The Central Bureau of Investigation (CBI) said in a statement that they had arrested three Department of Railways officials on Friday.
The move follows the deaths of at least 275 people in a three-way crash involving two passenger trains and a freight train in eastern Odisha state on June 2.
The crash renewed questions over the safety of the massive and aging rail network in what is now the world’s most populous country and prompted a high-level inquiry to determine what caused it.
Initial investigations had suggested a traffic signaling failure may have occurred, though these can be due to either technical malfunctions or human error.
Various government figures have vowed to hold anyone found negligible to account.
“We can’t bring back those we have lost but the government is with them (families) in their grief,” said Indian Prime Minister Narenda Modi when he visited the scene of the disaster soon after it took place.
“This incident is very serious for the government … Whoever is found guilty will be punished severely,” he said.
The railways minister Ashwini Vaishnaw has previously said the accident had occurred “due to a change in electronic interlocking” and that an investigation would show “who was responsible” for that.
He has also previously claimed the cause and people responsible have been identified, though he stopped short of elaborating.
According to senior railway officials, the crash took place when the Coromandel Express, a high-speed train traveling from Kolkata to Chennai, was diverted onto a loop line and slammed into a heavy goods train idled at Bahanaga Bazar railway station.
Its carriages derailed onto the opposite track, where they were hit by an oncoming high speed train, the Howrah Express, which was traveling from Bangalore.
The situation was made worse by a combination of the high speeds – more than 120 kmph – at which both passenger trains were traveling and the heavy weight of the freight train, which was carrying iron ore, according to Jaya Varma Sinha, an Indian railways ministry official.
Odisha’s chief minister, Naveen Patnaik, has announced financial compensation for the families of those killed and injured.
The next of kin of the deceased will get 500,000 rupees ($6,067) while people suffering from serious injuries will be offered 100,000 rupees ($1,213).
India’s extensive rail network, one of the largest in the world, was built more than 160 years ago under British colonial rule. Today, it runs about 11,000 trains every day over 67,000 miles of tracks.
Upgrading India’s transportation infrastructure is a key priority for Modi in his push to create a $5 trillion economy by 2025. For the fiscal year that started in April, Modi’s government raised capital spending on airports, road and highway construction and other infrastructure projects to $122 billion, or 1.7% of its GDP.
