Leaves cause major rail problems - how the MBTA is using a new laser to fix this

MASS. — Every fall, raking and clearing leaves is a chore every homeowner knows all too well.

For the MBTA, fallen leaves aren’t just a nuisance — they’re the culprits behind a problem known as “slippery rail,” which can damage train wheels and lead to service delays.

Boston 25 Traffic Anchor Catherine Parrotta met with MBTA Chief Operating Officer Ryan Coholan along the commuter rail’s Fairmount Line to learn more about the issue.

Coholan says slippery rail season peaks from October through November, when warm days and cool nights create condensation on the tracks.

“When that moisture mixes with those crushed leaves, it creates a substance called pectin,” Coholan explained.

“When you have a steel wheel on a steel rail, that pectin acts like a lubricant.”

To fight the problem, the MBTA built its first wash car about 15 years ago.

“It was essentially a pressure washer mounted on a flat car with a tank car — about 30,000 gallons of water — and it was pulled by two locomotives,” Coholan said. “They would work at about three to five miles an hour. It’s very slow.”

Two newer wash trains have since been added. They’re faster, more powerful — and last fall, the T deployed something even more efficient: a laser train.

“The laser was built out of a surplus single-level coach,” Coholan said. “The interior is loaded with all of the operations equipment, transformers, power systems. And then the actual laser heads are mounted underneath the car.”

The laser train runs alongside scheduled service and can clean 50 to 60 miles of rail per hour. On the Fairmount Line, the only hint of its presence was its purple-and-black exterior as it sped past.

And while this part of the city might not seem like a hotspot for slippery rail, Coholan says it’s more vulnerable than people think.“

It’s funny because, certainly, behind me you see the city skyline. As I’m looking behind you, I see a tunnel of trees,” he said. “And trains, as they’re going 50, 60 miles an hour back and forth, will pull all those leaves with them.”

The laser train burns off the leaf residue, sending a faint cloud drifting behind it. According to Coholan, the laser train and newer wash trains together can clean about 200 miles of track per day.

The T also uses snow fences in some open areas to keep leaves from blowing onto the rails — a much easier task than reshaping wheels damaged by slippery conditions.

While slippery rail season will end soon, Coholan says preparations for next year are already underway.

“We want people to know that we don’t just sit back and say, ‘Well, this will go away,’” he said. “We try to be as proactive as possible to make sure that we can keep moving people.”

This is a developing story. Check back for updates as more information becomes available.

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