Editing Waterloo & City line (section)

====Construction====
Following royal assent, the company prepared for construction. The new company issued its prospectus in March 1894 and the subscription list closed on 21 April; 54,000 shares at £10 each were offered and there was a slight over-subscription. A dividend of 3% per annum payable out of capital was promised during the construction phase.{{sfnp|Gillham|2001}}

Tenders were acquired for the main tunnel work, and a contract was awarded to [[Mowlem|John Mowlem & Co]] for the sum of £229,064{{sfnp|Gillham|2001}} ({{Inflation|UK|229064|1894|r=-4|fmt=eq|cursign=£}}).{{Inflation-fn|UK|df=y}} The consulting engineers were [[W. R. Galbraith]] (of the LSWR) and [[James Henry Greathead|J. H. Greathead]], developer of the [[tunnelling shield]]. The resident engineer was H. H. Dalrymple-Hay. Mowlems' engineer in charge was William Rowell.<ref name = engineer>''The Engineer'' (periodical), 26 July 1895</ref>

Mowlem began work on 18 June 1894, first building staging in the river about {{convert|500|ft}} west of Blackfriars Bridge. Piles were driven for a [[cofferdam]] and two vertical shafts of {{convert|16|ft}} internal diameter were constructed as headings for the tunnel drive. The average depth of the tunnels is about {{convert|45|ft}}, with its deepest points at the River Thames, at {{convert|63|ft}} underground.

Driving the running tunnels started in November 1894, using the [[James Henry Greathead|Greathead]] system of shield excavation, cast iron segment lining, compressed air working, and compressed air grouting behind the tunnel lining. Twenty men worked in each heading.<ref name = engineer2>''The Engineer'' (periodical), 2 August 1895</ref>

[[File:W&C muck away.jpg|thumb|Removal of spoil in tunnelling the Waterloo & City Railway]]

The excavated material was removed from the staging near [[Blackfriars Bridge]]; it was conveyed there from the shields by a narrow gauge railway using electric locomotives supplied by the [[Siemens|Siemens Company]]. Two were in use and a third was on order at August 1895. They operated on {{convert|18|in|adj=on}} gauge track with a twin overhead trolley wire (i.e., not using the track for current return) at {{val|200|u=V|s=&nbsp;DC}}.<ref name = engineer2/>

The station works at Waterloo were constructed by Perry and Co. The station tracks run in separate but adjacent arches supporting the main line station, which run transversely to the main line track. The arch piers needed to be underpinned to about {{convert|8|ft}} lower than the original foundations.{{sfnp|Gillham|2001}}