One day after radically revamping the MTA’s L-train plan, Gov. Andrew Cuomo apparently decided he needed to undermine confidence in his leadership of the subway system.

In a conference call with the press, he bragged of his next big idea — calling in Elon Musk for technology to upend the MTA’s plans to upgrade its signal systems.

He explained his Musk maneuver by complaining that the MTA is beholden to a “transportation-industrial complex” controlled by backward-thinking consultants and contractors who hold it hostage to outdated tech.

Huh? If there’s any truth to that, Cuomo has full power to change it — because, for all his repeated and ridiculous denials, he has controlled the MTA for eight years now.

He dominates the agency’s board and picks its top executives. When he says frog, its leaders jump, wisely or not — as they did in diverting resources to meet his deadline for opening the Second Avenue line in time for a 2016 New Year’s Eve photo-op.

That diversion proved the final straw (after years of deferred maintenance) that pushed the whole system into chaos.

Chaos that prompted Cuomo to bring in a whole new leadership team that has stopped the descent and is trying to turn the system around — in part via the signal-replacement plan that the governor dumped all over in that conference call.

His staff clearly realized this was a disaster: Soon after the call ended, Cuomo’s office released a statement “explaining” that the gov is merely calling for a study of a “Tesla-like system.”

Plainly, the governor woke up Friday feeling stung by the skeptics who were daring to question the viability of his surprise L-train plan. But he couldn’t have done a worse job of shoring up public confidence than to effectively attack his own handpicked MTA leadership.

Wasn’t Cuomo promising to be the anti-Trump just a few days ago?