(The following story by Stephanie Mlot appeared on the News-Post website on April 2, 2010.)
FREDERICKSBURG, Va. — Warmer weather means spring is in the air, but it also indicates heat restrictions for MARC trains.
Friday’s 33-degree change in temperature led CSX to issue its first heat order of the season as a precaution.
Heat restrictions are implemented whenever the forecast is expected to reach near 90 degrees.
Every morning, the Maryland Transit Administration receives information from CSX on the restrictions.
“These are designed to reduce the impact on the track structure and minimize the possibility of sun kinks,” said MTA spokeswoman Cheron Wicker in an _e-mail.
As heat increases, the rails expand, placing more stress on the pieces holding the tracks in place. If the expansion becomes too strong for the track structure, Wicker said the rails can shift and cause a derailment.
CSX spokesman Bob Sullivan said the kinks give the tracks a curved look from a straight-on viewpoint.
In the event of a restriction, Brunswick MARC trains will operate 20 mph under the normal maximum speed, about 79 mph on the Brunswick line.
“The effect on operations is generally not great,” Sullivan said, “because the trains are making stops along the way, anyway.”
Unlike freight trains, commuter trains don’t travel long distances at high speeds.
Track inspectors check for kinks during the afternoon rush hours.
Restrictions can also be imposed if temperatures have rapidly increased by 30 degrees within the same day.
“Orders tend to be put in place earlier in the year or when you’re going to have consecutive days of very high heat,” Sullivan said.
Wicker said spring is the worst time for heat orders because it is cold at night and warm during the day.