The northbound CTrain was shut down for several hours in northeast Calgary after a man was hit by the train near Rundle Station on Thursday.
The incident took place shortly after 8:00 a.m. at the intersection of 36 Street and 20 Avenue N.E.
Paramedics assessed the victim, a 44-year-old man, at the scene and then transported him to Foothills Hospital in life threatening condition.
Police say that the man was walking in the middle of the track when he was hit.
The driver of the CTrain tried to stop and alert the man of the danger, but he did not respond.
"The driver tried to stop the train but was unable to and struck the male," said CPS Sergeant David DenTandt.
Police aren't sure why the man was in the middle of the tracks and why he didn't respond to the driver's alerts.
"It's too early to determine why the male was on the tracks but we are trying to determine that."
Investigators also say that the train involved in the incident was an older model and did not have on-board cameras installed.
"We are canvassing the area, looking for other sources of video."
Calgary Transit reopened the line shortly before noon.
Passengers used shuttle buses and a single train on the southbound track to get past the incident.
DeTandt said they are speaking with eyewitnesses and working to determine the events leading up to the incident.
He adds that safety around and on the LRT tracks is always a big concern.
"It's definitely a concern where pedestrians cross where it is not a designated crosswalk. You can only do so much to stop people from doing that. Definitely people need to cross at the crosswalk because that is what it is designed for; for their safety."