Dashcom footage showed that the truck was spotted by the train driver within about 250 meters (820 feet) or 6.9 seconds before the collision.
The worst train crash in Taiwan in decades was caused by the truck being in line for just a minute after the crash, with officials saying rescue teams worked to remove the most damaged vehicle.
At least 50 people were killed and more than 210 were injured in what became known as Friday’s crash, which left a car stranded near a narrow tunnel near the east coast town of Hualien.
Investigators said Tuesday that the Taroco Express hit a railroad maintenance truck on the line in a “head-on collision” just moments after entering the tunnel.
Prosecutors are working to determine if the car fell under a steep embankment and the driver failed to secure the parking brake or if the truck suffered any mechanical failure.
Investigators on Tuesday gave an update revealing how close the victims were to avoiding the crash.
“According to our initial estimates, it took more than a minute for the truck to derail and hit the Taroco Express,” said Hong Young, chairman of the Taiwan Transportation Safety Board.
Young told reporters that the driver of the train applied the brakes but the speed of the train – it was traveling at about 120 kilometers per hour (miles4 miles) – could not be reduced in a few seconds to avoid a collision.
He said it was clear from the train’s recording devices that the driver who died in the crash had taken “necessary steps” and “tried his best in the hope of avoiding a crash”.
Second from the collision
Dashcom footage showed the truck suddenly appearing around a turning corner and the train pushed into it and then hit the side of the tunnel.
Officials said the train would have needed a distance of 60,000 meters (about 2,000 feet) or 1 16.6 seconds to stop completely – but when the truck was spotted it was only about 250 meters (820 feet) or 9.9 seconds, which is the law.
Friday’s accident comes at the start of the Tomb Sweeping Festival, a four-day public holiday when many Taiwanese return to the village to clean up the graves of their ancestors.
Lee E-Xiang, a 49-year-old truck driver, was remanded in custody for the weekend after a tearful apology to the media.
Lee was part of a contracted rail maintenance team who regularly inspected the mountainous eastern train line in Taiwan for landslides and other risks.
Teams at the crash site on Tuesday were able to remove several more damaged vehicles in the tunnel since the crash.
The two vehicles were freed from their side with curved metal furrows.
The car with the pulverized front remained inside the tunnel where several fatalities occurred.