In cold and snowy weather, such as the recent snowstorm and ensuing frigid temperatures across the Chicago area, railroad agencies sometimes employ flames to allow trains to smoothly switch tracks.
Snow and ice can lock up switch points — the movable rails that allow the train’s wheels to connect to another line. Trains enter a “fail safe” mode when switches are frozen or clogged and unable to connect to another rail, causing the train to stop until the blockage is cleared, Metra said.
Amtrak, Metra and other rail operators often use heat in a variety of ways, including natural gas-powered flames, to combat the issue in colder weather. The flames, fed from a gas system adjoining the rail, make the tracks look like they’re on fire. They’re most often used in areas dense with switches.
Gas flames have been used on rail switches across the Chicago area this week, which has experienced an extreme cold stretch not seen since 1996 with temperatures failing to reach 5 degrees for three consecutive days.
Other forms of switch heaters include tubes that use electricity to generate heat and hot air blowers, the most common method, that use both electricity and natural gas.
Flames also can cause heat damage to rail ties, leading to a few being replaced each year, but the method is still safe and effective because operators have “far more control over the flames,” Metra said.
“It’s important to note that diesel fuel combusts only with pressure and heat, not open flames. Therefore, operating our locomotives and railcars over the switch heaters is completely safe,” Metra said in a statement.
Train agencies could possibly be able to cut back on using switch heaters soon, as temperatures are expected to climb into the upper 30s early next week.
