A Brooklyn conductor discovered a dead man riding a Crown Heights train during morning rush-hour, cops said.

The 53-year-old man was on a 4 train near Utica Ave. and Eastern Parkway around 7 a.m., according to police.

“The customer was on a southbound train that travels from Woodlawn to Utica,” an MTA spokeswoman said.

The conductor first spotted the man and thought he was sick—but when he realized the victim wasn’t breathing, authorities were notified, the spokeswoman added.

Service was delayed in both directions for about 45 minutes. The Medical Examiner will determine the cause of death.

The identity of the deceased is pending proper family notification.