NTSB: DC train system had chronic signal problems

WASHINGTON — The signaling system that detects a train on the tracks of Washington’s transit system has been having problems for a year and a half in the area of a crash that killed nine, federal investigators said Thursday.

The National Transportation Safety Board said records show the system on the track circuit had been intermittently malfunctioning, whether a train was present or not, since a piece of equipment was replaced in December 2007.

The equipment, known as an impedance bond, communicates information such as speed and distance between the tracks, trains and operations control center. Investigators said earlier this month that a similar piece of equipment at the other end of the same stretch of track had been replaced five days before the June 22 crash and failed periodically before it.

The NTSB is looking to see whether any reports from the past 18 months or records from train operators might have noted problems with the circuit. “Anomalies” also have been found on other circuits, the board said, and investigators are trying to find out whether the problems are similar to those near the accident site.

Federal investigators said they also are working to determine if other factors could have interfered with the automatic train control system, such as system upgrades and changes.

Metro General Manager John Catoe said initial sample tests of rush hour trains from December 2007 until last month when the other impedance bond was replaced do not indicate the circuit failed to detect trains.

“The circuit appears to have been doing the job of detecting trains,” Catoe said. He likened the intermittent malfunctioning to lights dimming and then brightening again. He said Metro is reviewing all data to ensure the circuit always properly detected trains.

He said Metro checked all of its 3,000 circuits after the accident and found three had problems; two were in a railyard and the other was in use in the system.

Catoe said recent blips that have been found in circuits do not resemble the magnitude of the track circuit problem found near the accident. But he said the agency has stepped up daily maintenance, with two to four circuits possibly being investigated each day. That means passengers could experience delays because trains passing through those areas will have to slow down.

“This is the new norm. And that new norm means a safer system,” Catoe said. Metro planned to set up a Web site Friday showing maintenance locations in its system, he added.

Nine people were killed and more than 70 injured in June when a train slammed into another train stopped on the tracks near the Maryland state line. Since then, Metro has been running all trains in manual mode and has found areas beyond the crash site where signaling equipment has malfunctioned.

Two signal companies that designed and manufactured Metro’s automatic train control system are helping with the investigation, officials said.

Metro is also working with another firm to design a backup for the train control system that is supposed to prevent crashes, the transit agency said. The NTSB had recommended that Metro add real-time, continuous backup to its train protection system.

Federal investigators have not determined what caused the accident, and say testing will continue. So far, tests have shown circuit problems occur more frequently during rush hour.

A sight-distance test on Saturday that tried to determine what train operators would have seen must be further compared with other data from the crash site, officials said. Investigators have said there is evidence the operator of the oncoming train applied the emergency brake before the crash.

Catoe said trains will continue to run manually until investigators determine the cause of the accident and the transit system makes improvements and implements its backup system.

The U.S. House of Representatives on Thursday approved funding for Metro, which would get a $150 million capital infusion to make repairs and replace rail cars. The system has long-overdue maintenance needs.