March 2002

Digital Railroad

Continued from page 3

By Don Phillips

Trains must run on tracks, of course. And once laid, the rail and ties must be maintained and inspected. Information technology is playing a transforming role in this traditionally labor-intensive affair. The last two or three years, for instance, have seen the advent of rail alignment systems that use lasers to gauge distance and direction. Computers then figure a track's correct curvature and angle of elevation and feed the information to machines that put the rail and ties into place. "The important thing is the ability to measure track geometry rapidly, without depending on human sight," says Louis Cerny, an independent railroad consultant in Gaithersburg, MD.

One particularly time-consuming rail maintenance job-spreading rock ballast between tracks-is also getting a shot of adrenaline. In June, Herzog Contracting-a railroad construction company based in St. Joseph, MO-delivered a new ballast train to Union Pacific. Unloading 60 cars of ballast normally takes at least two days; Herzog's train does the job in 30 minutes. As the train chugs along, computers guided by global positioning system satellites decide which car doors to open and how much ballast to pump out (even interrupting the flow at road crossings).

Similar advances are aiding track inspection. This job was once the domain of a lone trackwalker, carrying a few heavy tools, who walked along the track to see if it was shifting, or if spikes were pulling out or rail joints flexing too much. The ultimate in automated track inspection is a system delivered in 1999 to the Federal Railroad Administration by Plasser American, a maker of inspection cars, and Ensco, a manufacturer of railroad inspection hardware and software. This self-propelled mass of sensors and computers, rolling along at up to 145 kilometers per hour, generates readouts of track condition and dispatches crews to the locations of any problems. Most of the major freight railroads in the United States are either using such cars now or have ordered them.

Ensco has also developed remote monitoring systems that can be fitted to any railcar or locomotive. The systems, now in service for Amtrak and several commuter railroads, continually assess track anomalies, ride quality and a locomotive's mechanical health. When a problem appears, the monitors send an alarm via satellite or terrestrial wireless link. Detailed information on the problem and its exact location can then be accessed through the Internet. Other new inspection equipment uses computerized vision to look for defects in air brake hoses between cars. Pulsing lasers, fanning out in a pie-slice shape, can accurately produce an image of the wheel as it rolls-registering surface defects better than an experienced inspector can when the wheel is standing still. All of these detectors are designed to report trouble spots to the train crew or the dispatcher before a small problem grows and causes a wreck.

Down the Line

With the cost of technology constantly falling, railroads may be poised for another round of automation. The first candidate is an idea railroads have so far shunned called positive train control. The computers that control a locomotive's throttle and brake would be equipped with global positioning system receivers that tell them precisely where they are and how fast they're going. The modification was originally proposed as a safety enhancement, to prevent collisions: if an engineer sped past a stop signal, the system would signal the computer to slow or stop the train. That application failed to win over the railroads, though. "It would have cost a lot of money for a minimal safety improvement and so wasn't cost effective," explains MIT's Martland.

But many railroad officials are beginning to understand the business case for positive train control: the same technology provides continual updates on the location of every locomotive on the railroad. Advanced tracking and control technology is already in place on high-speed passenger trains such as those on the Boston to Washington line. The technology is also under development at a number of companies, most prominently Pittsburgh-based Union Switch and Signal.

Combining satellites with computers to govern a train's speed is only one step toward completely computer-automated operation. Subways routinely operate this way; the driver goes along for the ride. But a freight train is not as simple as a subway. A long train may be climbing one grade and descending another at the same time, for example. And every freight train has its own braking characteristics, which an engineer must quickly master; mishandling a train can cause serious damage, like torn couplers and perhaps even derailments. Some railroads, however, are experimenting with computers that can learn a train's characteristics as fast as an engineer can. For example, computers have taken control of heavy ore trains in Minnesota, operating efficiently and stopping smoothly at red signals.

The next logical step is fully automatic operation, with an engineer on board only as a monitor. While the technology to implement this largely exists, other factors stand as barriers. The hefty up-front costs, for example, discourage railroads from installing new systems that don't provide an obvious bottom-line benefit. Safety is another concern; automated control systems must be proved extremely reliable before they can be trusted to replace human operators, and it is not until such a substitution is possible that the technology has much of an economic payback.

Computerization has already made it possible for railroads to operate with fewer people. The newest developments represent an assault on the jobs of the two most important people who run a train: the engineer and the conductor. And deployment requires renegotiating contracts with labor unions representing workers whom new systems might displace.

It is looking as if the long climb up the Toponas grade is just the beginning of an accelerating journey into a computer-automated future. Says Union Pacific's Iden, "We're just starting to tap into the benefits of technology."