However, there was one recurring problem that compromised the high reliability of the locomotive and that was low coolant levels, which led to the locomotive shutting down, wherever it was. Not only did this mean that another locomotive needed to be sent to recover the train, it also caused considerable delays and potential costly damage to the engine itself, with subsequent unavailability whilst undergoing repairs.

The coolant tank was fitted with a sight gauge at manufacture on the side of the tank, so that a quick visual inspection could be undertaken each day before the locomotive was used.

There were two problems with this, however- over a period of time the sight gauge would become obscured with build-up from the water and additives used in the coolant system, making it hard to read. This was further compounded by the fact that the engine compartment is very crowded and difficult to access because of low light levels.

These factors combined to make it very difficult to read the coolant level in the sight glass accurately, such that either a reading was not taken, or that it was simply not possible to see the fluid level was low. This led to the locomotive shutting down unexpectedly in service, causing the problems described earlier.


Gill Sensors & Controls Limited
Unit 600 Ampress Park,
Hampshire, UK
SO41 8LW

Tel: +44 (0) 1590 613900
Fax: +44 (0) 1590 613901