(Bloomberg) -- India said its deadliest rail accident in nearly three decades was due to a fault in an electronic signaling system, as the focus turned from recovering victims to restoring train operations.

A high-level inquiry into the three-train collision is underway, and Railways Minister Ashwini Vaishnaw said a preliminary investigation showed the accident on Friday evening happened “due to a change in electronic interlocking.” 

“Who has done it and what is the reason will come out of after an investigation,” he told news agency ANI. 

A search for survivors has ended, with at least 288 fatalities, and more than 800 passengers injured. Hydraulic excavation machines and cranes are being used to clear the mangled wreckage, and over 1,000 workers are involved to expedite restoration efforts, Indian Railways said in a statement Sunday. 

Currently the focus is on restoration, Vaishnaw said on Sunday. He visited the accident site in the state of Odisha and said the target is to restore all damaged tracks by Wednesday morning. Victims have all been retrieved, he said. 

An express passenger train collided with a stationary goods train after entering into a loop line from its original path, resulting in carriages derailing and ending up on an adjoining track. Another express passenger train from an opposite direction moving at high speed then rammed into the coaches and was also derailed. 

Photos and videos from the site showed overturned carriages piled on top of others, with several upturned and more littered across tracks. Among the wreckage were disfigured and burnt bodies and dismembered human body parts, and scattered passenger belongings. 

India’s rail network, one of the largest in the world, carries hundreds of millions of passengers each month but also suffers from scores of accidents. Most are blamed on outdated signaling equipment or human error. About 3,000 people have been killed in train accidents since 2000. In 1995, more than 300 people died in a collision between two trains near the northern town of Agra. 

Prime Minister Narendra Modi visited the accident site and a nearby hospital on Saturday, and reviewed rescue and relief efforts. He pledged medical help to those injured, and expressed condolences to families of those who died.

Investigators were looking into causes behind the accident including human error, signal failure, or sabotage. A signal was given to Coromandel Express to enter the main line but it was taken off and the train entered the loop line and crashed into the goods train parked there, Press Trust of India reported, citing a preliminary report of the investigation.

(Updates with preliminary cause in first paragraph)

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