Subway Construction.

The structure is carried on piles, spaced generally at about three-feet centres. The side walls are of mass concrete construction designed to retain the filling and overload on either side with the assistance of the roofslab. The roof-slab is of concrete-encased rolled steel joists, carrying ballast and sleepers, the continuity of the permanent way structure being uninterrupted.

The construction of the luggage subway is similar to the above except in the roofslab. Rail level over this subway is three feet below that at the passenger subway. In order to avoid deeper excavation in wet and unstable ground, the top of the 20ft slab was brought to rail level, and the rails carried through it.