The agency says it won't wait for the final results of its multi-month investigation, which has just begun, to make the recommendations.
It sent Transport Canada two safety advisories asking for a pair of changes — the first being that dangerous goods should not be left unattended on a main track, and also that rail equipment be properly secured.
News of that request came on a day when officials set a new official death toll for the disaster: 47.
The estimated death toll has fluctuated since the July 6 crash, with authorities initially unclear on how many of the people declared missing might actually have been out of town.
Police say they didn't recover any more bodies while conducting searches Friday.
Insp. Michel Forget said that left the official death toll at 42 bodies recovered, with five other people missing and presumed dead.
He said the latest estimate was based on information drawn from different sources. Crews from the coroner's office are now taking a one-day break Saturday after working every day since July 6.
Meanwhile, the Transportation Safety Board asked policy-makers to get to work on immediate regulatory changes.
"As this accident has demonstrated, accidents involving trains carrying dangerous goods can have tragic consequences," said the TSB in one of its letters to the government.
"Given the importance to the safe movement of dangerous goods and the vulnerability of unattended equipment, (Transport Canada) may wish to consider reviewing all railway operating procedures to ensure that trains carrying DGs (dangerous goods) are not left unattended on the main track."
In its other letter, the safety board urged a revision of the Canadian Rail Operating Rule No. 112 governing the securement of parked trains.
It said Rule 112 is not specific enough because it does not spell out how many handbrakes to apply for various weights and types of cargo. It also says that the standard, so-called "push-pull test" does not always accurately show whether the brakes have been adequately applied.
A TSB official told a news conference in Lac-Megantic that it's clear insufficient brake force was applied before a train went slamming into the town on July 6.
He says there could be different reasons for that — it could be mechanical problems with the handbrakes, or a problem with the way someone applied them.
Two weeks ago, an unmanned train belonging to the Montreal, Maine & Atlantic railway carrying 72 cars of crude oil slammed into the heart of Lac-Megantic, setting off massive explosions.
Transport Minister Lisa Raitt, speaking through a spokeswoman, thanked the TSB for its recommendations and asked officials in her department to act.
"Minister Raitt has directed Transport Canada officials to review these on an expedited basis," said Ashley Kelahear said in an email.
The TSB said it had a closer look at 25 tanker cars since gaining access to the blast site two days ago.
"We're continuing to conduct the mechanical inspections of all of the tankers," said TSB investigator Donald Ross. "All of the cars are being examined, being inspected, and measurements are being taken and being documented with a photographic record."
Some tankers are being set aside and certain pieces are being sent for analysis.
The cars being set aside are being captured in 3D laser images by the Transportation Safety Board and their U.S. counterpart, the National Transportation Safety Board.
A 3D view will allow authorities to get a better idea of what happened, Ross said.
As for what was inside the cars, samples have also been sent for analysis, Ross said.
"We've taken samples of the liquefied petroleum product that was being transported and that's being sent for analysis so we understand the specific properties."
The TSB has also inspected the track between the blast site and Nantes, where the train had been parked.
It has met numerous witnesses — including the train conductor, railway company officials and firefighters who were on site.
Ross said they are also looking at official documents, like shipping records and rail journals.
"We are interested in the one-man train operation that existed here as well as the railways' safety management system plan," Ross said.
Ross said there are similarities between the Lac-Megantic accident and previous ones, including an incident near Sept-Iles, Que., in December 2011, when a freight train transporting iron ore had brake problems and went out of control on a slope.
The agency said it also took part in a Quebec provincial police briefing with victims' families and was trying to get information to them as quickly as possible as their investigation progressed.
In Ottawa, the Standing Committee on Transport, Infrastructure and Communities will reconvene for an emergency meeting on Tuesday.
The Opposition NDP had pushed for MPs to meet as soon as possible.
Olivia Chow, the NDP transport critic, said that even though the final results of the Lac-Megantic investigation are months away, there are many important issues that can be tackled.
"We want to work together to make sure the recommendations from the experts — the auditor general and the Transportation Safety Board — are implemented to prevent future tragedies from happening," Chow said in a phone interview.
She suggested the committee could study recommendations made by the TSB over the years.
Also, a 2011 auditor general's report revealed that recommendations made in years previous had still not been implemented by Transport Canada.
Transport Canada was expected to address all the recommendations by April this year, but it has not yet.
Even in the absence of a final report into Lac-Megantic, Chow said MPs could go over some key recommendations and hear from the industry's comments about different recommendations and why they work or don't.
"A road map has already been provided by these experts. It just needs to be followed," she said.
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