"A train has malfunctioned in the tunnel, and we are currently transferring passengers to another shuttle via the service tunnel, which will return them to our Folkestone terminal," Eurotunnel communicated via Twitter late Tuesday UK time. "We sincerely apologize for the trouble caused."
Eurotunnel Le Shuttle operates trains designed to transport both passengers and freight vehicles through an underwater tunnel connecting England and France.
This mechanical failure impacted the 3:50 p.m. local time service departing from Calais, France, and bound for Folkestone, England. The train was carrying hundreds of passengers, along with a number of dogs, as reported by PA Media news agency.
Passenger Michael Harrison shared his unsettling experience with PA.
"We boarded the 3:50 p.m. crossing, and approximately 10 minutes into the journey, the lights went out and the train came to a halt. We were informed that they needed to examine a potential problem with the wheels," he explained.
"They spent about an hour and a half investigating, but evidently couldn't identify any issues. They reset some systems and we started moving again for another five minutes," Harrison continued. "Then it happened again, and we waited another couple of hours before they decided that although they couldn't pinpoint a problem, they had to evacuate us to another train."
Passengers were then led through the emergency link tunnel to the service tunnel, where they walked for about 10 minutes until they reached a different train, Harrison told PA.
Additional problems with the replacement train resulted in passengers finally arriving in the UK six hours after their initial departure, he added.
Typically, the Eurotunnel Le Shuttle service takes just 35 minutes to complete the journey between Folkestone and Calais.
Another passenger informed PA that "several people were quite anxious about being in the service tunnel; it's a rather strange environment. We were stuck down there for at least five hours."
Fellow passenger Kate Scott mentioned that the temperature within the tunnel was a concern.
"It was hot, there was no air conditioning, and although they distributed water, we were largely unaware of what was happening," she said.
Sarah Fellows, 37, described her experience to PA, stating that "the service tunnel was frightening."
"It felt like a scene from a disaster film. We were essentially walking into the unknown, with no clear understanding of the situation. We all had to remain under the sea in this long queue," she recounted.
"There was a woman crying in the tunnel, and another woman traveling alone had a panic attack," Fellows added. "They seemed to expect elderly individuals to walk for a mile through the middle of an underwater tunnel."
"I felt panicked at one point, and Border Force personnel told us that the tunnel had only been evacuated once before in the past 17 years," she said.
This incident also caused disruptions to subsequent services.
"Because of the earlier train malfunction, we recommend that you do not travel to the terminal tonight," Eurotunnel advised in a separate tweet late Tuesday. "Please plan to arrive after 6 a.m. tomorrow."
On Wednesday morning, the company confirmed that train services had resumed. "Following yesterday's incident, we have now returned to our normal operating schedule," they tweeted.
The Channel Tunnel significantly transformed travel between the UK and mainland Europe when it opened in May 1994, offering a much faster alternative to ferry routes.
The concept had been discussed for over 180 years before British and French workers finally commenced construction in 1988, digging towards each other from opposite sides of the Channel.
It took 13,000 workers six years to construct the 31.4-mile tunnel, with 23.5 miles running underwater, making it the longest undersea tunnel in the world.
