Metro slowed its trains on all its above-ground tracks starting at 2:30 p.m. Tuesday due to the heat, less than two hours after announcing a new set of guidelines for how to run trains during hot spells in the wake of a recent derailment.
Separately, the agency said it would allow riders to drink water in the system on Wednesday, the fourth time this summer, as temperatures are expected to top 100 again. Normally, drinking is forbidden, but Metro rarely enforces it, issuing no citations for drinking anything but alcohol in June. Still, water was not allowed on Tuesday when the high temperature reached 100.
Under the new heat guidelines, Metro will slow trains to 35 mph on above-ground sections of the 106-mile system if the temperature of the metal rail reaches 135 degrees or more -- or if the region has a prolonged hot spell without sufficient cooling at night. The system's normal maximum speeds are 59 mph.
Such slowdowns delay trains systemwide, especially during peak periods when trains are scheduled as close as three minutes apart.
"While these speed restrictions may cause some delays and inconvenience, they are intended to put the safety of our passengers first," Deputy General Manager for Operations Dave Kubicek said.
Metro enacted the guidelines after a July 6 Green Line train derailment that has been blamed on a "heat kink" deformation of the track due to the hot weather. No one was hurt, but crews spent the weekend repairing more than 1,000 feet of damaged rail.
Heat restrictions are common on railways. They do not prevent kinks from occurring, but they lessen the risk of a serious accident if one occurs. The rules vary widely among railroads, though.
Metro has used such slowdowns in the past, including in July 2010. On the day of the recent Metro derailment, though, MARC and Virginia Railway Express commuter trains had restrictions in place, but Metro waited until after the derailment.