NS is making preparations to suspend these services in the absence of a federal extension for the introduction of Positive Train Control (PTC), which under current legislation must be completed by the end of the year.

"Cessation of service - effective across the entire NS rail network - is required to comply with federal safety laws that become effective after December 31, the government's deadline for installation of PTC," NS said in a statement. "Despite investment of nearly $US 1bn to date, NS will not meet the deadline."

NS says the status of non-PIH traffic interchanged with other railways as well as the operation of freight trains on Amtrak's Boston - New York - Washington Northeast Corridor after the end of December is also "currently under review."

"We remain hopeful that Congress will grant the railroad industry an extension of the PTC deadline and appreciate the consideration elected officials and regulators are giving this issue," says NS president and CEO Mr Jim Squires "However, in order to conduct lawful operations on January 1 2016 and beyond, we must plan ahead to clear affected loaded and empty freight cars from our system. NS sincerely regrets the inconvenience that customers, passengers, and commuters will experience. Our strong hope is that Congress will act quickly and decisively to allow us to restore full access to our rail network."

Squires notes that NS is installing PTC as quickly and safely as possible. "PTC is one of the most complex technology implementations in our history," he says. "It is in everyone's interest - railways, customers, suppliers, and communities - that adequate time is devoted to installation, testing, and implementation. NS is committed to getting this right."