Police are investigating whether a 71-year-old woman in a wheelchair who fell on to railway tracks at Southend was pushed, it has been disclosed.
The incident happened at Southend station in Essex when the wheelchair rolled off a platform.
A railway worker who helped rescue her has been suspended and faces a disciplinary hearing.
British Transport Police is urging anyone who was at the station at the time of the incident, on Wednesday August 28, to come forward.
Detective constable David Bishop said: "The woman, a 71-year-old from Benfleet, was at the station with a friend, around 6.20pm, waiting for a train. Suddenly her wheelchair began to roll off the platform and on to the tracks.
"The woman was removed from the tracks and taken to Southend General Hospital, where she currently remains with a fractured hip."
Officers are keen to speak to anyone who may have saw the women fall on the tracks or the moments leading up to the incident.
Police said one line of inquiry is that she may have been pushed.
A spokesman for the train company c2c said: "We have strict rules regarding the safety procedure for the quickest way of stopping trains in an emergency. An employee has been suspended while our investigation into this incident continues."
Rail Maritime and Transport union general secretary Bob Crow said:
"Clearly it is a travesty of justice that a member of staff has ended up threatened with disciplinary action for helping avoid a potential tragedy at Southend and RMT is calling on the company to recognise the strength of feeling this case has generated amongst both staff and the public.
"RMT is representing our member and will do all that we can to ensure that he is returned to work as soon as possible with no stain on his record and a recognition that station-based rail staff play a crucial role in ensuring public safety."