thumb|Harry Bell Measures designed the surface buildings for the CLR, such as this one at Oxford Circus. The Central London Railway (CLR) was given permission in 1891 for a tube line between Shepherd's Bush and a station at Cornhill, and the following year an extension to Liverpool Street was authorised, with a station at Bank instead of at Cornhill. The line was built following the streets above rather than running underneath buildings, because purchase of wayleave under private properties would have been expensive. While the tracks in opposite directions mostly run side-by-side, in some places one line runs above another due to lack of space, with platforms at different levels at St Paul's, Chancery Lane and Notting Hill Gate stations. The tunnels were bored with the nominal diameter of , increased on curves, reduced to near to stations. The tunnels generally rise approaching a station, to aid braking, and fall when leaving, to aid acceleration. The Central London Railway was the first underground railway to have the station platforms illuminated electrically. All the platforms were lit by Crompton automatic electric arc lamps, and other station areas by incandescent lamps. Both the City and South London Railway and the Waterloo and City Railway were lit by gas lamps, primarily because the power stations for these lines had been designed with no spare capacity to power electric lighting. With the white glazed tiling, all underground Central London Railway platforms were very brightly lit. The use of electric lighting was further made possible because the Central London was also the first tube railway to use AC electrical distribution and the substation transformers, not compatible with DC, were able to reduce the voltage to the level required for lighting. Earlier tube lines used DC power generators at the 500 volts required to run the trains.
thumb|Harry Bell Measures designed the surface buildings for the CLR, such as this one at Oxford Circus. The Central London Railway (CLR) was given permission in 1891 for a tube line between Shepherd's Bush and a station at Cornhill, and the following year an extension to Liverpool Street was authorised, with a station at Bank instead of at Cornhill. The line was built following the streets above rather than running underneath buildings, because purchase of wayleave under private properties would have been expensive. While the tracks in opposite directions mostly run side-by-side, in some places one line runs above another due to lack of space, with platforms at different levels at St Paul's, Chancery Lane and Notting Hill Gate stations The tunnels were bored with the nominal diameter of , increased on curves, reduced to near to stations. The tunnels generally rise approaching a station, to aid braking, and fall when leaving, to aid acceleration. The Central London Railway was the first underground railway to have the station platforms illuminated electrically. All the platforms were lit by Crompton automatic electric arc lamps, and other station areas by incandescent lamps. Both the City and South London Railway and the Waterloo and City Railway were lit by gas lamps, primarily because the power stations for these lines had been designed with no spare capacity to power electric lighting. With the white glazed tiling, all underground Central London Railway platforms were very brightly lit. The use of electric lighting was further made possible because the Central London was also the first tube railway to use AC electrical distribution and the substation transformers not compatible with DC, were able to reduce the voltage to the level required for lighting. Earlier tube lines used DC power generators at the 500 volts required to run the trains.