PARIS: Tens of thousands of rail passengers struggled through a second day of cancelled trains Saturday as investigators tracked saboteurs who paralysed the network just ahead of the Paris Olympics opening ceremony.

The SNCF rail company chief Jean-Pierre Farandou said services would be back to normal by Monday. But deputy transport minister Patrice Vergriete acknowledged that 160,000 of the 800,000 people due to travel this weekend still faced cancellations.

Nearly one third of trains were cancelled in northern, western and eastern France. About a quarter of Eurostar high speed trains between Paris and London and Paris and Brussels were also called off.

No claim of responsibility has been made for the meticulously planned night-time attacks on cabling boxes at junctions north, southwest and east of the French capital, just ahead of Friday’s Olympics opening ceremony in Paris. Maintenance workers thwarted a fourth attack.

But Interior Minister Gerald Darmanin said the investigation was progressing.

“We have uncovered a certain number of elements that allow us to think that we will soon know who is responsible for what clearly did not sabotage the Olympic Games but did sabotage part of the holidays of the French people,” Darmanin told France 2 television.

French authorities are on high alert for a terrorist attack during the Games, which run through August 11. Tens of thousands of police and troops are on Olympics security duties.

Some 250,000 people missed their train on Friday, according to SNCF, because of the attacks that dozens of investigators are now working on.

About three out of every 10 trains were cancelled Saturday in the three regions affected by the attacks, with most trains still operating delayed by between one and two hours, SNCF said.

Bruno Cevalier and Pauline Favard tried to get from Bordeaux in the west to the northern city of Lille for an Olympics basketball game.