The incident happened close to the Limestone Road in Limavady, on Monday, April 12.
Detective Inspector Peter McKenna said: “At around 9.00pm that night, a vehicle was set on fire and placed on the railway tracks, forcing an approaching train travelling to carry out an emergency stop.
“This was a very close call in which death or serious injury could have occurred.
“And it has been extremely traumatic for the driver, their swift actions certainly led to tragedy being narrowly avoided.
“Our investigation into this reckless incident continues and we are making a renewed appeal to any witnesses or anyone who may have information that could assist us with our enquiries.
“I am also grateful to the independent charity Crimestoppers, who are offering a reward of up to £3,000 to anyone providing information directly and anonymously to Crimestoppers which leads to the arrest and conviction of any person or persons linked to this incident.
“I want to appeal to anyone who was in the area that night and who saw any suspicious activity, or anyone who may have captured any suspicious person/persons in the area on their dashcam to call us.
“I would also appeal to anyone out cycling in the Duncrun Road area shortly before 9pm or who has information they believe may assist our investigation to pick up the phone and tell our detectives at Coleraine what you know by calling 101, and quote reference 1945 of 12/04/21.”
“Alternatively, to stay anonymous, contact the independent charity Crimestoppers on Freephone 0800 555 111 or complete their simple and secure anonymous online form at crimestoppers-uk.org .”