Carriage Wash
Mechan is expanding its depot maintenance product range with the addition of commercial carriage washing machines for tram, metro, light and mainline rail applications.
The run-through train washing system sits in the middle of tracks and is designed specifically to keep the exterior of rolling stock in the highest state of cleanliness.
The machine cleans the lateral sides of the car, with an option to include the front and back, in a four-stage process:
// pre-wetting
// scrubbing and brushing
// rinsing
// drying
In its normal mode, the train washing machine operates automatically. Start-up is controlled by the arrival of a train and various sequences take place depending on the type of car, which is determined by photocell and/or a proximity detector. In manual mode, these sequences are controlled by pushbuttons.
Vehicles of between 12.5 metres and 32 metres in length, 2.2 metres and 2.65 metres wide and 3.0 metres and 4.8 metres in height can be accommodated. They are run through the machine at 5kph, whilst cleaning is in process, although this speed can be increased to 10kph when the machine is not in use.
Brushes
Two sets of vertical brushes clean the lateral faces of the train. The bristles ensure proper friction, whilst remaining flexible and strong enough not to be torn out or cause damage to exterior fittings that protrude from the car.
To limit water splashes, brushes are fitted with sturdy wraparound protective screens. They are mounted in two positions - operating and idle - and will always return to the idle position when the machine is stopped.
Spray nozzles
Spray nozzles are fitted to the ramps and tubes at each spraying station. The end of the nozzle distributes water at a 60 degree angle in a thin spray, to ensure optimal efficiency. They are positioned to cover all directions once the machine is installed and whilst their flow rate is not excessive, it is adjustable to prevent dispersion of mist.
Control desk
The control desk should be situated in a room close to the wash area or depot. It comprises a series of pushbuttons and illuminated switches, grouped by function, to control the various parts of the washing machine.
Traffic lights
The front and rear of the train are positioned for the washing process via a 'traffic light' system. The first is located at the module bridge and is activated by a proximity sensor. The car has to stop when the light is red, at which point the brushes begin to revolve. At the end of the cycle, the green light is illuminated and the train can advance. A second red light indicates when to stop for the rear washing to begin.
The treatment process
Vehicles are washed with recycled water that has been stripped of all polluting products and substances, such as oils, grease and other hydrocarbons, immiscible solvents, suspended solids, organic matter, most heavy base metals and precipitable inorganic salts.
The treatment process begins with the collection of the wash-waters and their transfer to the pre-treatment tank. From there, the waste is automatically pumped to the main treatment unit where solids are extracted. The remaining water is passed through a filter before being stored in the 'treated water' tank for reuse.
Although the treated water is clean and suitable for recycling, storage for long periods may give rise to disagreeable odours, most common in high summer temperatures. At the client's request, the plant can be equipped with a chlorine dosing system to prevent smells occurring.
