Ceramic insulating insert

NETHERLANDS: Movares and Corus are testing a ceramic insulation insert for rail joints which promises the electrical insulating properties of plastic components with the lifespan of the adjoining rails. If the tests are successful, a commercial launch is expected within a year.

There are around 5000 insulated joints on the Dutch network, forming an essential part of the signalling and level crossing control systems. These joints consist of a 6 mm gap filled with a plastic insert, held together by insulated steel fishplates. They require frequent maintenance as wheels create burrs on the rail ends which must be removed to avoid short circuits. Most joints are weaker than the rails, thus requiring extra support, and the joints can make for noisy running.

The ceramic insert developed by Movares eliminates the gap between the rails. Careful design ensures the ceramic is always under compression, even at the lowest temperatures. This provides a continuous running surface, eliminating noise-generating discontinuities, preventing the formation of burrs and removing the need for extra support.

The ceramic joints are more expensive than the plastic components, but are expected to have lower lifecycle costs, with negligible maintenance until they are replaced after 15 to 20 years at the same time as the adjoining rails.