Interface - The Journal of Wheel/Rail Interaction

SEASONAL LOW-ADHESION

Addressing Seasonal Low-Adhesion Issues (continued)

Innovative Technology
The Adhesion Working Group (AWG), which formed after the privatization of British Rail, has spearheaded and encouraged solutions to these leaf-related problems. SmartSander® a vehicle-mounted, variable-rate sanding system, for example, was developed to increase friction levels on wet-leaf track. This system applies enough sand to improve adhesion without insulating the train from the track circuits. Sanding begins automatically when the driver makes a medium to full brake application. (see Figure 2). When the WSP is operating, limited quantities of sand are used for acceleration, as well. An 80-pound container of the coarse sand (see Figure 3), which is kept beneath the car, generally covers about six weeks of use—even in the autumn period. A sample fleet of 100 EMUs equipped with SmartSander systems showed a 70% reduction in station overruns, a 73% reduction in the low adhesion incident rate and an 80% reduction in wheel truing, which resulted in nearly $1 million per year saving in wheel truing and replacement costs. The system has been fitted to over 700 vehicles in the UK and continental Europe. Most multiple-unit, diesel or electric, trains in the UK are currently fitted with sanding systems to the AWG standards.

When leaf deposits dry they form a very hard insulating film. This Teflon-like substance is a superb insulator and is very difficult to remove. UK railways developed the Track Circuit Assister to deal with this phenomenon. The Track Circuit Assister consists of a transformer that operates at very high frequency (165khz) to induce current through the wheel into the rail and allow the track circuits to operate. The device is fitted to all DMU (Diesel Multiple Unit) trains operating on the UK network.

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