Work No. 12A—U.K.A railway (2,520 metres in length) on the northern side of the railway (Work No. 12) commencing by a junction with that railway at a point 50 metres east of its commencement, passing eastwards under Henhurst Road (Work No. 12D) and terminating by a junction with Work No. 12 at a point 515 metres east of the intended bridge carrying that road over that railway;