I would like to add that the Mainline Electric trains to Brighton are not the same trains or electrical supply equipment as 90 years ago
In Bristol, trams operated electrically from 1895
(link) until 11th April 1941 but we still we await electric trains. They have got as close as South Gloucestershire, with electric trains calling at Bristol Parkway and passing through but not calling at Patchway and Pilning.
One day the wire will extend from Parkway to Temple Meads .............. Wooton Basset to Temple Meads I would say has less certainty