AN array of 24 satellites may help to weave a tighter safety net for America's passenger and freight trains.
Later this year, two of the nation's largest railroads are joining forces to see if navigation satellites initially designed for military use can monitor and, if necessary, control trains on 800 miles of track in the Pacific Northwest.
If the series of experiments is successful, advocates say, the technology could usher in an era of safer train travel for at least 21 million passengers each year. It also could allow the rail network to handle more traffic and help lay the foundation for future high-speed passenger links along the country's more-populous corridors, such as Chicago-St. Louis or Seattle-Portland, Ore., routes.
Even now, rail remains one of the safest means of transportation, insist federal and industry officials. Yet since the first of the year, 19 train wrecks have killed 22 people and injured some 230 others. The two worst mishaps, involving commuter and passenger trains in the Northeast, killed 14 and injured 188.
Testifying last week before a House subcommittee, National Transportation Safety Board (NTSB) chairman James Hall said that many rail accidents could have been avoided if existing and new technologies had been in place. These systems maintain and enforce adequate separation between trains.
Railroad officials note that railways have become more crowded over the past decade. "As railroad traffic increases, the risk of major accidents involving passenger trains and freight trains also increases," Mr. Hall said.
The first system to automatically stop a train if an engineer failed to heed a signal was tested in 1919. But as passenger traffic declined in subsequent years, railroads decided the equipment was too expensive to maintain on a network largely carrying freight. The only segment of track with a permanent automatic train-control system is the Northeast corridor, a heavily traveled section between Washington and Boston.
The NTSB began to advocate the widespread adoption of train-separation technology more than 20 years ago and has repeatedly renewed its plea following subsequent accident investigations. Yet the industry has balked at the cost, inflexibility, and complexity of existing approaches. And federal regulators have been content to leave decisions about adopting the technologies to industry.
Burlington Northern experimented with controls using global-positioning-satellite (GPS) data in the late 1980s and early '90s, says Dick Russack, a spokesman for the railroad. "It gave us some insights into a variety of factors and system requirements. But it was an exceedingly expensive proposition to go after," he says.
The industry estimates that installing a nationwide GPS train-separation system could cost it up to $1.1 billion. Even NTSB officials acknowledge that the cost could be seen as prohibitive, given the incremental increase in passenger and crew safety.
But the economic equation may be changing, according to an official with the Federal Railroad Administration, which regulates railroads. "The cost of the electronics is dropping, and the railroads are experiencing traffic growth," he says. This is placing greater demands on railroads to make more efficient use of existing track and trains.
Burlington Northern Santa Fe, along with the Union Pacific Railroad, are splitting the $35-million cost on this year's test in the Pacific Northwest. The trial involves placing GPS receivers and computers in locomotive cabs to pinpoint a train's location to within a few yards. The on-board computers, as well as those at dispatch centers, hold the "rules" for speeds and train-to-train distances along each segment, or block, of track. If a train exceeds the speed limit for a given block or moves too close to another train, and if the engineer fails to act, the automated braking system would kick in.