A broken rail near Hatfield, Hertfordshire, has caused significant disruption to train services, particularly affecting routes between King's Cross and various destinations including Peterborough and Cambridge. National Rail has indicated that delays may extend up to an hour, with repairs expected to continue into the evening of September 2. Services on Great Northern and Thameslink lines have been altered, with some trains being diverted and peak-time services cancelled to mitigate congestion. Passengers are advised to allow extra time for their journeys, as National Rail works with Network Rail to resolve the issue. The disruption is expected to last until the end of the day, with normal operations anticipated to resume by 7 am the following day.