Switches and crossings are an indispensable part of the railway track. Their functioning must be safe and reliable.
Smooth movement of the switch rails is very important for proper operation. Track narrowing and the risk of flange contact must be prevented to ensure safe train passage. Minimising friction will improve the service life of the switch machines and contribute to track availability.
DeltaSwitch offers a proven solution that eliminates the need for lubricating railway points while improving performance.
Problems with narrow flange clearance or gauge narrowing mainly occur in turnouts with relatively long switch rails. Switch rails resting on rollers in an open position especially can easily be hit and bounce back repeatedly by subsequent wheels. Switch rails that are slightly deformed often do not connect properly to the stock rail.
To promote smooth movement to both end positions, DeltaSwitch’s bi-stable mechanism has been developed and helps the tumbling of the switch rail. A tiltable block midway between the point machine and the heel helps the switch rail to tip over.
DeltaSwitch lifts the switch rail from the sliding chairs, generating enough potential energy to bring the rail into a stable end position, both when opening and closing the switch rail. Because the rail is lifted, friction between sliding chairs and the switch rail disappears and makes lubrication superfluous. This simple solution has been tested and proven to be effective at preventing flange back contact, promoting closure of the switch rail and reducing the force required to set the switch.
For several decades, the lubrication of sliding chairs has been replaced by roller systems that (partially) lift the switch rail when it is moved to the open position. Each switch rail has two or three of these rollers. Proper functioning of a switch rail requires adequate adjustment and good bearing condition of the rollers, which is not always the case.
The bistable mechanism called DeltaSwitch uses a maintenance free rotating block that carries the moving switch rail. The shape of the block is such that it provides two stable end positions to the switch blade. The device is situated between two bearers about halfway between the toe and the heel of the switch rail.
The top of the block ensures that the switch rail is lifted when it is moved horizontally. The potential energy of the lifted switch rail enables it to complete its stroke. Because the block lifts the switch rail more than 6mm, only one device per switch rail is required.
The large active radius of the block and the use of polyamide on a steel bearing shaft ensure that the friction of the switch rail is virtually zero. The protruding lip at one side of the bistable block and the spring mounted on the other side ensure that the block follows the horizontal movement of the switch rail.
Benefits of DeltaSwitch
- Effective means to reduce the friction between sliding chairs and switch rail
- Preventing flange back contact, reducing gauge narrowing in switches and crossings
- Ensures stable end positions of the switch rails
- Lubrication-free, low maintenance solution
- Easy installation
- Low cost