On New Year’s Day, 70,000 miles of the country’s railway system could come to an unprecedented halt—leaving millions of commuters without a ride and slamming the brakes on freight service.

At issue is a safety law deadline the industry has struggled to meet. The Rail Safety Improvement Act, passed in 2008, set a Dec. 31, 2015, deadline for most commuter and freight trains to be overhauled with Positive Train Control -- a new GPS monitoring and safety network aimed at preventing deadly accidents like the recent Amtrak derailment in Philadelphia that left eight dead.

The rail industry got a start, spending $6 billion so far, but now warns it can’t make the year-end deadline. As it stands, trains caught intentionally operating after Jan. 1 without the new gear could be charged up to $25,000 per offense. For now, the railways warn they plan to keep their trains parked starting Jan. 1 if they don’t see new legislation making it legal for them operate without the technology.

In a letter to the Senate, the heads of two of the largest railroads in the country said they can’t get the complex project done in time.

“Despite our best efforts, we will not make the installation deadline,” wrote Lance M. Fritz, the CEO of Union Pacific Railroad.

Carl R. Ice, the CEO of BNSF railway, echoed the comments, writing “we still require ongoing installation and extensive testing.”

The looming deadline is of great concern in rail-hub cities like Chicago, where 300,000 commuters ride the Metra line alone.

"This is not like ObamaCare where you may just be slow in getting your insurance,” said Metra Chairman Martin Oberman. “A glitch in this system has two trains running into each other. So, you can't do it without doing it thoroughly and professionally and correctly and it simply can't happen by the end of this year."

However, there is some light at the end of the tunnel. A Senate bill passed in July would extend the deadline to 2020. Similar legislation was introduced to a House transportation committee on Wednesday.

Committee Chairman Rep. Bill Shuster, R-Pa., says he’s confident the House version will pass quickly and the issue could be resolved within weeks.

"The technology is just not developed enough and we knew this day was coming and it's here and Congress needs to act to make sure that we continue to see our rail system operate,” Shuster said.

The project timeline was adhered to in some cases. The system already is working in some states in the Northeast and in California.

Matt Finn is a Fox News correspondent based in the Chicago bureau. Follow him on Twitter: @MattFinnFNC