A subway motorman broke the rules to get urgent medical help for a trainee who blacked out in his cab and was spitting up blood — and the MTA responded by suspending him without pay for breaching protocol, The Post has learned.

Quincy Calhoun, 59, was training a motorman on the elevated 5 train the morning of April 17 when his student felt chest pain and fainted as the train approached Dyre Avenue.

Before he collapsed in the cab, the ill trainee went through a red signal, which threw the brakes into emergency.

Calhoun, who has been working for the MTA since 1989, said he tried to reach the Rail Communication Center via a portable radio for help, but could not get through since he was in a dead zone.

“I was only trying to do the right thing by that gentleman who was laying in that cab,” said Calhoun. “That’s what I was thinking about. All I know is when you grab your chest and slump to the floor, it isn’t a good sign.”

He went onto the tracks and used a device called a stop arm to disable the signal, and then split a switch to move the train forward.

“All I was thinking about was getting this guy medical help,” said Calhoun.

He said he then pulled into the station at under 10 mph. The trainee was taken by medics to Jacobi Hospital shortly after.

The MTA said the move was dangerous, and immediately took him out of passenger service. Calhoun was then suspended without pay on Monday.

“Even all this stuff started coming down at me, I didn’t feel bad because I knew I had done the right thing,” he said. “All I was thinking about was getting this guy medical help.”

Kevin Harrington, a vice president of rail traffic operations at TWU Local 100, said the trainee would have been in greater danger if Calhoun had waited for the power to be switched off and medics had had to walk out over a thousand feet on the track to rescue him.

“The Transit Authority is being absolutely unreasonable, and it shows their contempt for human life, particularly their employees,” said Harrington, who said he would have done the same thing that Calhoun did.

“This is the most outrageous case in my union career. This is an all-time low.”

The MTA said that the train operator jeopardized the safety of others and could have caused a derailment.

Harrington said that splitting a switch will not derail a train unless the train operator moves it back again.

“The train operator did not follow proper safety protocols by failing to contact the rail control center and obtain permission for this maneuver,” said spokesman Kevin Ortiz.

An MTA official also said Calhoun has past infractions contributing to the disciplinary action.