PORTLAND — Federal railroad inspectors are in Maine inspecting tracks that are used to transport crude oil, including those owned by the rail company involved in a catastrophic derailment and series of explosions in Quebec this month.

Inspections will continue through the end of summer, focused primarily on tracks owned by Montreal, Maine and Atlantic Railway and Pan Am Railways that are used to carry tank cars to a refinery in New Brunswick, the Federal Railroad Administration said.

In the past two weeks, the FRA has inspected selected oil-transport routes, said FRA spokesman Kevin Thompson. Those inspections began shortly before the derailment July 6 involving a runaway Montreal, Maine and Atlantic train in Lac-Megantic, Quebec, just 10 miles from the Maine border. Fifty people were killed.

Thompson characterized the inspections as routine, but also said they’ve become “more robust” than usual following the Quebec disaster.

“This isn’t necessarily in response to the Canadian accident,” Thompson said. “But it certainly ties into it.”

The agency regularly inspects tracks, equipment and railroad operations, but these inspections are drawing increased attention because of the Quebec accident, which killed 50 people and leveled downtown Lac-Megantic.

The investigation into the crash has focused on the train’s engineer and whether he properly applied the train’s brakes.

Even if the derailment were caused by human error rather than bad track conditions, it has focused attention on the large volumes of crude oil that are crossing Maine. Mile-long trains last year carried more than 220 million gallons of oil through the state, bound for the refinery in Saint John, New Brunswick.

On top of the federal inspections, Maine transportation officials are reviewing the safety of the state’s 1,100 miles of track and asking the five freight railroads that operate in Maine to submit their policies on how they secure parked trains. The accident in Lac-Megantic happened when an unattended parked train rolled free, gained speed and crashed, triggering a serious of explosions.

Safety is the No. 1 priority, Maine Department of Transportation spokesman Ted Talbot said.

“What we don’t want is an accident like that to happen here,” he said.

FRA inspectors arrived back in Maine on Tuesday to continue their inspections, which are also taking place in other parts of New England, Thompson said. He wouldn’t say where the inspections were taking place or what they’ve revealed so far.

Pan Am Railways Executive Vice President Cynthia Scarano said the latest inspections are nothing extraordinary. FRA inspectors are constantly inspecting the company’s railroad cars, tracks, paperwork, drug-and-alcohol programs, dispatchers and other operations, she said.

“There is on average at least one inspector, sometimes two, on our railroad daily,” she said.

Pan Am checks its own tracks on a daily basis, she said, and once a year hires an outside company that uses a rail flaw detector car that inspects the tracks, including the inside of the rails.

The president of Montreal, Maine and Atlantic Railway, based in Hermon, didn’t immediately return a phone call.

Talbot said generally speaking, FRA inspections look at four broad areas: track structure including rails and cross ties; track geometry, which includes the tracks’ alignment, curvature, surface and gauge; roadbeds, including ballast, drainage and vegetation; and track inspections, which looks at the frequency and quality of the railroads’ inspections and record-keeping.