Loosely secured trailer likely caused Danish train accident Danish authorities say a deadly accident which saw a high-speed passenger train strike a semi-trailer that fell off a freight train coming from the opposite direction, "very likely" happened because the unit "wasn't properly secured."

COPENHAGEN, Denmark -- Danish authorities said Thursday a deadly accident which saw a high-speed passenger train strike a semi-trailer that fell off a freight train coming from the opposite direction, "very likely" happened because the unit "wasn't properly secured."

The Accident Investigation Board, known by its acronym AIB, said in a preliminary report that "local wind conditions could have had enough strength" to knock the semi-trailer off the freight train's flatcar as it crossed the Storebaelt system of bridges and a tunnel that link the central Danish islands of Zealand and Funen

Eight people were killed and 16 injured in the Jan. 2 accident on a bridge during strong winds. The victims were all on the passenger train.

The freight train involved in Denmark's deadliest train accident in 30 years was transporting semi-trailers filled with beer crates when it smashed into the high-speed passenger train and ripped open its left side.

The AIB said "observations of sparks" along the freight train before the accident, the location of the trailer after the crash and the investigation of the lock system made them conclude it wasn't securely attached.

It also found two other trailers on the same freight train that weren't properly locked.

At the time of the accident, the 18-kilometer (11.2-mile) Storebaelt link was closed to road traffic because of high winds but trains could still go across.

Days after the accident, Denmark temporarily banned truck trailers on trains after an AIB test had shown some semi-trailers were not securely locked on the flatcars of freight trains.

On Jan. 8, the Danish Transport, Construction and Housing Authority also imposed stricter conditions for freight transport over the Storebaelt rail link "under special weather conditions" and banned the crossing of freight trains during storms.