The Eurotunnel train, carrying 382 people, stopped about a quarter of its way from Folkstone, England, to Coquelles, France, and passengers were removed to an adjacent, parallel service tunnel for evacuation. There were no injuries reported.
Eurotunnel blamed the issue on a power fault in the tunnel's overhead power lines, and added service was expected to resume normally by Tuesday.
"All of a sudden I heard this crashing noise, it didn't sound like the train itself had crashed but what became evident later on was that the power cables had got entangled or come down. For about 20 minutes the train just stopped and we didn't know what had happened," passenger Richard Byrom told BBC Radio.
Delays Monday could affect the Tour de France bicycle race, whose teams ended a stage of the race in London and are traveling to France.