 On 28 October 1983 , it was announced that the Hastings Line was to be electrified . Reasons that decided the issue included a commitment by British Rail to eliminate asbestos from all stock in service by 1988 and the increasing cost of maintaining the then ageing Hastings Diesels . The scheme was to cost £ 23 @,@ 925 @,@ 000 . Electrification was finally completed in 1986 , the line was electrified using 750 V DC third rail using standard rolling stock , and the expedient of singling the track through the narrow tunnels . The tunnels either side of Tunbridge Wells Central station were not singled because the fact that the south portal of Wells Tunnel and north portal of Grove Hill Tunnel were at the ends of the platforms meant it was impossible to install pointwork without reducing the length of platform available . A speed restriction was imposed through Wells Tunnel . Parliamentary powers were sought in 1979 to bore a second Grove Hill Tunnel , but there was much opposition from local residents . This , and the high cost , caused the proposal to be abandoned . The track in Grove Hill Tunnel was relaid on a concrete base , allowing alignment to be precisely controlled . 
