He’s off the rails!

Gov. Cuomo’s micromanaging of the city’s subways has left Andy Byford — the man credited with bringing the system back from the brink — sidelined and deeply frustrated.

“I think he really wants to be left to the do the job he was hired to do,” said MTA board member Andrew Albert. “He knows what needs to be done here, he’s done it in three other world cities and he’s got a plan to get these things done.”

“Look what they’ve managed to achieve: They’ve been able to get on-time performance almost up to 80 percent and that’s been unheard of for years,” Albert added.

Byford’s fans are legion inside the MTA and among the city’s straphanger advocates.

“Andy wants to do his job… If he ends up being somebody forced into a role he didn’t sign up for, we’re going to lose him,” said Nick Sifuentes, executive director of the Tri-State Transportation Campaign.

City Council Speaker Corey Johnson — who’s called for city control of the subways — joined the chorus boosting Byford on Friday.

“Losing Andy would be a tremendous loss,” he wrote on Twitter. “In Andy We Trust.”

Byford found himself sidelined after Cuomo shelved the MTA’s long-planned shutdown and reconstruction of the L train tube, opting instead of a patch-job recommended by college professors with little transit experience.

Sources said Byford was outraged by Cuomo’s February speech to a major civic group, the Association for a Better New York, where he mocked the MTA and its employees for, among other things, using store-brand detergent to clean subway stations.

“Talk about punching down,” said one source.

And Cuomo has repeatedly attacked Byford’s plan to replace decades-old and oft-broken signals with the computer control technology used in London and Paris.

Experts say the overhaul is needed to fix the root of much of the subway system’s operational dysfunction, but the project is pricey and would require months-long line closures in some cases.

Instead, Cuomo frequently touts not-ready-for-primetime technology that would line the tunnels with super high-frequency radio repeaters, which he claims would save time and cut disruptions when compared to rewiring the tunnels.”

“I feel that every sentence that praises Andy Byford shortens his life-span with Governor Cuomo,” said one MTA insider. “Every time, I hear a compliment for Andy Byford, I see another knife in his back.”

“The governor can’t stand a competitor for praise,” the source added. “It’s really a very bad situation, but Andy takes it well.”

Byford said Friday he wasn’t going anywhere, despite the frustrations.

“I love New York, I love this job, I believe in this system, I believe in this agency, and I’m here for the very long haul,” he said in a statement.

Cuomo’s office pointedly did not deny that tensions simmered for months before winding their way into a New York Times story on Friday, which reported the pair haven’t met since January.

“The Governor has been negotiating the state budget since January that included a major MTA reorganization and historic mass transit funding agreement,” said Cuomo spokeswoman Dani Lever. “We do not understand your fixation with personal drama.”

She added: “And yes, everyone finds the MTA frustrating.”

Byford boosters had just one message for Cuomo.

“This is like James Dolan landing Kevin Durant and then trying to bench him because he’s getting too much credit,” said government watchdog John Kaehny, who heads Reinvent Albany. “The guy needs to be allowed to do his job.”