Between approximately 3:26 and 4:05 am (AEDT), Allan Simpson drove a Nissan van along the train tracks 50–68 metres south-west of the level crossing at West Dapto Road, adjacent to Kembla Grange railway station.

[1]: para [15] A northbound NSW TrainLink Tangara train, set T42, bound for Bondi Junction approached the site at 4:09 am.

Just prior to 4:10 am, the Tangara collided with the van while slowing down from approximately 90 kilometres per hour (56 mph), derailing its first carriage.

[5] Initial media reports indicated that the van was stolen[6] and relayed Police concerns that it may have been deliberately left on the tracks to incur damage.

Simpson cut through the fence of the nearby Wollongong Kart Raceway and stole a go-kart, wheeling it to a place adjacent to the train tracks.