As the Southern rail service from London Victoria to Eastbourne travelled through the picturesque East Sussex countryside on Thursday thoughts of disaster would have been far from the minds of the 150 passengers on board.Enjoying the view of the picturesque East Sussex countryside on the hottest day of the year, many on the commuter train would be eager to get home or make it to the seaside.But minutes later they would be left screaming, clinging onto upturned seats and handrails, and fearing for their lives as the train derailed.Two people were left seriously hurt, with 20 injured overall, as three carriages came off the tracks when the train passed over a buckled section of track near Lewes at around 3.54pm.The train had set off from London Victoria at 2.24pm, heading to destination Eastbourne, though was running 20 minutes late due to heat-related speed limits.Witnesses said the carriages appeared to jump in the air before tipping on to the embankment and sliding some distance before coming to a halt.Images taken in the aftermath of the incident showed a long section of track had buckled.Passengers stood on top of the wreckage as they scrambled out of carriages that had upturned close to Lewes rail station.Some could be seen on stretchers being taken to hospital. Many of those who did not require hospital treatment were taken to a local community centre to be triaged.