The train that derailed in northern Spain last Friday was found to have been travelling at 118 kilometres per hour, said the high court in Galicia on Tuesday.
The information came from the train’s black box which had been rescued from the scene of the crash.
The permitted speed on that stretch of track was only 30km/h.
The train came off the tracks and crashed into a pylon on its approach to the station at O Porriño, a small town in northwest Galicia.
The incident left four dead. The Portuguese driver was killed along with a US tourist and two Spaniards, the train’s conductor and another aged 23.
In addition, 49 people were treated for their injuries. Some remain still in hospital. None are reported to be in critical condition.
The high court revealed that “the train was going at 118 kilometres per hour when it derailed”.
"The driver received and acknowledged that he had received (by pressing a button) two L1 notices, which indicate the need to reduce speed," its statement read.
Routine maintenance being conducted in the area obliged the train to divert to another track where the speed limit was 30 km/h, O Porriño mayor Eva Garcia de la Torre said at the weekend.
The court, which is continuing its investigation, said it had yet to determine why the train was speeding.
Spain's Public Works Minister Rafael Catala called on Monday for the presidents of Renfe and Adif, which manages Spain's railway tracks, to appear before a parliamentary commission to ensure "transparency" in the accident inquiry.
The train is owned by Renfe, the Spanish rail company, but was on loan to Comboios de Portugal. It had departed from Vigo in Spain and was destined for Porto.
The court reported that the body of the Portuguese train driver would be repatriated after formal identification.
