With chants of “No more delays, Cuomo fix the MTA,” dozens of commuters demanded subway improvements during a “rush-hour rally” outside of Gov. Andrew Cuomo’s Manhattan office Wednesday.

The rally outside 633 Third Ave. was planned in response to the A train derailment at the 125th Street station in Harlem on Tuesday morning that injured 39 people, organizers and city officials said.

The MTA said human error was the cause of the accident, as a replacement rail was not secured properly on the tracks. Two maintenance supervisors were suspended without pay on Wednesday.

“Gov. Cuomo has appointed the new head of the MTA just in time for that new head of the MTA to take charge at the scene of the derailment with Gov. Cuomo nowhere to be found,” John Raskin, executive director for the Riders Alliance, told the crowd of about 40 people.

Jaqi Cohen, campaign coordinator for the Straphangers Campaign, said the derailment was a “dangerous and stark reminder” that the city’s transit system is facing a “crisis point.”

“I’m here today because our city is facing a transit emergency,” Cohen said. “I’m here today because transit riders are sick and tired of risking their jobs, risking their safety and risking their sanity when they step on the subway each day.”

But the rally was also about more than just the derailment. Faced with what feels like endless delays and service disruptions, straphangers are now putting the heat on Cuomo, who oversees the state-run MTA.

“Gov. Cuomo is failing New Yorkers with the subway system and the bus system. You get on the 2 or 3 train, there’s a delay. You get on the A train, another delay,” said Vaughn Armour, with the organization New York Communities for Change, adding that New Yorkers shouldn’t have to play Russian roulette when they get on a train or bus.

Just weeks before the derailment, commuters were trapped in a dark F train with no air conditioning for nearly an hour. One of those straphangers, 36-year-old Michael Sciaraffo, of Bensonhurst, went to the rally to voice his outrage and demand an emergency safety campaign from the MTA.

“I never thought I would find myself on a subway train that was 120 degrees with no way out, with the MTA lying to us about what happened,” Sciaraffo said. “That day was the last straw for me, and at this point something needs to be done about that situation.”

Sciaraffo said he feels the city is living with third-class infrastructure.

“Unfortunately, $2.75 is the cost of the fare, but the cost of our lives is much greater than that, and I do not trust the MTA with my life,” he added.

With Nicole Brown