Central line (London Underground) interchange, it was ruled out on grounds of cost, the disruption it would cause to the Central line while being built and because the platforms would be too close to sidings at Liverpool Street and would not be developed until after Crossrail is fully operational. The developers of the "First Central" business park at Park Royal, west London, were planning a new station between North Acton and Hanger Lane. This would have served the business park and provided a walking distance interchange with Park Royal station on the Piccadilly line. This is not being actively pursued; London Underground has said
London Underground cells". The Waterloo and City Railway opened in 1898, followed by the Central London Railway in 1900, known as the "twopenny tube". These two ran electric trains in circular tunnels having diameters between and , whereas the Great Northern and City Railway, which opened in 1904, was built to take main line trains from Finsbury Park to a Moorgate terminus in the City and had diameter tunnels. While steam locomotives were in use on the Underground there were contrasting health reports. There were many instances of passengers collapsing whilst travelling, due to heat and pollution, leading for calls to clean