In his preliminary report the Chief commissioner of railway safety, Dr M Mani, who conducted the statutory probe, said the ``accident is categorised as the failure of railway staff''.

``However, the `mens rea' (criminal intent) behind the failure of staff needs further investigation'', he said.

Dr Mani said the accident on August two, resulting in deaths of over 280 passengers, had occurred ``due to the disregard of the non-interlocked station working rules by the Kishanganj east cabin staff.''

This, the report said, ``had resulted in 5610 Avadh-Assam Express being diverted on the down main line (instead of nominated up main line).

``The said train continued its onwardjourney on the wrong line, due to further negligence and lack of alertness on the part of the crew in-charge of the train as well as the station staff at Panjipara, the next station to Kishanganj, and finally entered the down main line at Gaisal where 4055 Brahamaputra Mail was correctly admitted on through signals, resulting in the disastrous head-on collision.''

Dr Mani said the ``accident is categorised as a failure of railway staff. However, it needed further investigation.''