According to a Queensland police media spokesman, the accident occurred about 6.15pm and there was no explosion from the collision.
“The three victims were pronounced dead at the scene; a 53-year-old Rockhampton man, a 56-year-old Rockhampton man and a 21-year-old Gladstone man who was the driver of the vehicle,” Queensland police said on Friday.
The accident is believed to have occurred about 5km from Stanwell.
According to Aurizon, two of its train drivers and a contractor died from the crash.
“They were travelling to a point for a crew change for a coal train,” the rail operator said.
Their names have not been released.
"This is a black day for everyone in Aurizon and our deepest condolences and thoughts go out to the family and friends of the men, and the workmates who were on site at the time of the incident." Aurizon managing director and CEO Lance Hockridge said on Friday.
"They will be sadly missed and our heartfelt sympathy goes out to their families at this deeply traumatic and difficult time. Aurizon is offering our full support to families and work colleagues at this deeply distressing time.
"Aurizon is also assisting Queensland police in every way we can with the investigations to determine the circumstances of this tragic accident. Safety for our employees remains our utmost priority and we must do all we can to better understand what happened."
An investigation by the Forensic Crash Unit is underway.