Officers from British Transport Police have released CCTV images of a man seen walking along the train tracks between Metro stations on the Sunderland line in the early hours of March 1.
The man was seen walking on the tracks at Sunderland station at 5.40am. He was told to get off and climbed back up onto the platform then walked along the platform and went back on to the tracks towards Park Lane Metro Station.
After officers checked CCTV the same man was seen climbing onto the tracks at the Stadium of Light station at 5.19am before walking to St Peters Station, then through the railway tunnel to Sunderland. He then walked along the lines to Park Lane station where he eventually left the tracks.
More top news
With a little help from Santa, the 5-year-old turned on Durham County Hall's christmas lights
Looking back on a turbulent year: Paul Brand and guests discuss Brexit, Trump - and hopes for 2017.
Rail fares in Britain are set to rise by 2.3% next year. Here is how the rise will affect commuters on routes across the country.