Thousands of people have been trapped for up to 24 hours on trains suffering electrical problems in France, with some services running low on food, drinks and toilet roll.
Several people had to be evacuated for medical reasons, according to broadcaster France-Info.
Others posted images of children sleeping on floors and described having to deal with electricity shut-offs and crowded train platforms.
National rail authority SNCF said problems on multiple routes began on Saturday afternoon, including a "major electrical supply failure" that halted traffic in southwestern France and disrupted travel from there to Paris.
Four high-speed trains connecting Bordeaux with nearby cities were stranded on tracks into the night, SNCF said.
Passengers on these trains were taken back to where they had departed from overnight and on Monday morning, then put on buses and other trains to reach their destinations.
Florence de Silva wrote on Twitter that by 11.40am on Monday, nearly 500 people were stranded at the town of Hendaye, waiting for a bus to Bordeaux.
Some people travelling to Paris were still stuck on trains by late Monday morning.
There are expected to be delays until Tuesday morning, junior minister for transport
Jean-Baptiste Djebbari told BFM television.
Many passengers expressed their anger on social media, with some providing regular updates about their journey.
Jade Grandin said she spent 13 hours on a train from Pau to Paris - a trip which should have taken between four and five hours.
She said she had little to eat and that the train had run out of toilet roll.
Another passenger, Pierre, said it had taken nearly 24 hours to reach Paris from Bayonne.
At one point, the electricity had cut out on the train and passengers were ordered to leave their carriages in complete darkness, he said.
He also said the bar had run out of food, there was no more soap, and there were no seats in between passengers to allow for social distancing.
"Some people aren't feeling alright, it is going crazy," he wrote on Twitter.
SNCF will reimburse all passengers three times the cost of their tickets and is distributing 4,000 masks, water and food, the junior transport minister said.
Mr Djebbari said 37 miles of track had suffered damage to high-power overhead cables.
According to an estimate from SNCF, around 5,000 travellers were affected by delays or train cancellation