OTTAWA -- Canada's transport minister is rejecting a host of changes senators have made to legislation aimed at unclogging rail shipments and laying the foundation for a new air passenger bill of rights.

The decision, laid out in a detailed motion soon to be voted on in the House of Commons, is prompting concerns the Liberal government's decision could harm air passengers and shippers, and calls on senators to take a stand if MPs side with Transport Minister Marc Garneau.

The Liberals are asking the House to reject all but a few amendments the Senate made to the sweeping transport bill that would touch on rules governing tarmac delays, who can file complaints about airline service and the use of video recorders in locomotives.

Garneau's motion says that while some issues raised by senators on the passenger rights work are addressed in the bill or through other legislation, language narrowing the use of locomotive recorders would "significantly impact the ability of railways to ensure the safety of railway operations."

Those amendments that are set to survive are related to the shipping of agriculture products.

Garneau will provide detailed rationale for the government's stance during debate on the motion scheduled for Wednesday.

Gabor Lukacs, founder of the advocacy group Air Passenger Rights, said he plans to lobby MPs and senators not to rubber-stamp the government's motion, warning that doing so could have electoral consequences for those seeking re-election in the 2019 federal vote.

"We hope that after all, sober second thought will prevail," Lukacs said.

The upcoming vote on the motion is latest chapter in a months-long political battle between Garneau and the Senate over the bill, known as C-49, that would make changes to how goods are shipped along rail lines, and direct a federal agency to consult and craft an air passenger bill of rights.

Garneau had urged senators last year to pass the legislation quickly, citing high-profile tarmac delays at Ottawa's airport last year among others as reasons for fast legislative approval. The government is under pressure to get moving from grain farmers and mining and forestry companies believing C-49 could help end ease a backlog of rail shipments.

The Mining Association of Canada is asking Garneau to not kill one of the proposed changes that deals with disputes over shipping costs, arguing that the industry would suffer if international customers don't believe they can get goods on time.

The House and Senate must agree on the same wording of a bill before it can become law; rarely have unelected senators taken a legislative stand when their beliefs clash with the will of the elected House of Commons.

The chairman of the Senate's transport committee believes the Liberals will use their majority in the House to strike down and tweak the Senate's amendments and that the Senate won't draw a line in the sand -- but not before a potentially lengthy debate.

"We'll have our debate and then we'll pass the bill,"said Sen. David Tkachuk, a Conservative.

"The bill has been in progress for a long time and they'll pay the political consequences on where they got it wrong."