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After a disastrous 2006 slippery rail season that left hundreds of cars, including brand-new M-7s, crippled by flat wheels, Metro-North began an intense, multi-departmental effort to tackle the problem. The result was the best-ever November on-time performance in Metro-North's 25-year history, 98.1 percent.
This aggressive program of high- and low-tech solutions combined to combat the gelatinous residue that results when wet leaves are crushed under train wheels causing "low adhesion." Slippery rails cause train wheels to skid along the running rail resulting in flat spots that require a train to be taken out of service so that the wheels can be made round again, or "trued."
The multifaceted program resulted in fewer delayed trains and a big reduction in wheel defects. Comparing the period Oct. 15 through Dec. 9, 2006 with the same period this past fall, total delay minutes due to low adhesion was 4,467 in 2006 but just 1,425 in 2007, a 68 percent reduction.
Also, on the worst day in 2006, there were 255 electric train cars out of service for wheel defects, compared to just 32 on the worst day of 2007, an 88 percent reduction.
The most important correction involved programming changes to on-board computers on the M-7 electric cars in use on the Hudson and Harlem lines. Sensors feeding data to the complex, computer-controlled propulsion and braking systems had interpreted skidding as a train exceeding the allowable speed and resulted in an emergency brake application. When the brake is applied automatically, an engineer cannot override it, resulting in the train grinding to a complete stop and many flat wheels.
The programming change, managed for the railroad by Timothy McCarthy, director of equipment - capital engineering, still will not allow an engineer to override an automatic brake application — that's an important safety feature — but based on the longer distances the signal system uses to ensure the safe separation of trains, on-board computers have been reprogrammed to safely stop the train by gradually applying the brakes with antilock protection so as not to trigger an emergency stop.
A related, human-based response was championed by Dave Schanoes, the railroad's deputy chief of field operations. As a member of the Low Adhesion Working Group, a committee of some of the railroad's best minds created to address the slip-slide issue, Schanoes suggested that when leaves and water reduce the friction between the wheel and the rail, less severe braking is more effective braking.
So at the first sign of slip-slide, Metro-North implemented slow speed orders — it worked. Slow speed orders didn't hurt on-time performance because only certain stretches of track are susceptible to slippery rail so only a portion of each trip would be at slower-than-maximum speeds.
Railroad employees also increased use of "Waterworld," a Metro-North-designed and built machine that uses 10,000 pounds per square inch of water pressure to blast leaf slime off the rails. These two, diesel-hauled machines ran virtually all night every night during the 2007 leaf season.
Our investigation of the slippery rail phenomenon extended into the laboratory. Samples of the slime were scraped off the rails by Karen Timko, director of environmental compliance, and sent for chemical analysis. Turns out the goo was slightly acidic, so an alkaline solution was added to Waterworld tanks and proved more effective than water alone.
Another piece of machinery developed by employees here is a rail scrubber, a pair of rotating steel brushes, powered by suped-up lawn mower engines, mounted on the back bumpers of "high-rail vehicles" and lowered onto the running rails. These modified pickup trucks can be dispatched via highway to the trouble spot at the first sign of slip-slide. They provided daytime backup to Waterworld, which has a maximum speed of just 30 mph and is only used overnight so as not to interfere with train traffic.
Finally, the railroad updated instructions for train engineers regarding operating during low-adhesion conditions. In addition, low-adhesion areas were identified by the new M-7 software and reported automatically via a wireless data connection to the Operations Control Center (OCC). The OCC then notified engineers via radio about when and where to expect slippery rail.
It was a team effort that paid off for our customers.
John Kesich is the assistant chief mechanical officer at the MTA Metro-North Railroad.
author: John Kesich