Extreme weather conditions in northern France caused five trains to malfunction inside the tunnel that evening. A "unique" fine and dry snow is believed to have penetrated the power cars' door screens and seals before melting in the tunnel's 25oC environment and interfering with the trains' electrics.
Problems escalated while the 19.37 Eurostar service from Disneyland, the first failure, was removed from the tunnel by special Eurotunnel diesel locomotives. With only one line through the tunnel in operation, snow collected on the roofs of four subsequent trains while they were held open to the elements at Calais. They also broke down shortly after entering the tunnel.
Described by both Eurostar and Eurotunnel as an "unprecedented event in the 15 years of Channel Tunnel rail services," 1364 passengers on two of the incapacitated trains were eventually evacuated through the service tunnel. Thousands more passengers were left waiting at London St Pancras, Brussels and Paris as 146 Channel Tunnel train services, capable of carrying 700 passengers each, were suspended over the next three days (December 19-21).
After the trains were tested to ensure their suitability to run, limited operations were instituted between December 20 and December 24. No new tickets were issued, and many travellers were advised to stay away as Eurostar attempted to clear the backlog of frustrated passengers hoping to complete their journeys in time for Christmas.
Many questions still remain unanswered about exactly what happened that evening and why, and whether the response of Eurostar staff to the breakdowns, which has been publicly criticised by Eurotunnel officials, was appropriate.
With a report on the incident from an independent inquiry, headed by former Eurotunnel commercial director and GNER chief executive Mr Christopher Garnett, expected to be published by the end of January, Mr Richard Holligan, senior press officer for Eurostar communications, declined to comment on accusations from Eurotunnel that the response of train staff was inadequate and that safety rules were ignored.
Holligan did, however, admit that the train's winterisation system failed and that modifications have since been made to prevent similar breakdowns in the future. He also defended Eurostar's response to the situation and the treatment of the stranded passengers. The company announced on January 19 that it would pay up to £10 million in compensation to around 100,000 passengers caught up in the fiasco, including a full refund, additional free journey, £150 in cash and any reasonable expenses.
"While the disruption was ongoing, passengers without a place to stay who were away from home were able to claim for a three-star hotel and reasonable out of pocket expenses," Holligan says. "We ensured we took care of our most vulnerable passengers and repatriated 7200 using chartered coaches and ferries. We were consistent in our message throughout the disruption - that if people did not have to travel they should not, and that they would receive an exchange or refund of their tickets."
While Eurostar oversaw the handling of passengers during the incident, Eurotunnel, as the tunnel operator, was responsible for the technical aspects of the incident. It presided over the rescue operation, including the removal of each of the Eurostar trains, and worked closely with emergency services personnel who led the passenger evacuation process.
Mr John Keefe, a spokesperson for Eurotunnel, said that it took longer than expected to implement the emergency evacuation procedure because the five trains broke down almost simultaneously with each having to be removed one at a time.
However, he dismissed claims made in some media outlets that people were stuck in the tunnel for 15 hours as "rubbish" saying that such estimates of time might only be contrived from overall delays of the trains travelling between Paris and London.
Keefe says that an evacuation is only considered "when conditions on the train are no longer sustainable for passengers," and that every effort was made to restore power on the trains before passengers were removed.
"On the second Eurostar that broke down at 21.40 GMT those passengers were only stopped in the tunnel for around an hour and a half before the evacuation process began. The driver initially tried to repair the train with the technical procedures on board. When they then lost power just after 23.00 GMT, the driver requested evacuation at that stage."
Keefe says that it took approximately 30-60 minutes for the emergency evacuation procedure to be completed because only two doors were used to exit the train. He was though critical of Eurostar staff who allowed passengers on one of the trains to take their luggage with them during the evacuation. This he says inevitably delayed the process and caused further confusion at Folkestone when a bag check was undertaken by police as passengers were transferred to an unstaffed Eurostar train to complete their journey to St Pancras.
"We were supposed to evacuate people, not suitcases," Keefe says. "There were 640 people on that train all situated in a confined space. The consequences of that were increases in the amount of time it took people to get off the train. The last thing we wanted was for cross passengers to be held up as people carried their luggage up and down stairs, which can be enormously difficult."
Keefe says that Eurotunnel has cooperated fully with the inquiry, including holding regular meetings with Garnett and, like Eurostar, submitted a log of the evening's events, including all the information about the breakdown of the trains and the response of staff. As the operator awaits details of the inquiry's findings, he says that Eurotunnel hopes any recommendations made will prevent a similar incident in the future.
"It is in everyone's interests to find out what happened and why Eurostar trains broke down to prevent this from happening again," Keefe says. "Eurostar is our biggest customer so it is not in our interest for them to be unable to provide an adequate service for passengers."