For the safety and comfort of passengers, the importance of track maintenance cannot be overstated. A well-maintained track results in a smoother ride, reduced wear and tear on trains, faster speeds and prevents derailments. Track degradation is caused by the day-to-day travel of trains, which can cause track instability, and can vary depending on weight placed on a track, speed, climate and various other factors.

Regular track inspection is essential in ensuring a safe track. Specialized machines are now used to do a significant amount of maintenance work, which ranges from rail testing for flaws to rebuilding damaged, worn or derailed tracks. Choosing whether to buy a track maintenance machine or to contract out a company for maintenance purposes depends on the individual needs of transit agencies.

Plasser American Corp.

Based in Chesapeake, Va., Plasser American Corp. designs and manufactures rail maintenance equipment for sale to clients.

Over time, as trains continually travel over tracks, the ballast, or rocks underneath the track become unevenly settled, resulting in what would be equivalent to potholes on street surfaces. A tamping machine fixes this problem by lifting the track and packing the ballast underneath the ties to level out the uneven surface that the track lays on.

Plasser's Metro 4x4 is one of the company's smaller tamping machines. Designed for transit agencies, the Metro 4x4 can be built in different configurations and is used by Boston's Massachusetts Bay Transportation Authority, Metropolitan Transportation Authority's New York City Transit and Long Island RailRoad, Dallas Area Rapid Transit, Maryland Transit Administration, Toronto Transit Commission and the Port Authority Trans-Hudson. The Metro 4x4 comes standard-equipped with fully automatic, computer-controlled Automatic Geometry Guidance System (AGGS) lifting, leveling and lining systems.

During the tamping process, the ballast bed is disturbed. A dynamic track stabilizer is often used behind the tamping machine. The PTS 62 Dynamic Track Stabilizer is the largest that Plasser manufactures. Using hydraulic cylinders and vibration to force down the track, the rocks shake themselves into a compact state. The vibration and controlled vertical load create a more stable position for train traffic. The Dynamic Track Stabilizer settles the disturbed track bed in a controlled environment, thus reducing the need for slow orders and allowing trains to run across maintained track at scheduled speeds.

The PBR 550 ballast regulator brings ballast that has flowed out from the track section back into it. This improves the appearance of the track and keeps the track in place. The outward flow of ballast is caused by trains over the track, but weather conditions and temperature can affect ballast movement as well. Regulating typically comes after tamping, or, if a stabilizer is used, the process comes after stabilizing. 

Track recording cars ride along the track and take geometry measurements of its cross-level, surface or alignment. The latest of its kind is the TGC 04, which is specially designed for a transit railway, and can be fitted with a multitude of measuring and recording functions that include a GPS locator; rail flaw detection system to locate defects inside the rail; and a clearance measuring system that measures the track in relationship to platform edges, tunnel walls, etc.

The type of track recording car used depends on what the customer is looking to measure, and each machine can be fitted with the function needed. NYC Transit recently purchased one of the most multi-functioned vehicles that Plasser American makes.

Equipment size can vary and reach lengths of several hundred feet, but the equipment mentioned above can stretch to more than 56 feet in length. Machines are always stored on side tracks, maintenance yards or buildings and their maintenance depends on usage. Regular oil checks and air filter changes are necessary, as are monthly and annual checks.

According to Plasser, the cycles for track maintenance vary greatly based on climate, tonnage, speed and track usage, and can range from three times a year to once every several years, depending on each railroad's maintenance guidelines.

Herzog Companies

For transit agencies not ready to buy maintenance vehicles, Herzog Companies leases out machines for rail maintenance and construction projects and provides a trained operator for each machine. The St. Joseph, Mo.-based company specializes in rail equipment, railcar leasing and rail testing services.

Operators are "trained in efficient operation of the unit...and railroad safety training," says Joe Kneib, senior vice president, market development. Leases range from short-term to long-term and include equipment maintenance as well.

Herzog manufactures and leases the Ultrasonic Rail Flaw Detection machine. Its Series 6000 is designed to operate without stopping and can test rails at a maximum of 20 mph. Machine operators "shoot ultrasonic waves at the rail at different angles and look for cracks, scaling and defects on the rail," says Kneib. The location is marked physically, and the machine makes a note of it on the computer.

Kneib says testing ranges from once a quarter to once a year, depending on the frequency of track use. The lease cycle is usually multi-year, and cost depends on how often the service would be used, based on a daily rate.

The Multi Purpose Machine (MPM) is designed for all types of rail systems. Comprised of a diesel electric power unit and six rail cars, it can run by remote control, allowing the operator to multi-task. Operated by one person, its rotating arm has a 27-foot reach for cleanup, removal or redistribution of other track material such as bolts, spikes, plates and clips, re-ballasting, ditching or grading. It also can be used for picking up, stacking or distributing ties, tie butts and rail.

