A curve that never existed, as far as I'm aware, between Dorking Town (main) station and the Guildford-Redhill line, would provide an alternate route to Gatwick from south west London stations such as Wimbledon and Sutton, as well as directly linking towns such as Sutton and Epsom to Reigate and Redhill (there was once a link between these two lines but it was a West-South link, my idea would be a East-North link)
I don't think it would be difficult to insert now, only a few hundred yards of track and a bit of electrification, and the capacity issues at Redhill are going to be addressed shortly anyhow, apparently
If you look at Google Maps, it looks as if the idea was at least once considered, as the perimeter line of the adjacent housing seems to form a curve between the two lines... (I can't get the google map link to work but if you look at Dorking on the satellite view you'll see what I mean)
I don't think it would be difficult to insert now, only a few hundred yards of track and a bit of electrification, and the capacity issues at Redhill are going to be addressed shortly anyhow, apparently
If you look at Google Maps, it looks as if the idea was at least once considered, as the perimeter line of the adjacent housing seems to form a curve between the two lines... (I can't get the google map link to work but if you look at Dorking on the satellite view you'll see what I mean)