More than half of $1 billion slated for BNSF Railway Co. improvements along its Northern Corridor will be spent in Montana and North Dakota, largely to expand capacity and make track improvements as the boom continues in the Bakken oil fields.

Some of the projects to help expand capacity and improve traffic flow for both freight and passenger trains on the northern route already are well underway.

“Following our record capital investment in 2013 of $4 billion, we are making the most significant capital investment in our history of approximately $5 billion [nationwide] this year,” Carl Ice, president and chief executive officer of BNSF Railway, said in a prepared statement.

“Our capital investments along the Northern Corridor are critical to expanding our capacity to support the region’s rapidly growing economy, improving our ability to meet our customers’ expectations and ensuring our railroad remains the safest mode of ground transportation for freight.”

 In Montana, BNSF plans to invest approximately $160 million to expand rail capacity and replace and maintain the network infrastructure. The railroad also will continue implementing Positive Train Control technology, a life-saving innovation that will make train travel safer.

BNSF plans to hire more than 450 employees in Montana this year; about 200 of those additional workers already have been hired year-to-date, BNSF Railway spokesman Matt Jones said. About 50 of the new hires are positions in Northwest Montana.

“The majority of the hires throughout the state are in train service, but positions to be filled also include track maintenance and mechanical work,” Jones said.

BNSF had 2,300 employees in Montana at the end of 2013.

Montana projects include:

•  Extending track lengths at train yards in Glendive and Forsyth.
•  Constructing a siding between Marsh and Terry.
•  Extending train sidings at Beaver Hill, Blatchford, Hodges, Hysham and Rosebud.
•  Upgrading to Centralized Traffic Control and extending a train siding at Terry.
•  Surfacing and undercutting more than 900 miles of track.
•  Replacing about 60 miles of rail.
•  Replacing more than 145,000 ties.

BNSF will spend $400 million in North Dakota, including construction of a second mainline track between Minot and Glasgow. New sidings will be built between Fargo and Grand Forks, Fargo and Minot, Bismarck and Glendive and Minot and Grand Forks.

Other major railroad improvements are planned in Washington, Minnesota and Illinois.

Burgeoning freight loads along the Northern Corridor — stretching from Chicago to the West Coast — prompted Amtrak to modify its Empire Builder passenger train schedule in mid-April due to freight train congestion.