Sarawak had never been particularly rich in railways but it was little known that there was an actual railway laid down in an area called Ensalai, near inland of the Baram River near the border of Brunei.
As the oil company expanded its drilling sites throughout Miri, one of such site, Ensalai, lay in the middle of a swamp which could only be reached by laying a corduroy of logs over it, and putting the railway over those logs for vehicles to successfully move through. These railway equipment are brought over from North Borneo (now Sabah). Records show that this was in June of 1960.
The 'passenger train' for this railway was a standard Land Rover, albeit with the standard wheels swapped out for modified wheels. A 3.25 ton locomotive that was loaned from North Borneo Railways was used to carry much larger and heavier equipment.
As for the drill site itself, Ensalai turned out to be a disappointment and was abandoned on Christmas Eve that year.