Vinci and Bouygues Construction are claiming a world first with their plan to adapt an earth pressure balance TBM  to operate as a slurry pressure balance machine to build the Euro 264M Cairo metro Line 3 extension between Haroun and El Nozha stations. The new phase of works (Phase 4A) continues on from Phase 2, which was brought into service in May 2014 more than six months ahead of schedule. Phase 4A consists of 5.15 km of tunnel and five underground stations on Line 3, the east-west link across the Egyptian capital. The joint venture has committed to a very short design-build delivery deadline of 34 months based on the experience it has acquired over more than 30 years of working on the metro project, the oldest in Africa, and to the TBM technical innovation. The TBM which will be converted is named Imhotep and was working on phase 4.