Selective energising of third rail sections

I read with interest the article on the safety and productivity issues relating to maintenance of the third rail on the lines to London Waterloo ( RAIL 868).

I have often wondered if the safety and efficiency of third rail lines could be dramatically improved if each section of third rail was only energised when a train was on the section and drawing power.

When there is no train drawing power, then the section would not be energised.

There are now five tramways in France (Angers, Bordeaux, Orléans, Reims and Tours) which use extensive stretches of third rail embedded in city streets used by pedestrians, that are only energised when a tram is directly overhead and covering the energised section. Could this be adapted for use in the UK?

In the French system, detection loops within the power rail receive a signal from an antenna around the vehicle pick-up shoe which activates the power supply. There are probably many other ways in which this could be done, perhaps using GPS as a trigger, or connecting each third rail section to the internet using ‘Internet of Things’ technology.

Such a system would not only improve safety and maintenance productivity, it could also help to win the safety case for extending third rail electrification to ‘fill in’ lines such as Ashford to Hastings. It could also be used in high-risk locations such as stations and level crossings. Robert Hope, Sunderland