The suicidal ex-cop who hacked his former girlfriend to death with a machete Thursday survived jumping in front of a Manhattan train afterward — but lost his legs, police said.

Former NYPD Officer Arthur Lomando is accused of killing 48-year-old Suzanne Bardzell outside her Midland Park, NJ, home at around 3:30 p.m. Thursday.

First responders found the mother of two teenage boys dead behind the wheel of her Volkswagen SUV with the engine still running.

An hour later, Lomando leaped into the path of a train at the 168th Street/Amsterdam Avenue station in Washington Heights, police said.

He was taken to Harlem Hospital, where doctors were able to save his life — but not his legs, which were severed above the knee, cops said.

Lomando was fired by the NYPD in 2004 after 10 years, partly over mental-health issues, records show.