The Transportation Safety Board of Canada wants voice and video recorders installed on all trains across the country, and it's calling on Ottawa to make them mandatory by law.

In the agency's official rail safety investigation report released Monday, it said that the recordings could lead to increased safety and more in-depth accident investigations.

"There are safety benefits of having such technology on board locomotives, not only for the TSB when we investigate train accidents but also for companies," said Jean Laporte, the TSB's chief operating officer.

"They could draw some important safety lessons and take proactive actions before accidents happen."

Laporte said that while airplanes are equipped with black boxes, trains have no devices that can help investigators figure out what caused a crash.

He said that until recorders are installed, only the conductors know what's happening inside the cab of trains.

But some rail industry experts say the TSB's recommendation wouldn't prevent another disaster like the one in Lac-Mégantic, Que., from occurring again.

Smoke rises from tanker cars in downtown Lac-Megantic, Que., on July 6, 2013. (Paul Chiasson/Canadian Press)

In July 2013, a train carrying oil tankers derailed and exploded in the centre of the town, killing 47 people and demolishing the downtown core.

Bruce Campbell, a rail safety expert and visiting fellow at the University of Ottawa, said the TSB's recommendations don't go far enough.

Campbell is doing research work on oil transport by rail and the Lac-Mégantic disaster.

"If you're asking me if this is the kind of safety improvement that is needed to prevent Lac-Mégantic, I would have to say no. I think there are some much more significant improvements in rail safety that are needed to deeply reduce the risk of another Lac-Mégantic," Campbell said.

Canadian Pacific Railway also said that while it agrees locomotive voice and video recorders should be mandatory in all trains, the recommendation doesn't go far enough.

In a statement issued late Monday, CP president and chief operating officer Keith Creel said, "While I commend the TSB for the work they have done on this issue, today's report does little to improve rail safety."

CP says rail companies should be allowed access to the recordings anytime — not only to the TSB after an incident.

"For it to be effective, it needs to be proactive," said Martin Cej, CP's assistant vice-president of public affairs and communications.

"So for example, if ... a manager looking at a crew's performance on any given day finds a crew member texting — which you cannot do, obviously, while you're running a train — or on their personal phone, or, heaven forbid, sleeping, you can then apply disciplinary measures. If we can identify crew members before that sort of behaviour results in an incident, then we're preventing an incident."

"Not allowing [recordings] to be used proactively is like giving highway police officers radar guns but not permitting them to hand out speeding tickets," Creel said.

Invasion of privacy, union says

Meanwhile, the union representing locomotive engineers and conductors is concerned about spying and reprisals.

In November 2014, when Via Rail announced it was voluntarily starting a pilot project to begin installing recording devices in all its trains, the union filed a grievance.

It was mainly concerned about the possibility that rail companies would have access to the recordings to monitor employee performance and behaviour.

"It's like big brother looking over your shoulder," Bill Michael, the union chairman representing VIA Rail engineers and conductors, told CBC News at the time. "It'd be like sitting in your office and having somebody stand behind you all day."

Transport Minister Marc Garneau said Monday he considers rail safety a top priority and that he will review the report carefully before making a decision.