A 5-year-old girl whose father jumped in front of a Bronx subway train while holding her on Monday miraculously survived virtually unscathed — even though the dad’s body was “cut in half,” cops and witnesses said.

The incident happened around 8 a.m. at the elevated Kingsbridge Road station in the Kingsbridge Heights section of the borough, authorities said.

The Manhattan-bound 4 train screeched to a stop over little Ferni Balbuena at the Kingsbridge Road station at around 8 a.m., allowing her to crawl along the track bed to a good Samaritan’s outstretched arm.

Hours later, she left a hospital without any visible injuries.

“She’s OK,” her mother, Niurka Caraballo, 41, said outside Jacobi Medical Center, gesturing to the girl, who flashed a bright smile even as the mom was unable to hold back tears. “Thank God!”

Caraballo said her husband, Fernando Balbuena, 45, had shown no signs of trouble hours earlier when he got up, got dressed and left the family’s Grand Concourse apartment to bring their daughter to school like any other day.

But when the dad — who had been hospitalized for mental-health issues six times and took medication, a police source said — reached the station, he placed a troubling phone call to Caraballo.

“She couldn’t understand what he was saying,” said Luis Sanchez, a godfather to the couple’s 2-year-old son.

“But she got the feeling that something was very, very wrong.”

Caraballo told cops that she repeatedly tried to get her husband back on the phone, but that there was no answer, according to a high-ranking police source.

When she finally got someone on the line, it was Ferni, saying that “Daddy was crying,” the source added.

Caraballo took off running the five blocks from the apartment to the station, but by the time she got there it was too late.

With dozens of rush-hour commuters looking on in horror, Balbuena had scooped up his daughter and jumped into the path of the train rumbling into the elevated station.

Witnesses said Caraballo’s body was “cut in half,” while Ferni was almost completely unharmed.

“I watched as that train came around that corner, and I saw as the man jumped, and I see the little feet hanging out,” said witness Jennifer Hub, a mother of four on the way home after dropping her youngest off at school.

Once the train ground to a halt, two good Samaritans, including Bronx construction worker Jairo Torres, wasted no time in lowering themselves onto the track.

“I see the baby and I jump. I don’t think,” said the hero hardhat, 36. “It’s about the baby, not me.”

With witnesses recording the emotional scene on cellphones, Ferni — still wearing her pink backpack — began to belly-crawl out from under train and toward Torres’ outstretched arm.

“Little by little, my love!” one onlooker can be heard shouting between sobs in one video as the girl inched toward daylight. “Little by little!”

The only sign of possible injury was a small trickle of blood dripping down Ferni’s forehead.

But the emotional wounds were apparent, with video capturing the sound of her wails.

It appeared the girl didn’t grasp what happened. She told her mother that they “fell onto the tracks,” another NYPD source said.

Caraballo struggled to understand the suicide.

“He was a good husband, a good father, a good provider and a good man,” she said through a Spanish translator. “I had no idea [this would happen].”

After a precautionary checkup at Jacobi Medical Center, Ferni was all smiles as she posed for photos with cops, and they presented her with a few gifts, including an NYPD baseball cap and a Little Mermaid doll.

“Can I take these home?” she asked Caraballo, who said with a loving laugh, “Of course.”

Back at home, Caraballo reiterated her gratitude to have her child there with her.

“My daughter is in perfect condition, thanks to God,” she said. “To those living angels that saved my daughter, thank you.”

Additional reporting by Joseph Konig and Israel Salas-Rodriguez