The Transportation Safety Board of Canada says its investigation into what 鈥渕ay well be the most devastating rail accident in Canadian history鈥� will likely take months, but the agency vowed that it will end with improved rail safety across the country.

In a briefing for reporters Friday afternoon in Lac-Magentic, Que., the site of a train crash and explosion that left at least 28 people dead and another 22 missing, TSB officials outlined their process for investigating the incident.

TSB Chair Wendy Tadros said 20 investigators are at the scene and there are another 10 at the agency鈥檚 headquarters devoted to the investigation, which she said they have made 鈥渙ur absolute top priority.鈥�

Tadros met with both TSB officials and local officials Friday, and promised them 鈥渢he answers they deserve.鈥�

Tadros outlined some of the factors investigators will be looking at, including:

  • the grade of the track.
  • the weight of the train.
  • the number of brakes that were set.
  • the practices and procedures of Montreal, Maine and Atlantic Railway, the company that owned the train.

The agency will also inspect the locomotives and tank cars, take numerous photographs and, with the help of the National Transportation Safety Board, will use 3-D laser scanning to paint a picture of how and why the locomotive failed and the tanks exploded.

The agency will also interview 鈥渄ozens of witnesses.鈥�

鈥淚n the end we will tell Canadians what happened, why it happened, and what needs to be done to ensure it will never happen again,鈥� Tadros said. 鈥淏ut today, we are a long way from there. First and foremost, we need to investigate. There is much we do not know, there are many questions that we need to ask and answer.鈥�

The investigation will probe how a runaway tanker carrying crude oil derailed in Lac-Magentic early Saturday morning, sparking a fire and explosions that flattened a large part of the town. The train had been stopped and secured for the night 13 kilometres away in Nantes.

Tadros said the agency will share all information with the community and the media only after it鈥檚 been verified, but expects to provide a full timeline events 鈥渋n the coming weeks.鈥� The TSB will also update its active investigation website regularly and release accident data on individual railway companies.

鈥淭he outcome of this investigation will be to improve railway safety,鈥� Tadros said. 鈥淭here will be lessons learned. We will clearly point out how railways can be made safer for Canadians and for our towns and cities.鈥�

The update on the investigation came on the day a local church opened its doors to mourners who wanted to pray, lay flowers and light candles.

A team of about 30 counsellors has also arrived in the town to help relatives of the dead.