The U.S. railroad industry has agreed to slow down oil trains in 46 “high-threat urban areas,” including the Twin Cities, under a voluntary program to enhance the safety of moving crude oil by rail.

The program, announced Friday, is the result of private discussions between the Association of American Railroads and federal regulators. But rail safety advocates said the measures won’t significantly reduce the risks of 100-car-long oil trains.

Railroads said such trains will go no more than 40 miles per hour by July 1 in urban areas. BNSF Railway Co., the major carrier of North Dakota crude oil, said it still has some 50 mph speed limits in the Twin Cities area that now will be reduced. Canadian Pacific said it already operate trains at 40 mph or below in Minneapolis and St. Paul.

The local speed zone includes a 10-mile buffer extending beyond the east and west borders of Minneapolis and St. Paul. In some places, trains already run at even-lower speeds, industry officials said.

The industry announcement comes as railroads find themselves under increasing scrutiny after recent disasters involving oil trains from North Dakota, including the July 2013 crash that killed 47 people in Lac-Mégantic, Quebec, and the Dec. 30 derailment and explosion of a BNSF oil train near Casselton, N.D.

Separate legislative committee hearings on rail safety are scheduled next Wednesday in the U.S. House and Minnesota House, where a state bill to boost emergency response capabilities has been proposed.

Dave Christianson, who oversees rail planning for the Minnesota Department of Transportation, said Friday that he was pleased to see the industry measures.

“At 40 mph, you have a lot less dynamic force when cars are hitting each other,” he said. “It really is aimed at reducing the likelihood of a puncture.”

Canadian Pacific and BNSF said they support the measures. Canadian Pacific spokesman Ed Greenberg said the railroad, whose U.S. headquarters are in Minneapolis, also created a new rate structure that gives crude oil shippers an incentive to use newer, more-puncture-resistant tank cars.

MnDOT says that about eight oil trains roll into Minnesota daily from North Dakota, where 70 percent of the state’s crude oil bounty goes to refineries by rail. About six oil trains, on average, pass through the Twin Cities, MnDOT says.

Jeff Millar, a rail safety advocate in Washington, D.C., said there is no evidence the 40 mph speed or other measures will reduce risks.

“You have got these gigantic crush-and-puncture forces, so if you cut the speed down from 50 to 40, how much of an improvement is that?” he said. “I don’t see that as any kind of a significant gain.”

Railroads also agreed to increase track inspections on oil train routes; add braking capability that can be operated from either end of a train; reconsider the routing of such trains; add trackside monitors to automatically detect faulty equipment, and increase outreach to communities along crude-by-rail routes. The industry committed $5 million to develop a hazardous-material training and tuition program for first responders.

But the training assistance, when “spread out over all the states on oil-train routes, is a drop in the bucket, and it does not address local first-responder equipment needs,” said Paul Blackburn, an environmental attorney who works on pipeline and oil safety issues in Minnesota.

Bruce Glover, general chairman of the Brotherhood of Maintenance of Way Employes in Minneapolis, said railroads already comply with most of the voluntary measures.

“This is not a breakthrough,” said Glover, who contends that BNSF has too few workers to handle routine maintenance of tracks in Minnesota and North Dakota.

In late January, he wrote a letter to BNSF CEO Carl Ice asserting that there is a shortage of track workers in the region.

“Fewer people, with less available track time, are expected to keep more track, with more trains, safe and free from defects,” he said in the letter, which he recently gave to the Star Tribune. “This is a recipe for disaster.’’

BNSF spokeswoman Amy McBeth disputed Glover’s workforce figures in the Twin Cities, but conceded that the railroad has difficulty hiring in North Dakota, where the oil boom has sparked intense competition for workers.

Holly Arthur, a spokeswoman for the Association of American Railroads, rejected criticism that railroads face few burdens under the voluntary measures.

“What this is doing … is putting down what the industry will do voluntarily across the board about the movement of crude oil,” she said. The industry also supports tougher tank-car standards and other safeguards, she said.