Birmingham Interchange station will be on the outskirts of Solihull, close to the strategic road network including the M42, M6, M6 toll and A45, all crossed on viaducts; also close to Birmingham Airport and the National Exhibition Centre. North of the station, a triangular junction west of Coleshill will link the HS2 Birmingham city centre spur with the line continuing north, from which Phase 2a and 2b will be developed. The northern limit for Phase 1 will be a connection onto the WCML near Lichfield. This part of the line would be operative with compatible high-speed trains moving onto the conventional track WCML while the western leg of Phase 2 is being built. The city centre spur will be routed along the Water Orton rail corridor, the Birmingham to Derby line through Castle Bromwich and in a tunnel past Bromford.