A MONITORING system based on pressure sensing developed by Smith Industries Hydraulics Company (SIHC) for its own clamp lock point machines has been approved by Railtrack for use across the British main line network. Analysis of the variation of current, time and pressure within the clamp lock system revealed that the rate of change of pressure with variations in load is far greater than with other parameters. The greater rate of change allows diagnosis of deterioration in performance to be more responsive. It is easily analysed, and should reduce the incidence of spurious maintenance calls.

Using pressure transmitters placed in the hydraulic circuit, it was demonstrated in the laboratory and during field trials that repeatable traces for any given set of points could be compared with each other against a ’fingerprint’ set. Comparison of these within the software generated an automatic call-out or allowed engineers to interrogate the system.

Existing SIHC power packs can be modified to include monitoring of pressure and also oil level. The latest clamp lock model can be fitted in-sleeper with actuators producing a higher closure force. Secondary electrohydraulic drives with stretcher-based secondary detection driven by the primary power pack are also available. Condition monitoring can be installed, and the pressure sensors forming the basis of the SIHC system can also be fitted to level crossing barriers.

Smiths Industries Hydraulics Company Ltd, Great Britain

Reader Enquiry Number 147