Massive Arson Attack: Rail network hit before Paris Olympics opening.

Paris Station Delays: Major delays affect 800,000 people.

SCNF Statement: Attacks aimed to damage installations.

Fire Timing: Fires began at 4 a.m.

Authorities' Response: Not labeled terror attack; severe disruptions.

Transport Minister's Condemnation: Minister condemns attacks; warns of travel disruption.

Targeted High-Speed Lines: High-speed rail lines were main targets.

Coordinated Acts: Fires on multiple lines; one stopped.

Repair Timeframe: Repairs will take all weekend.

Eurostar Advisory: Passengers advised to postpone trips.

Olympics Impact: Attacks hours before Olympics opening.

Developing Story: Further updates expected.