Engineers are looking into the Forest Hill sinkhole again and have closed the line between East Croydon and London Bridge.
Thousands of commuters from Brighton and Hove were told to expect cancellations and delays and advised to use alternative routes or other means of transport.
Network Rail said: “A safety inspection of the track near Forest Hill is disrupting trains between London Bridge and East Croydon.
“Thameslink services are unable to run between East Croydon and London Bridge. Trains can run between Brighton and Gatwick Airport. Trains may be delayed by up to 20 minutes or revised.
“Disruption is expected to continue until 6pm.”
It’s not all weary resignation – on Twitter the #foresthill hashtag has been supplemented by #foresthole.
And one commuter said: “There’s a five-day strike next week so – if last time is anything to go by – the trains should be a lot more reliable albeit more crowded than ever.”
@SouthernRailUK are working round the clock on a new sign for #ForestHill station. pic.twitter.com/MRnoBC4vk4
— Michael Hutton (@_hunterfargo) August 4, 2016