It was not quite the day without trains or rail workers the unions had called for but, after falling to below 15 percent last Wednesday, the number of strikers rose again to 27.58 percent, roughly the same as on the first day, 3 April.
Among the network's key workers, 74.4 percent of drivers stopped work, 74.3 percent of inspectors and 36.7 percent of signal operators.
The strike is organised on a rolling programme of two-day stoppages, with the next due on Friday and Saturday.
As the company had announced the previous day, two-thirds of TGV high-speed trains were cancelled with disruption of regional and local services.
A strike over working conditions on some regional transport lines added to commuters' problems in the Paris region.
An exceptionally high number of traffic jams caused tailbacks on 530 kilometres of road in Ile de France at 9.15am.
'Sabotage' and demos
The rail service between Paris and Normandy stopped completely on Monday morning due to an overhead cable being cut.
The SNCF rail company's management said they suspected sabotage and would file a legal complaint.
Normal service was resumed at 10.15am.
A cable was also cut or broke in the south of France, adding to the turmoil at Marseille's mainline station, where more than 10,000 passengers were briefly stranded when strikers swarmed onto the tracks.
Strikers in the Mediterranean city also marched to the Old Port and to the local university in a show of solidarity with students occupying buildings in protest at the government's plan to tighten entry to higher education.
Railworkers demonstrating at boss's holiday home, Left-wing local councillor tweets
Place Beaurivage tous ensemble avec les cheminots ! #Biarritz aujourd'hui chez Pepy ! Quelle belle lutte ✊ ! ???? % des cheminots en grève aujourd'hui #14Mai #SNCF#JeSoutiensLaLutteDesCheminotsSANDRA PEREIRA OSTANEL (@SPereira64600) 14 mai 2018
CGT Fédération des Services publics @cgtcheminots pic.twitter.com/4xRmlTJ5Ih
In the south-western city of Bayonne strikers took their protest to the holiday home of their boss, Guillaume Pépy, while in the Channel port of Caen they staged a demonstration outside the office of local MP Fabrice Le Vigoureux, a member of President Emmanuel Macron's France on the Move (REM) party, local media reported.
The unions, who say they are defending a public service as well as their own working conditions, claim Monday's turnout is a response to Pépy's claim that the majority of SNCF employees support the reform and have organised a ballot in an effort to show that is not true.
An early vote in the southern city of Nice saw 95 percent against with 63 percent of the 718 employees taking part.
They also accused Pépy of preparing to privatise the company after Le Parisien newspaper published the minutes of a working group that appeared to show managers lobbying for shares in subsidiaries to be made available for public offer.
The chair of the committee that prepared the reform bill, REM MP Jean-Baptiste Djabbari dismissed the suspicions as "fantasy" but said that the principal of "non-transferability" would be inscribed in the law "to reassure everybody".
On European Commission orders, however, the network will be opened up to competition in 2021, leaving private operators free to run trains on the network, even if the SNCF remains public, as the government has promised.