Parker Pneumatic manifolded solenoid valves in stainless-steel enclosures have been specified as part of the control system for the SmartSander rail sanding system, developed by AEA Technology Rail, to provide superior overall levels of safety and performance for the railways. Every autumn, low adhesion between wheel and rail can cause major disruption to railway services. Trains experience difficulty in applying power both to pull away from standstill and to negotiate inclines.
Wheelslide in braking contributes to the alarming numbers of signals passed at danger (SPADs) and platform overrun incidents that occur each year.
On a bad day, the knock-on effect of all these individual low adhesion incidents causes significant disruption to services and adversely affect the safety, performance and hence the credibility of the whole industry.
Many techniques are employed to combat the problem.
However, the autumn operational and safety problems remain a significant factor and service delays continue to increase as greater demands are made on the network.
AEA Technology rail worked with track and train operators to develop SmartSander which, following successful trials, is now used by various major UK train operators.
The key advantages of the SmartSander over traditional automatic sanding systems is the ability to deliver sand in every brake step, the amount of sand delivered being varied according to driver brake demand.
At the heart of the SmartSander system are the three Parker Pneumatic manifolded solenoid valves, which have been packaged in line with the AEA Rail Technology specification and requirements, to provide a complete system solution that will interface with sensors on the train wheels.
These sensors detect the amount of traction loss at the wheel/rail interface and trigger a variable amount of sand to be jetted on to the rails.
The SmartSander has the potential to improve adhesion conditions for all traffic on a given route.
The ability to apply sand in traction and in all braking steps means that a unit equipped with a SmartSander effectively 'treats' each and every low adhesion site that the unit encounters.
Thus, if there are sufficient SmartSander equipped units operating on any given line, any leaf film built up on the railhead in normal daily operation is likely to be broken up through the repeated application of sand until such a point as normal levels of adhesion are obtained.