In 1898, the Admiralty Tunnel drove through the entire width of the Rock (1,053 yards) in an east-west direction to reach Sandy Bay and the various quarries situated on the east side. A railway system similar to that employed at Camp Bay connected the Dockyard through the tunnel and round via Catalan Bay and the base of the North Front to Waterport and along the Queensway all the way to the Dockyard thus completing the circuit.
Not all the stone was obtained locally. The bulk of the limestone ashlar, for quay walls, docks and buildings, was obtained ready dressed from Spain, being brought by railway to the town of Algeciras and then transported by boat across the Bay of Gibraltar to the works. Granite used to floor the docks and to construct copings and landings steps were mostly imported from Cornwall.