WASHINGTON – Promising an "aggressive posture," the head of the agency overseeing railroads urged them Thursday to install a mandated safety system as soon as possible, even after Congress last week pushed the deadline back to 2018.

The safety system, Positive Train Control (PTC), was supposed to be in place by the end of this year, and could prevent crashes like the Amtrak derailment in May that killed eight in Philadelphia. But with railroads behind schedule, Congress gave them three more years, with extensions possible until 2020.

"As railroads contemplate the new PTC deadline, I would urge them to view that new date – three years from now – as the absolute latest moment for implementation. Do not make it your goal, please, to be the last one to cross the finish line in December of 2018," Sarah Feinberg, the newly-confirmed administrator of the Federal Rail Administration, said in a speech to officials representing railroads and related groups. "Make it your goal to beat the deadline, by as much as possible, and as safely and efficiently as possible. The public deserves it, your shareholders deserve it, and the Congress expects it."

Feinberg, confirmed by the Senate last week as part of the deal that allowed the PTC delay to pass, spoke to the Railroad Safety Advisory Committee, which includes representatives from all aspects of the rail industry, including government safety experts, labor unions, commuter and freight lines and businesses that rely on rail, such as chemical, oil and gas companies.

"Over the last year, I am sure you have observed that FRA is in a much more aggressive posture on PTC," Feinberg said. "Everyone should expect for that posture to continue."

She said called the Philadelphia derailment "a stark reminder of what can happen without PTC."

The rail administration will have more details on its approach to the new deadline and expectations for railroads in the coming weeks, Feinberg said.

Under the extension, railroads are required to make yearly progress reports and could be fined for falling behind key benchmarks.

Feinberg had been the rail agency's acting administrator since January.

Commuter and freight railroads have said they are committed to installing PTC, but were hampered by federal regulations, budget crunches and technological hurdles.

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