Passengers faced major disruption this morning after a points failures between Gatwick Airport and East Croydon.
The Gatwick Express was suspended, with passengers having to instead use Thameslink or Southern Rail trains.
Services between London and Brighton also ground to a halt after the incident in the Earlswood area on Friday morning.
National Rail said trains were able to run normally shortly after 3pm.
Thameslink services between London St Pancras and Bedford and between Finsbury Park and Peterborough/Cambridge were also disrupted.
Earlier, there was also disruption to South Western Railway services after an "operational incident" at their Strawberry Hill depot.
The rail operator said "as a result, there are fewer trains able to run across the network."
Fuming commuters took to Twitter to blast the much-maligned rail operator, with some holidaymakers even missing flights because of the disruption.
One said: "Missed our flight to Rome thanks to @TLRailUK and the delays to Gatwick!! Luckily thanks to @easyJet who sorting us out a flight for later today quick, easy and with no hassle. Great service!"
Another tweeted: "What a joke! The boards at the station said our train was on time until a minute before it’s due. Now delayed indefinitely. At least give customers realistic expectations at the stations if there is going to be disruption."
A third added: "You could at least give information and announcements at the stations instead of assuming we can all mind read."
