At least 74 persons, four in critical condition, were injured when 10 coaches of the Kaifiyat Express derailed in Auraiya district of Uttar Pradesh on Wednesday morning, police said.The incident took place after the train bound for New Delhi from Azamgarh in Uttar Pradesh hit a dumper, which had overturned on the railway tracks between Achalda and Pata stations around 2.40 am, a railway official said.