BURLINGTON, Ont. - The head of Via Rail is telling Canadians train travel is safe following a derailment that killed three engineers.

Via president and CEO Marc Laliberte visited the site of Sunday's derailment in Burlington, Ont., west of Toronto.

Laliberte says while the crash that killed three and injured 45 passengers is "tragic" it is a rare occurrence, adding "rail travel is still very safe."

Hundreds of non-fatal derailments are reported each year, the majority of them involving freight trains on secondary lines. Fatalities on passenger trains from derailments are not common.

The most recent deaths recorded aboard a Via Rail train were in 1999, when two engineers were killed after a train jumped the tracks and plowed into parked freight cars in Thamesville, Ont.

Two of the engineers killed Sunday were experienced drivers, each with more than 30 years in the industry, Laliberte said. They were joined in the cab of the locomotive by a trainee, and investigators haven't ruled out the possibility that the trainee was driving at some point.

Laliberte says it's too early to speculate on the cause of the crash, which occurred as the train was switching tracks.

Peter Snarr, 52, and Ken Simmonds, 56, both of Toronto, were veteran locomotive engineers with decades logged at CN and Via. Patrick Robinson, 40, of Cornwall, Ont., was in training.

Although Robinson was said to be observing "as part of his familiarization program" when the accident happened, "it's possible" he was driving at some point, said Transportation Safety Board investigator Tom Griffith.

"It would have been under strict supervision from the other two locomotive engineers," Griffith added.

Earlier Monday, Via said Robinson was taking part in "observation training, he was looking."

But spokeswoman Michelle Lamarche added later she couldn't confirm who was at the controls at the time of the crash, saying the company will have to wait for the board's report to know exactly what happened.

CN says it investigated the tracks before the crash and found no signs of deterioration or wear.

"It was last inspected on Sunday morning, before the incident, and no issues were found," said CN spokesman Jim Feeny said, noting that particular stretch is given a once-over at least twice a week.

In-depth tests that would reveal hard-to-see flaws are performed several times a year, including the morning of the crash, he said.

The train's black box has been recovered and is being examined by the Transportation Safety Board. The Ministry of Transportation and CN, which owns the track, are also on the scene.

Griffith said it's too early to speculate on the cause of the crash, but promised the board will look into every possible factor, including speed.

"The download (from the box) will tell us exactly what was happening, what the crew was doing on that locomotive," he said at the scene.

"It will tell us the speed, it will tell us the brake pressure, tell us when the brakes were applied, whether he was blowing the whistle," he said.

Unlike a plane, the locomotive didn't have a voice recorder or a camera.

The speed limit for a passenger train along that corridor is about 130 kilometres per hour, but trains are required to slow down while switching tracks, he said.

Train 92 was travelling from Niagara Falls, Ont., when it left the tracks around 3:30 p.m. on Sunday in Burlington -- about 100 metres from where a freight train derailed some four years ago.

The train's manifest listed 75 passengers but emergency officials have said they couldn't confirm whether it was accurate.

The locomotive and one passenger car flipped onto their sides and crashed into a small building next to the tracks. Another two passenger cars were forced off the rails and came to rest in an L-shape.

In all, 45 were admitted to hospitals to be treated for injuries ranging from minor to a broken leg, a back injury and a heart attack, Via officials said.

Halton paramedics reported ferrying 32 people to area hospitals. Another 10 patients were carried by Toronto EMS to the Credit Valley Hospital and Trillium Health Centre in Mississauga.

All but eight people had been released from hospital by Monday afternoon, Via said.

Trains will continue to be detoured or replaced by chartered bus service on the Toronto-Niagara Falls and Toronto-London-Windsor routes.

GO commuter trains were unable to service the Aldershot station for the Monday morning rush as a result of the crash and were being re-routed through Burlington. Aldershot remained closed until further notice, with a bus shuttle service operating in both directions.

Ontario Premier Dalton McGuinty offered condolences to the families of the victims.

"It's going to be very important, of course, that we work together with the federal government now to pursue whatever inquiries, investigations are necessary to ensure we better understand what exactly happened here so we can take steps to ensure it's not repeated," McGuinty said.

"I'm very confident that (GO trains) are safe. Heroic steps have been taken this morning to ensure that the lines are available for passenger use."

NDP Leader Andrea Horwath also stressed the importance of learning from the tragedy.

"As time goes by and we learn what happened, we will work to make sure that Ontarians can travel safely in our province."