Christmas Under the Sea

The Channel Tunnel linking Calais and Folkestone is one of the longest in the world, with 38 of its 50 kilometres lying beneath the English Channel. Christmas 2007: a special supply train – a kind of rolling workshop – begins its journey to bring all the equipment needed by on-site technicians to replace a switch in the tunnel more than 40 metres under the sea and 17 kilometres from its entrance. As planned, the men dismantle the switch into smaller parts. After clearance using an excavator, high-pressure cleaners remove a tough build-up of oily grime – deposited over many years of rail service – on the surface of the concrete. But the new Vossloh switch, weighing in at 130 tonnes, is already on its way. This is the moment the engineers will see whether their calculations are correct – and heave a sigh of relief! The switch fits perfectly in its bed. With the switch in place, it’s time to straighten out any kinks in the track. Over to the surveyors. Bit by bit, the switch is aligned – a millimetre at a time. Finally, the control cables of the Channel Tunnel are re-connected and full control reverts to the control centre up at Calais – after only seven hours of switch replacement work. The busy tunnel schedule only rarely permits service interruptions of this kind – and Christmas is one. Only minutes later, the next Eurostar was again speeding down the track at 160 km/h.