Work No. 18A—A railway (3,476 metres in length) commencing by a junction with the railway (Work No. 17) at its termination, passing eastwards under Sandling Road (Work No. 18H) on the northern side of the Ashford and Folkestone Railway and the northern side of the Dollands Moor Freight Yard, then under the roundabout (part of Work No. 18J) and terminating at a point on the western side of the M20 at Newington 215 metres south-west of the junction of Newington Road with the A20;