Work No. 8U(9)—U.K.A cut, forming an improvement of the Rainham Main Sewer, commencing in that watercourse at a point 15 metres north of the northern end of its existing culvert under the Tilbury Loop Railway, passing under that railway and the railway (Work No. 8) and terminating in that watercourse at a point 52 metres south of the southern end of that existing culvert;