Police in the southern province of Dong Nai on Monday arrested the driver of a barge and his assistant for running the vessel into a century-old rail bridge, causing a large section to fall into the river below.
The disaster on Sunday almost sent three motorbikes off the Ghenh Bridge, but no casualties were reported.
It however severed the major north-south rail link, spreading chaos across the nation's inadequate transport network.
Police confirmed pilot Tran Van Giang, 36, was arrested at around 7:15 a.m. along with Nguyen Van Le, 28, who assisted him, while the duo was hiding in the Mekong Delta province of Soc Trang.
The duo was then transferred to Dong Nai for investigation.
At around 11:35 a.m. on Sunday, Giang was driving the barge carrying 600 tons of sand up the Dong Nai River.
When the barge was passing under the Ghenh Bridge in Bien Hoa City, it struck a concrete pylon and sent two spans of the bridge, which is also used by motorbikes, into the water.
Three motorbike riders were rescued after their bikes almost fell off the bridge.
The barge capsized. Giang and Le managed to jump out and swam to safety before fleeing the scene.
The bridge collapse immediately paralyzed the traffic of the north-south rail service that connects Ho Chi Minh City and Hanoi. There is no alternative route.
On Sunday evening, all trains from the Saigon Railway Station were delayed indefinitely.
All southbound trains from Hanoi had to stop at Dong Nai’s Bien Hoa Railway Station and passengers were taken to HCMC by bus.
Meanwhile, passengers from the Saigon Railway Station were taken by bus to Dong Nai for their northward journey.
The situation caused messy scenes at both stations.
On Sunday evening, deputy transport minister Nguyen Hong Truong came to the crash site and ordered authorities to pull the broken spans of the bridge and the sunken barge out of the site.
He said the transport ministry would discuss to decide whether a new bridge would be built or the Ghenh Bridge would be fixed.
"It would take at least three months for the bridge to be fixed," he said.
He also ordered the Dong Nai authorities to quickly investigate the collision.
The 223-meter Ghenh Bridge across the Dong Nai River was built by the French in 1909. It has a track for trains in the middle with narrow lanes on both sides for motorbikes.
On February 6, 2011, a collision between a train and six cars occurred on the bridge, killing two and injuring 22 others.
On that day four employees of the state-owned Saigon Railways were in charge of regulating traffic on the bridge. However, they failed to prevent the cars from driving on the bridge even though the northbound train kept signaling its arrival.
Six cars, including a taxi, which had entered the bridge despite the railway staff's warning, were stuck on the bridge when the train approached.
In an attempt to clear the traffic congestion, a railway worker asked the taxi driver, who was near the end of the line of cars, to move.
However, the taxi driver refused and argued with the railway worker, instead.
By the time he moved, the train arrived and smashed into the other cars.
The Saigon Railways employees were then sentenced to between three years and five and half years for dereliction of duty.
Taxi driver Tran Minh Chau received a jail term of seven years for charges of "obstructing rail traffic."
After the fatal collision, the government ordered Dong Nai to build another bridge near the Ghenh Bridge for cars and motorbikes to travel on.
It was planned that the Ghenh Bridge would serve trains only.
In April 2013, the Buu Hoa Bridge opened to traffic, to both motorbike and cars.
Cars were not allowed to travel on the Ghenh Bridge, but Dong Nai authorities then secured the government's approval to allow one-way traffic for motorbikes only.