Eurostar has restarted a full service through the Channel Tunnel for the first time since a fire in 2008.
Repairs cost more than £60m and were completed on 10 February. Eurotunnel shuttle and freight trains have already returned to full capacity.
Eurostar said it had taken longer to return to full service because of the need for a new timetable.
A new direct service from Ashford to Brussels, delayed from December because of September's fire, has been launched.
Full Eurostar services resumed under the new timetable on Monday at 0525 GMT, when the first Paris-bound train left London.
The first direct service to Brussels departed from Ashford at 0627 GMT.
High-speed trains between London and Paris and Brussels are running through the tunnel at 100% capacity again, with a maximum of four per hour.
See layout of Channel Tunnel
A maximum of six freight trains, which run between Folkestone and Calais, can also run each hour.
The fire on 11 September broke out in a lorry on a freight train seven miles from France and took 16 hours to extinguish.
A total of 32 people on board had to be led to safety, with 14 suffering minor injuries.
A section of the tunnel known as Interval 6 was damaged, causing all services to stop for two days before one of the two tunnels was reopened.
The Channel Tunnel has suffered several incidents since it opened to traffic in 1994, although only one - a fire in 1996 - caused major injuries.
That fire caused £200m worth of damage and burned for more than five hours, wrecking the concrete lining and facilities over about half a mile of tunnel.
In August 2006, 34 people had to be led to safety after a fire broke out on a lorry being carried on a freight train. THE BBC