An investigation into the circumstances leading to a man's death at Preston railway station continues on Wednesday.
The station was evacuated on Tuesday evening with the 33-year-old man understood to have been electrocuted.
British Transport Police said it has now referred itself to the Independent Police Complaints Commission (IPCC).
The identity of the man has not been released with officers yet to inform relatives.
A spokesman for BTP said: "Officers from BTP were called to the station shortly before 9.30pm to reports of a person shoplifting. They attended the station and spoke with a man.
"That man left the officers and, in the following period, is believed to have come into contact with the overhead lines above a freight train in the nearby depot.
"His death is currently being treated as unexplained. Officers are working to inform the man’s next of kin."
The station was evacuated and eyewitnesses reported an 'explosion'.
The incident led to widespread disruption on the rail network with no trains stopping at the station and passengers reporting lengthy delays.
Virgin Trains, which runs the West Coast mainline tweeted: "Due to the emergency services dealing with an incident at Preston all lines are closed."
The line was reopened shortly after midnight and Virgin said all lines were open on Wednesday morning.