Interface - The Journal of Wheel/Rail Interaction

FRICTION CONTROL

Controlling Top-of-Rail Friction (continued)

Locomotive-based systems, which are similar to the flange lubrication systems that were introduced some years ago, represent the most appealing method of obtaining system-wide coverage. To do so, however, requires virtually the entire locomotive fleet to be equipped—a process that would take railroads years to accomplish. Beyond installation, reliability and operating issues remain. "You need a buy in from the track people, transportation and operating departments for these systems to work properly," Reiff said. "Thus far, that has been a major stumbling block."

Hi rail-based systems require track time to operate on a regular schedule—a tall order on many railroads. As a result, the durability of friction control products must be improved in order to make hi rail delivery systems viable for mainline use.

Wayside friction modifier systems, which are very similar to traditional wayside lubrication systems, show near-term promise for site-specific solutions. They've been shown to be effective when spaced more than a mile apart. Application rates must be properly adjusted to ensure that the system is economical, he said. "We also need to continue to look at the durability of the components."

Test Sites
The AAR working with the FRA and several Class 1 railroads has conducted several demonstration projects to monitor TOR friction control. The AAR monitored the curving forces of 65-car unit trains on 10-degree curves on Norfolk Southern over a six-month period. "During Winter and Spring months, we saw a 15% to 30% reduction in curving forces on both the high and low rail on trains equipped with top-of-rail systems," Reiff said. Trains that were mixed in, but not equipped with TOR systems, saw some residual benefit, with up to 15% reduction in curving forces. After several months of testing, however, a long-term slow order was put into effect, nullifying the benefits of TOR-equipped trains, since the systems were turned off whenever dynamic or air brakes were applied.

Other issues relating to locomotive-mounted systems in these tests include that in some cases, the units were out of product. "If you don't fill up the reservoir, you're not going to get anything on the rail," Reiff said. Furthermore, he said, train crews didn't know if the system was operating or not. "In order for locomotive based top-of-rail systems to be effective, the system must provide feedback to the train crew and the locomotive service staff must be made part of the program."

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