Normally busy train stations across Belgium have been deserted due to a 24-hour strike by rail workers.
The network usually handles 500 thousand passengers a day. There have been reports of 350 kilometres of tailbacks on the country’s roads.
Eurostar services have also been affected.
Trains are running normally between London and Lille but passengers are then being taken on to Brussels by coach. High-speed links to Paris, Amsterdam and Cologne are also affected.
The dispute is over working conditions, particularly in the freight section.
The strike is due to end late on Monday evening, but there are warnings that services are likely to be slow to resume on Tuesday morning.