TORONTO, JULY 19: Transport Canada won’t say what the minimum requirements are for making sure a parked train won’t roll away and it won’t disclose the rules set by the rail companies for keeping unattended trains with potentially dangerous goods stationary.

The CBC asked Transport Canada to clarify the rules for tying down a train a few days after the Lac Megantic tragedy. More than two days later, the response ignored the specific request for minimum requirements and referred to the Canadian Rail Operating Rules.

The guidelines in the CROR, however, lack specificity on parking trains.

Section 112, on "Securing Equipment", says: "When equipment is left at any point a sufficient number of hand brakes must be applied to prevent it from moving. Special instructions will indicate the minimum hand brake requirements for all locations where equipment is left."

The section goes on to discuss parking a train on a siding, and to specify that hand brakes need to be fully tested before they can be used to secure equipment.

Eight days after the initial request, Transport Canada continues to rebuff CBC's inquiries with vague answers.

"The rules provide specific instructions for the use of hand brakes to prevent the train from moving when equipment is not in use," it said in an email to CBC.

"Each railway has instructions that further specify how many handbrakes are applied. These instructions also govern special circumstances such as a grade. The handbrake requirements are not load specific. Requirements are determined by the amount of cars, terrain, etc."

NDP MP Olivia Chow said that's not good enough.

"Canadians need to know that the trains coming through their neighbourhoods are safe," Chow said on Thursday.

That's why the Conservatives should not hide the operations of these trains, said Chow, vice chair of the House of Commons transport committee.

"If there's nothing to hide, come clean. Tell Canadians what the operations are and whether they are safe or not."