London Transport announce that a contract worth nearly £1.2 million has been let for civil engineering work entailed in the realignment of the Circle and Metropolitan Lines and the Widened Lines between Moorgate and Aldersgate stations.
Source: wiktionary
To enable high-speed running to be maximised on the Western specifically, some signals were re-spaced, while track realignments at seven sites between Acton, Box Tunnel and Bristol Parkway enabled line speeds to be raised.