PORCELAIN insulators used to support conductor rails are heavy and suffer from chipping and cracking, but these problems can be avoided by using glass-reinforced plastic insulators developed by Rehau.

Assembled from three adjustable and replaceable GRP parts, the insulators are comparable in cost to porcelain. Two versions are available to suit different rail profiles, and a twist-lock height adjustment allows rapid installation.

As well as being an excellent insulator, GRP is impervious to water and chemicals used on the track. It meets fire specifications for use underground, and the extended dry path makes the insulators well-suited to use in damp tunnels, where water contamination and chemical build-up can cause leakage currents on porcelain insulators.

The insulators have been installed in one Network Rail tunnel which had required the porcelain insulators to be replaced every three months. The GRP units have now been in service for over a year.

Rehau AG &Co, Germany

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