It’s perhaps hard to think of leaves as the reason for thousands of hours of transit delays (and probably millions of dollars of economic damage). But that’s the reality for train operators the world over.
When leaves fall on the line, they’re squelched into a mulch that eventually hardens into something very slippery and hard to remove. The result is that trains lose their ability to stop as quickly as they would normally (this is not good), and operators are sometimes forced to shut down lines while they remove the material.
In the U.K., companies use high-powered water jets that sit at the front of trains and break apart the substance as they move along. But engineers in the Netherlands think they can better that method. They’re looking into lasers, like the one here:
Three Dutch operators–Nederlandse Spoorwegen (NS), Prorail, and Strukton–are conducting a trial with two local universities. A train is equipped with a laser and a device to measure braking ability.
“The question is not so much whether the laser system works, but for how long the rails will remain clean,” says Rolf Dollevoet, a professor at the Delft University of Technology. “We’ll measure the remaining friction over time during rain, drizzle, frost and snowfall. From these measurements NS and Prorail can derive at what frequency the 6,000 kilometers of track need to be lasered and how many trains have to be equipped with lasers to achieve that.”
It’s not the first time lasers have been considered for the purpose. Back in the 1990s, a British entrepreneur successfully tested a train laser with the Fraunhofer institute, in Munich, and Rofin-Sinar, a company in Hamburg. It produced 25,000 pulses per second and worked at speeds up to 40 miles per hour. No operator took the idea on, however.