It came down to the wire, but Congress moved Wednesday to grant American railroads the time they need to get something called Positive Train Control up and running. In doing so, it avoided the prospect of a nationwide halt in rail service by the end of the year.

Congress moved in 2008 to require Positive Train Control, a system that warns a train’s engineer of coming danger. If the engineer does not slow, the train takes over and does it for him. Had PTC been in place in May, a deadly Amtrak crash in Philadelphia could have been avoided and eight lives saved. The system was to have been in place nationwide by Dec. 31.

It has been clear for several years that meeting the deadline was likely to be impossible.

According to the Government Accountability Office, which issued a report on the subject in 2013, the technology for PTC had not been fully developed when the law passed. Even today, not all the various components of PTC are ready to be put to use.

A nationwide PTC system on some 63,000 miles of track doesn’t come cheap. To date, railroads have spent nearly $6 billion on the system.

As for the deadline extension, it included a three-week extension of funding for a surface transportation highway bill. It gives railroads until the end of 2018 to get PTC up and running, with the possibility of another extension if it’s required.

That means that Burlington Northern Santa Fe, the railroad that serves Central Oregon, will not shut down after Halloween, as it had said it would. It means Amtrak will continue to run nationwide, and that goods will continue to move around the nation by rail in a relatively clean and inexpensive fashion.

And it means the national economy, which is not in recession but equally not in a dramatic growth spurt, will be spared the $30 billion loss the American Chemistry Council estimated a shutdown would cost in its first month. That was a pain worth avoiding.