Clearly, a solution was required to cure this problem and the answer was to provide an indication in the cab so that the driver could see on starting the locomotive, or during operation, that the coolant level was low. 

Because of the high utilisation of the locomotives and the extended service periods, a sensor was required that would remain operational and accurate over prolonged periods without maintenance, and be unaffected by the high levels of vibration and heat experienced in service.

Gill Sensors & Controls was approached because it offers durable and accurate capacitive liquid level sensors. The sensors are designed using solid-state technology with no moving parts and a tolerance of high temperatures which gives these sensors the reliability to meet the service specification of the locomotive.

Gill Sensors & Controls created a customised version of their standard LevelPro (7010) professional liquid level sensor to meet the application requirements.

The sensor is manufactured from stainless steel at 450mm in length, with an extended 2 metre flying lead with low smoke and toxicity characteristics to meet fire regulations. The flange was also changed to remove the threaded portion to a plain 1” diameter, allowing fastening using the 5 hole SAE fitting. The sensor has a 4-20mA output.

“The adoption of the Gill sensor to monitor the coolant levels has provided certainty and prevented many unnecessary breakdowns caused by a locomotive going out with insufficient coolant” says Simon Peaty, Product Manager. “The fact that we only had to make simple modifications to a standard sensor to meet the specific needs of the installation is testament to the inherent quality and performance of our level sensor product range”.


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

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