No drugs were found in the system of a technician of a freight train involved in Saturday’s fatal collision with a public bus in Bangkok, police said on Wednesday.
Toxicology results from Police General Hospital for the technician, identified only as Siriphum, were negative, said Pol Col Kamphon Rattanaprateep, deputy commander of Metropolitan Police Division 1.
Investigators have questioned Mr Siriphum and are continuing to question injured parties and additional witnesses, including motorcycle taxi riders who were near the scene.
As well, testimony has been taken from officers with the prevention and suppression unit at Makkasan police station, who located and detained the train driver on the day of the train-bus collision that killed eight people and injured dozens of others.
Authorities are also examining whether any parties may have violated traffic laws in connection with the accident, said Pol Col Kamphon.
The investigation team is scheduled to question the masters of the Makkasan and Khlong Tan stations on Thursday to examine whether operational procedures were properly followed by the train driver and railway crossing gate supervisor at the time of the incident.
Journey re-enacted
On Wednesday afternoon, police and officials from the State Railway of Thailand (SRT) boarded a train and entered the driver’s cabin to recreate the incident and assess visibility along the route. The simulation covered a stretch of about 9.2 kilometres from Hua Mak to Asok station.
The investigators were divided into two teams. One team observed from aboard the train, while the second monitored operations at railway crossing barriers. The train used was a regular passenger service, with the SRT confirming that operational procedures for passenger and freight trains were identical.
Investigators focused on two main issues during the simulation.
The first involved examining visibility distances for railway signalling systems, including flags and light signals, and the visibility of vehicles obstructing the tracks, in order to determine how far in advance a train driver could detect hazards.
The second issue concerned braking distance, specifically how much distance a train driver requires to slow down and stop before reaching a station or railway crossing.
Investigators also observed how crossing gate operators performed their duties, including at what distance warning signals were given to train drivers. The team additionally monitored train speeds throughout the journey, from acceleration and deceleration to the final braking process.
Police said all findings gathered from the field operation would be carefully reviewed and compared against statements provided by the crossing gate supervisor, the train driver, the technician and railway staff involved in the deadly level crossing collision.
The information will also be measured against SRT operational regulations for both train operators and crossing gate personnel.
In-depth investigation
Investigators are examining operational behaviour in detail, including train speeds, radio communication procedures, the distance at which crossing barriers are lowered, and the use of both light and flag signals by gate operators, in an effort to determine the exact cause of the accident.
On Monday, police filed charges of recklessness causing death, severe injury and physical danger against two state railway workers and a passenger bus driver.
Sayomporn Suankul, the 46-year-old driver of the Laem Chabang-Bang Sue freight train, failed to stop even though a level crossing worker raised a red flag, signalling that vehicles were blocking the crossing on Asok-Din Daeng Road in Huai Khwang district, said Pol Maj Gen Worasak Pisitbannakorn, commander of Metropolitan Police Division 1.
The train driver also tested positive for drug abuse and faces an additional charge.
The level crossing supervisor, Uthen Sornkheeree, 46, was seen in CCTV footage briefly showing his red flag before calmly folding it and turning his back to the oncoming train, long before it reached him.
Mr Sayomporn and Mr Uthen have been suspended from duty. They have both denied the charges, police said.
The 56-year-old bus driver, Lapit Thongboon, was severely burned and remains in hospital.
