The long-term future of electrification in the UK rail industry has been regularly discussed particularly when severe winter weather can highlight its inherent weakness when covered in snow and ice. The situation has become more severe with the use of lighter current collector shoes on electric train sets which, unlike the heavier designs used in the past, are less able to scrape off even quite thin layers of ice or snow. The newer designs of trains are less happy to run when the current supply is arcing and fluctuating through poor contact between shoe and electric rail – this exacerbates the situation.
Grinsty Rail has developed solutions to combat this problem. The company has designed on-train systems which are able to remove ice from the top of the third rail. A Grinsty Rail system activates a spray mechanism which dispenses de-icing fluid onto the rail surface, creating a good contact surface for the collector shoes, or alternatively dispenses de-icing fluid through special collector shoes.
The systems, which can be configured for third- and fourth-rail supplies, can be fitted to electric trains themselves, removing the need for special de-icing units. There are several key components including a fluid storage tank, control unit, pump unit, fluid dispensing nozzles and track detectors. The under-body mounted tank, which is designed and supplied by Grinsty Rail, is made from stainless steel to provide excellent durability and long-term corrosion protection and allows the vehicle to carry a large volume of de-icing fluid.
Clearly, where the mechanism is employed it is important to ensure that the fluid is only applied to the correct side of the rail vehicle. Thus, the position of the live positive rail is continually sensed using a laser detection system and a manifold diverts the fluid accordingly. The control unit responds to a speed input signal and drives the variable speed pump to dispense de-icing fluid according to the vehicle speed, with the system ensuring that the two fluid dispensing spray nozzles apply the de-icing mixture directly onto the active current rail through electrically insulated hoses at the recommended rate of 1.2 millilitres per metre. A long-life strainer on the tank outlet prevents pump contamination. If a low-level signal is detected the pump is shut down automatically.
Initially the systems were developed to use a de-icing mixture of ethylene glycol and water, however recent enhancements now allow the use of ‘greener’ proprietary branded anti-icing fluids which provide a greater adherence to the conductor rails and thus provides a long-lasting anti-icing film to the top of the conductor rails. All the system components can be specified to meet specific vehicle requirements and have been designed to provide prolonged and trouble-free service with minimum maintenance.
With depot time always at a premium, especially in times of severe weather, a fast refill of the onboard tanks is achieved by high capacity automatic shut-off filling valves located on each side of the tank alongside clearly visible contents gauges. A tank sender unit reports tank fluid level to the vehicle control system via the De-icing Control Unit.
The Grinsty Rail system has seen considerable interest from vehicle manufacturers and train operators. The system is fitted to Northern & Jubilee Line, SSL, South Eastern & East London Lines and TfL Class 710 vehicles.
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