Ward and his project partners believe biomass-powered steam engines could play a useful role in regional rail networks, as well as in the developing world.
Their preliminary research shows biocoal trains could be less expensive to fuel and maintain and quicker to accelerate than diesels.
The project, known as CSR Project 130, aims to break the steam locomotive speed record — 130 miles per hour — within two to five years.
Ward approached the university about a year and a half ago to see if it could supply a biofuel to power the steam engine. Shortly after that they began working with Rod Larkins, special projects director for school’s Initiative for Renewable Energy and the Environment.
The fuel they arrived at is a torrefied biomass, or biocoal, made from cellulosic plant material. The biocoal is similar to coal in its energy density and material properties, but it doesn’t contain any heavy metals and produces less ash, smoke and volatile gases. It’s potentially carbon neutral, too, depending on how the material is harvested.
It’s process used to make the biocoal is 96 percent efficient — only 4 percent of the material’s energy is lost in the conversion. It’s also relatively simple and inexpensive, Ward said.
“Having a solid fuel facilitates one fewer step in the energy conversion process. We don’t have to take a solid and gasify it, or take a solid and gasify and liquify it,” Ward said.
So far they’ve just produced the fuel on a small scale. It’s more expensive than coal, but they believe it can be a cheaper alternative to diesel, even when considering for the fact diesel engines run more efficiently.
A carbon tax or penalty would make the fuel more competitive, but Ward said it’s not a product that’s going to have to depend on subsidies.
A rolling museum
To demonstrate the potential, the team will spend the next few years retrofitting an antique steam locomotive, which it acquired in November from the Great Overland Station Museum in Topeka, Kansas.
The locomotive was built in an era in which many were designed to switch between coal and oil depending on the price of the commodities. The CSR Project 130 team will add a third fuel to its capabilities: biocoal.
The coal-burning locomotive boiler is a good fit for biomass, Ward said, because unlike internal combustion engines it can handle a wide range of fuels with different energy density. The amount of energy in the biocoal will vary depending on the plant material it was made from, but all operators need to do is add more or less of it to adjust for the differences.
“It’s such a simple system,” Ward said.
The range of their train will be limited to a few hundred miles round trip, which means its real-world applications in the United States would most likely be limited to regional commuter rail.
The engines’ simplicity, though, make it a potentially broader solution in the developing world, where it isn’t easy to find replacement parts for broken diesel generators, for example, Ward said.
“You can actually fix these things because they’re simple to maintain,” Ward said.
The team plans to move the locomotive from Topeka to Minneapolis in the next year, and after that it will begin a full engineering review of the engine. When they finish retrofitting the engine — within two to five years, depending on funding availability — it won’t have any of the comforts of a modern commuter train. A real-world prototype would be the next phase.
The first step is showing steam engines can be relevant today. Ward makes an analogy to wind turbines, another centuries-old technology that we recently embraced again.
“They’ve been modernized and are now ubiquitous across the landscape,” he said.