The incident took place when the victims- Bunty, Sachin and Vipin were repairing a truck on the expressway, they said.
They were rushed to Kailash Hospital where they were declared brought dead by the doctors.
In another incident at Noida Sector 63 area, a car rammed into a truck, leading to the death of one person on the spot.
Three persons were also injured in the mishap, who were later admitted in hospital, police added.