"a component on the fastener that ignited"
Becoming pretty routine....
The rubber casing that provides insulation has apparently broken down on a number of the fasteners, which hold the rail in place in areas where the tracks rest on a concrete base as opposed to wooden rail ties.
Thursday morning’s smoke incident shut down service for more than an hour between Dupont Circle and Gallery Place. It prompted Metro to order a special look at the tracks Thursday night by upper-level engineers, who can help come up with plans for fixes. Power crews were also scheduled to test cables to ensure that they are not contributing to the stray current issues in the area.
When fasteners smolder, it is usually due to the negative return current that runs through the rails reaching the ground.
“It doesn’t always take the intended path,” Lavin explained. “In those cases, stray current is looking for an alternative path. In this incident … there was a component on the fastener that ignited.”
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