Every night, MTA inspectors walk the subway tracks for miles at a time.

But across a third of the system, the MTA plans to reduce manual inspections from twice weekly to once a week, and increase the deployment of special "Track Geometry Cars" that use high-tech cameras and computers to analyze the tracks.

The Transport Workers Union and MTA Board Member Charles Moerdler warn that the $22 million pilot program could come at the expense of safety.

"Without a doubt, the public will be at risk if track inspectors don't do a physical inspection of this system,” said John Samuelsen, the International President of Transport Workers Union. “Video cameras in this case cannot replace human beings."

Samuelsen said that previous efforts to reduce the number of times that track inspectors physically walk the tracks have been rejected by the MTA's own Office of System Safety as a bad idea.

An MTA spokesman counters that the high-speed cameras can pick up rail flaws more easily than the naked eye, and have the added benefit of being less disruptive to train service because workers are no longer on the tracks.

The spokesman said, "We've proposed a way to use tried-and-true technology to have more thorough inspections, with less risk to track workers and less impact on train operations, at a lower cost — exactly the kind of innovation we need and a win for both customers and our employees. We’re committed to working with our labor partners to realize the safety and efficiency benefits of this innovative approach."

The union says it will wage a public relations campaign to alert riders to what it says is a bad decision.

"These are the tools that a track inspector walks with every night on a five-mile inspection,” Samuelsen said, holding up a wrench and a hammer. “These are the tools that stop a derailment. A video camera has no ability to stop a derailment."

The MTA says video track inspections are common in subway systems across the world, and that the change would save the cash-strapped agency about $4.5 million dollars a year.