On a frosty Boxing day in 1870 the driver of the 16:25 from London King's Cross to Peterborough noticed an 'uneasy oscillation' as he passed over Marshmoor level crossing, 2 miles south of Hatfield station. He peered back and discovered he had lost his train and pulled up. He reversed back, preceded by his fireman on foot showing a red light. They were met by the white-faced guard who told them there had been a disaster.