(The following article by Ray Reed was posted on the Roanoke Times website on May 19.)
ROANOKE, Va. — In a Pullman car built in 1923 but outfitted now with video and laser beams, Norfolk Southern Railway engineering technicians peer at emerging defects in rails.
Their challenge is to predict when a rail at a certain milepost in the 22-state system will wear thin or get loose enough to cause a derailment.
The company wants to plan its maintenance so the rail can be fixed just in time to avoid an accident, said Robert Blank, director of research and testing for NS in Roanoke.
The goal is to make repairs on a schedule that doesn’t interfere with shipping times. That keeps shippers happy, Blank said.
Technology-based maintenance helps NS avoid horror stories in which a carload of paper towels or food products was stuck on a siding for 30 days while repairs were being made.
Lasers and other sensing devices are the railroad’s best ticket to faster deliveries, as shippers return to the rails they once discarded in favor of trucks.
The evolution under way in maintenance is a necessity as railroads cope with a booming market that analysts think will continue for at least two years.
But those railroads are challenged to carry increasing shipments over tracks that have changed little in three decades.
NS’ research car is perhaps the most advanced maintenance tool in the nation’s rail fleet, Blank said, because other railroads don’t have one like it.
The research car had a week out of service in Roanoke recently so it its cutting-edge technology could be sharpened with a GPS system.
That means the worn spots it finds in tracks now can be recorded by latitude and longitude — a system more precise than reporting that a defect is within 100 yards of a given milepost, for example.
This is the same railroad whose Norfolk & Western predecessor in the late 1950s and early 1960s deferred maintenance during a series of mergers with other railroads.
That system of deferred maintenance was followed in the 1970s by programmed maintenance, which replaced equipment on a schedule designed to anticipate its wear rate.
With technology, NS detects wear-out rates more precisely.
When track in a curve wears faster than expected, engineers start searching out its cause.
On the flip side, some equipment may last longer than expected, and the cost of replacing it can be delayed, Blank said.
NS and other railroads tore up track in the 1970s when shipping volumes declined, and many rail executives today wish they still had some of those tracks.
The best available solution lies in keeping an electronic eye on wear and tear, Blank said.
Other surveillance is conducted by devices called wayside detectors, which listen and feel for defective wheels, bearings and other moving parts in passing freight cars.
The condition of 865,000 wheels per week, on more than 1,500 trains, is being recorded in a database that keeps a log of individual cars, said Scott Keegan, manager of project engineering for NS.
Having the data means that before a flat spot on a steel wheel gets big enough to cause bad vibrations, that wheel gets replaced.
Although the detectors amass a huge amount of data, it applies to only half the cars in a typical train; the other half belong to different railroads or private shippers.
Still, the detectors can help prevent accidents, even with other owners’ cars, Blank said.
Strain gauges also measure track wear, but in a different way. Resembling a tiny plastic strip with wires, strain gauges are attached to rails in a curve to detect whether a train’s weight is distributed equally on each rail.
Unequal weight means the train isn’t moving at the right speed, or a rail has gotten too high or low, said Kevin Conn, also a research engineer for NS.
“For years the railroad tried to make things stronger. Now that process has become more expensive, and we are finding it is more economical to reduce the force we are applying” to rails and wheels, Conn said.
When he measures the force a train applies to wheels and rails, Conn sees three kinds of stress: longitudinal or pulling; vertical or weight; and lateral or side-to-side.
“We’re concerned mostly with controlling the vertical and lateral forces,” Conn said.
Those forces can defy logic.
“Sometimes you can see a wheel rise up off the track,” Blank said, chuckling. When that happens, there’s no doubt about where to deploy the maintenance crew.
What may be less apparent is the defect that caused the wheel to lift.
Those three forces can play out in multiple ways on the track.
The converted research car’s cameras and laser beams record six kinds of defects that occur in track: curve alignment; rails out of level; rails spread too far apart; the cant or angle at which they sit; their surface smoothness; and their twist, or flex.
That information prints out on a chart with squiggly lines that record the ways the rails have, in essence, groaned under the train’s weight.
Technology is much less romantic than the days when veteran railroaders with flashlights eyeballed the wheels and rails to spot defects.
Its thoroughness, however, just continues to increase.