Rail operators have issued a groveling apology after a report into last Thursday's derailment in East Sussex revealed that the track had a pre-existing defect - because, of course it did. The interim report by the Rail Accident Investigation Branch (RAIB) found that CCTV images showed a 'track geometry irregularity' before the incident near Lewes, which injured 30 people. The watchdog even published an image appearing to show the track had buckled, a delightful quirk that can happen in high temperatures.

The report noted 'a sustained period of hot and dry weather' and an ambient air temperature of about 27C at the time, according to the nearest weather station. Because nothing says 'safe railway' like a track that's decided to take on a new shape in the heat.

Network Rail and GTR, the company operating Southern, issued a joint statement saying they were 'very sorry that this happened on our railway.' Lucy McAuliffe, Sussex route director at Network Rail, and John Whitehurst, chief executive at GTR, acknowledged the 'ongoing impact' on customers, communities, and railway colleagues. They insisted that 'safety is and will always remain our highest priority,' which is reassuring, given that a train just fell over.

The stretch of railway between Lewes and Haywards Heath will remain closed until at least the end of service on 26 August. This gives recovery teams time to lift the derailed carriages by crane and preserve evidence - because, you know, nothing says 'we're on top of this' like a two-week closure.

The incident occurred on 13 August during the UK's fifth heatwave of the summer, during which two trains derailed in less than 24 hours. The second derailment happened the following Friday when the rear carriages of a Greater Anglia train came off the track 'in an upright position' at Wickford railway station in Essex, with no injuries reported. At least that one had the decency to stay upright.

The RAIB noted that the embankment near the Lewes site is made of clay, which is 'sensitive to variations in water content and may undergo movement as moisture levels change.' Although there's no evidence of a significant embankment slip before the accident, there is evidence that some movement had previously taken place. Also, passengers on other trains had reported 'rough riding' in the same location - because why would anyone listen to passengers?

The train was traveling at about 65mph (within the 70mph speed limit) with about 150 people onboard. Three carriages ended up on their side, trapping passengers and injuring 30 people, including 20 who required hospital treatment. The RAIB said 'significant damage was caused to the train and to railway infrastructure,' which is a bit of an understatement.

The investigation is taking into account weather conditions, track status, embankment condition, train condition, and the effectiveness of measures to mitigate hot weather. In other words, they're looking into everything that could have been done differently, which is a lot.