In January, when the derailment of a freight train in Littleton, Colo., led to the interruption of Denver Regional Transportation District light rail service, Herzog's MPMs were able to quickly rebuild the area. Two MPMs, capable of traveling 50 mph, arrived from Wyoming hours later and worked for 11 straight days. The MPMs helped with cleanup, demolition and transport of material to make the repairs.

According to a Herzog report, without the MPMs, "these repairs would not only have taken longer, but would have involved the dismantling of the overhead catenary electrification system and demolition of the adjacent LRT track, possible damage to the station platform and blockage of the main line." Kneib adds that with the MPMs working around the clock, repair costs were 25 percent to 30 percent lower than original estimates.

Harsco Rail

Harsco Rail, formerly Harsco Track Technologies, designs and manufactures an extensive line of track maintenance equipment. In addition to equipment sales, the Columbia, S.C.-based company offers service contracts for rail grinding, track renewal, track undercutting and tie pad change-out systems.

For damaged or worn tracks that need replacement, Harsco's Track Renewal Train (TRT) can be used to change ties and rails in one pass. "Most railway systems don't build or renew enough track to justify owning one of our machines, so we provide contract services," says Chris Larsen, director, business development, who recommends the TRT for larger projects that require all ties and rail to be changed out.

The TRT can renew more than a mile of track a day and works on both wood and concrete ties. Through one pass, its functions consist of removing old ties and old rail, preparing the track bed for new ties, laying down new ties, putting the new rails in place and applying fasteners. Specially-designed cars behind the machine are used for transport of new and old ties to and from the worksite.

"It's a safer, faster way to accomplish large track renewal programs," says Larsen. "If you have a program where you need to change out all your ties and rails at the same time, then this machine can do it at a very reasonable cost and much quicker than alternative methods."

Another machine offered by Harsco is the Production Transit Grinder, which is used to remove irregularities from worn rail and restore its head profile. Diesel-powered, the grinder has climate-controlled control cabs on each end for bi-directional grinding and driving and travel speeds of up to 50 mph.

It contains rail measurement equipment that measures and records the profile and corrugations of the rail head in order to better select grinding patterns, and a dust collector system which traps grinding residue, thereby keeping the work area cleaner. The grinding computer system uses graphics-based control screens for easy operation. Automatic obstruction avoidance can be programmed for each rail, and a fire control system is included to extinguish ground fires that may occur.

Grinding is also available as a service contract. "Implementing a scheduled grinding program will help a railway to improve ride quality, reduce noise and reduce rail and wheel wear," says Larsen.

Harsco Rail works with various railroads, transit and commuter rail systems throughout the world, providing complete maintenance solutions through innovative technology and hands-on experience.

RailWorks Corp.

RailWorks Corp., based in New York, specializes in construction and maintenance services for track and transit systems. With decades of experience serving busy transit operations, the company offers a range of customized track and signal inspection and maintenance services.

RailWorks will gear its inspection regime and frequency to the geography and operating requirements of each specific transit system. Inspection frequency will vary but can be daily, depending on the type of track, FRA/Transport Canada requirements and other agency requirements. 

"Our prime responsibility is to ensure that the track and signal infrastructure remain within customer's standards," says Dave Wilfong, vice president of operations, Eastern Canada, PNR RailWorks Inc., the Canadian subsidiary of RailWorks Corp.

A thorough track inspection involves walking the track and evaluating the sub-grade, rail, ties, ballast, switches and turnouts. A senior member of the inspection team will also regularly ride the rails to see if conditions have changed and to evaluate the smoothness or irregularity of a ride. If the inspector notices a variance, it is noted for further measurement and testing.

On any given day, PNR RailWorks and its RailWorks counterparts in the U.S. regularly maintain thousands of miles of track and turnouts and hundreds of signals. PNR RailWorks has performed track inspection services for GO Transit in Ontario since 2001. In the U.S., RailWorks recently won contracts to construct and maintain the SunRail commuter rail line in central Florida and to maintain 196 miles of track and signals owned and operated by the New Mexico Department of Transportation.

In addition to regular track inspections, supplemental services can include vegetation control, brush cutting, track geometry measurements and ultrasonic rail inspections to identify internal flaws in rail and emergency response services.

 RailWorks also specializes in signal inspection work. According to Wilfong, some signals may require weekly inspections to monitor batteries and electronics. "These inspections are rather technical and require technicians with background in specific electrical components," says Wilfong "These inspectors generally have responsibility for the signals within a designated territory."

Scheduled track and signal inspection programs assist agencies in planning maintenance and larger construction projects. "Not everything needs to be attended to immediately, so RailWorks recommends a cost-efficient program that will save agencies money in the long run," says Wilfong. "With this type of program we'll spend a week or two on the track to address priority concerns." For projects that need larger amounts of funding and advance planning, "we provide agencies with a comprehensive list to help them develop a capital budget," says Wilfong.