The only passenger rail link between Britain and the rest of Europe has been shut down indefinitely, Eurostar said Sunday. Services have been suspended since late Friday, when a series of glitches stranded five trains inside the Channel Tunnel and trapped more than 2,000 passengers for hours. More than 55,000 passengers overall have been affected. Some passengers stayed underground for more than 15 hours without food or water, or any clear idea of what was going on - prompting outrage from travelers and a promise from Eurostar that no passenger train would enter the tunnel until the issue had been identified and fixed. Eurostar official Nick Mercer said three test trains sent through the Channel Tunnel Sunday ran successfully, but that it became clear that the especially bad weather meant that snow was being sucked into the trains in a way “that has never happened before.” “The engineers on board have recommended strongly that, in light of further snowfalls that are happening tonight, we make some modifications to the trains to stop snow being ingested into the power car,” he told the BBC. A Eurostar statement said the fleet was already undergoing upgrades and that more tests were planned for Monday. But a spokeswoman said she could not guarantee that service would resume Tuesday. A statement posted to the company's website urged passengers to delay their trips or seek refunds.