Light rail -- frozen in its tracks

January 29, 1994|By Peter Jensen | Peter Jensen,Staff Writer

Like Achilles discovering his heel, Baltimore's $364.4 million light rail system has inadvertently revealed a vulnerability: low temperatures and freezing rain.

With the possibility of snow returning to the forecast, Mass Transit Administration (MTA) officials have been scrambling for remedies. They don't want a repeat of light rail's performance beginning nearly two weeks ago when trains were literally stuck in their tracks.

"It was a surprise that we could be impacted to that extent," said John A. Agro Jr., MTA's administrator. "It's been a learning experience."

The trouble began the evening of Monday, Jan. 17, when icy weather shut down the Central Light Rail Line for six hours, stranding 42 passengers on a train near Camden Yards until early morning hours. The system went back into service Tuesday -- until the other meteorological shoe dropped.

As temperatures plunged to 5 below zero that evening, so did the quality of service. Trains had to be replaced by buses over portions of the 22.5-mile system for the rest of the week. Full service was restored Tuesday.

Ice covering the rails, the catenary (overhead electrical lines) as well as the pantograph (extendible devices that collect electricity from the overhead) caused much of the problem. Without proper electrical connections to wires and rails, light rail cars are powerless.

The arctic temperatures were blamed for causing a mile-long section of catenary over the Middle Branch of the Patapsco River to collapse Wednesday morning. The problem took several days to repair.

"We don't know for sure what happened, but we think it was related to the temperatures," said MTA Deputy Administrator James F. Buckley.

MTA officials concede that the 2-year-old light rail system was at its most unreliable last week, and that may strike many people as puzzling. Trains should be more resistant to weather than automobiles. Light rail cars experienced no problems during the blizzard in March.

But the reality is that railroads and streetcars have never been immune from the effects of winter weather, especially ice. It's particularly a problem for systems that rely on overhead electric lines.

"It's something the transit industry has always had trouble with," said Frank J. Cihak, chief engineer for the American Public Transit Association. "There are not many new techniques to combat this stuff."

In Pittsburgh, light rail trains were delayed up to 30 minutes last week and buses replaced trains on one stretch of track for two hours Wednesday. The city got socked with up to 3 feet of snow and temperatures that fell to minus 22.

Spencer J. McKain, manager of rail operations for the Port Authority of Allegheny County, said the lines contracted and twisted in the cold weather. The light rail cars couldn't make proper contact. "The weather was so extreme, you just can't allow for that," he said. "We didn't get the freezing rain. Most of our problems were with the high snow."

While Portland, Ore., didn't have to endure last week's severe cold, the city's light rail system has occasionally been shut down by ice, a spokesman said.

"Ice is a nightmare," said Richard E. Rogers, manager of rail equipment maintenance for the Tri-County Metropolitan Transportation District of Oregon. "It's our worst situation. We say our prayers when it's in the forecast."

Mr. Rogers said Portland's Metropolitan Area Express or "MAX" recently installed equipment to address the problem, but he doubts it's a cure. "When we've had a severe freeze, we've had wires down, too," he said. "It's a tough thing to design into your system."

Baltimore's subway system experienced only minor delays in the harsh weather. Metro trains are powered by a third rail that is heated and covered, protecting it from snow and ice.

To prevent the system from failing again, MTA officials are looking into several ice-fighting techniques. Perhaps the most significant is a heated pantograph developed for Boston's "T."

The device features serrated brass strips with grooves 1/8th of an inch wide and 3/16ths of an inch deep, replacing normal carbon filaments. The pantograph, called an "ice cutter," is designed to scrape away ice from overhead lines without inflicting much damage to the soft copper wires.

The MTA had an ice cutter flown in this week from St. Louis and plans to test it during any snow storms next week, Mr. Buckley said.

Transit officials already run trains around the clock when severe weather is forecast to break up snow and ice on tracks and wires. In the future, officials are considering using de-icing fluids as well as a special grease smeared on the pantograph to protect it from the elements.

The MTA plans to wire together cars on a train so they can share a power source. If one or two cars fail to make a proper connection to the catenary, a single pantograph can provide power.

A diesel locomotive has been transferred from use on Metro to the light rail so that when a light rail train stalls again, it won't take 6 1/2 hours to free it.

There are no guarantees that ice won't wreak havoc in the future. The best consolation for travelers may be that recent weather conditions were downright freakish. MTA maintenance crews have never seen ice form so quickly or thickly, or temperatures plunge so low.

"We had aerials on supervisors' cars bending over from the ice," Mr. Buckley said. "I've never heard of that before. This was an unusual situation."

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