Full Steam Ahead with Moeller's T0 Isolator Switches!

B1 locomotives were originally designed by Edward Thompson as a mixed traffic locomotive for general passenger and fast freight duties and were built between 1942 and 1952 by a number of manufacturers including the LNER works at Darlington. This particular steam locomotive is one of only two B1’s saved for preservation and it sometimes operates on the mainline between Grosmont and Whitby. As a result it has to be fitted with an Automatic Warning System (AWS) and Train Protection and Warning System (TPWS) which are now mandatory for mainline operation in the UK.

AWS gives the train driver an audible tone and visual indication as to whether a signal ahead is green (clear), red (stop) or yellow (caution). If the signal being approached is displaying a restrictive aspect (red, yellow or double yellow), AWS will sound a horn continuously until the driver pushes a button to acknowledge it. However, if the button is not pressed within three seconds, the train’s brakes are applied automatically bringing the train to a halt. TPWS is an enhanced version of this which applies the brakes if a train approaches a red signal too quickly or attempts to pass it. In this situation, the driver cannot cancel the braking action. Heritage locomotives running on a mainline also have to be fitted with OTMR (On Train Monitoring and Recording) equipment which, like an aircraft’s black box flight recorder, records essential vehicle and journey information including the state changes of all monitored signals.

However, the AWS/TPWS and OTMR systems fitted to LNER’s B1 locomotive only need to be operational when it is running on the mainline and this is where Moeller’s isolator switches come in. Two of Moeller’s T0 switches have been fitted in the cab to enable the driver to easily switch the systems on and off when appropriate. For such an application, the compact and robust design of the T0 rotary switches is ideal.

Moeller’s T0 range can be used for a number of different switching and control functions such as On-Off switches, main switches, main circuit/auxiliary circuit control switches and instrument selector switches. Through their adaptability, versatility and high degree of safety, such as finger proof terminals and clear operating state indication, the switches in the T0 range can be used for a wide range of applications.

All switches can be fitted in standard 22mm fixing hole or mounted by 3 hole fixing. This together with terminals located for straight through wiring and screwdriver guides saves time on mounting and wiring.