Caution with batteries

Clive Castle makes a good point about battery-powered locomotives in place of older diesel-powered trains ( Open

Access, RAIL 819). In my career with the National Coal Board, we certainly relied on battery power to operate our fleet of Greenwood & Batley locomotives.

One morning I was preparing to deploy my team. I was stopped by the Undermanager and told to go immediately underground and to hold guard of a defective locomotive at the furthest end of the Trunk Locomotive coal haulage road. I was told not to touch or interfere with the locomotive and to let no one else to do so.

The principal Her Majesty’s Inspector of Electrical Machinery was on his way to examine what had happened.

He arrived with our Electrical Engineer and the Colliery General Manager.

All coal mining equipment was subject to all electrical switching components being inside a sealed enclosure known as FLP (Flameproof), which was safe to operate in an atmosphere containing a small amount of explosive methane gas. Fortunately, the section of the colliery where the defective locomotive rested was not in any appreciable methane atmosphere.

The inspector showed us all a hole through the FLP Container which looked to have been cut out with a thermic Lance. He then told us that two contactors inside the FLP Vessel had frozen in, and had discharged totally the whole electrical energy stored in the ten-tonne Lead Acid Battery, which had discharged within seconds atomising the metal components.

He went on to explain that all batteries could perform in exactly the same way as no one had control of the battery.

Of course, we no longer live in the world of Lead Acid batteries for traction, nor have a coal mining industry, but in his words all batteries could totally discharge given similar circumstances.

If you investigate air crashes the Lithium Ion Battery in the aircraft has been blamed for unsuspected fires. The usual site of the batteries is beneath the Flight Deck.

Battery power is being introduced in the Midland Metro. I would be anxious not to see a battery download such as the one that I saw the effects of at the colliery where I worked.

Richard J. Barker, Warwickshire