Channel Tunnel 2G and 3G services. Both EE and Vodafone planned to offer LTE services on the route; EE said it expected to cover the route with LTE connectivity by summer 2014. EE and Vodafone will offer Channel Tunnel network coverage for travellers from the UK to France. Eurotunnel said it also held talks with Three UK but has yet to reach an agreement with the operator. In May 2014, Eurotunnel announced that they had installed equipment from Alcatel-Lucent to cover Running Tunnel North and simultaneously to provide mobile service (GSM 900/1800 MHz and UMTS 2100 MHz) by EE, O and Vodafone.
Channel Tunnel techniques from the oil industry were employed. Tunnelling was a major engineering challenge, with the only precedent being the undersea Seikan Tunnel in Japan, which opened in 1988. A serious risk with underwater tunnels is major water inflow due to the pressure from the sea above, under weak ground conditions. The tunnel also had the challenge of time: being privately funded, early financial return was paramount. The objective was to construct two rail tunnels, apart, in length; a service tunnel between the two main ones; pairs of cross-passages linking the rail tunnels to the service one at spacing; piston relief