The Bakerloo line opened in 1906 as the Baker Street and Waterloo Railway.
Its original name described the two termini connected by the first section of the route. The line opened between Baker Street and Lambeth North, with Waterloo also served in its initial development. The shortened name “Bakerloo” soon became widely used and eventually became official.
The route was built as a deep-level tube railway and later expanded northward and southward. It eventually reached stations including Paddington, Queen’s Park and Harrow & Wealdstone, giving it a much larger role than its original central-London section.
The line’s name is a blend of “Baker Street” and “Waterloo.” This type of nickname was common in London, but the Bakerloo name became one of the network’s permanent line names.