The Barlow Train Shed – St Pancras Railway Station, Euston Road, London, England

Widely known for its Victorian architecture, St Pancras station stands between the British Library, King's Cross station and the Regent's Canal. It was opened in 1868 by the Midland Railway as the southern terminus of its main line which connected London with the East Midlands and Yorkshire. When it opened, the arched Barlow train shed was the largest single-span roof in the world. William Henry Barlow FRS FRSE FICE MIMechE (10 May 1812 – 12 November 1902) was an English civil engineer of the 19th century, particularly associated with railway engineering projects.

Between 1862 and 1869, Barlow was consultant engineer for the Midland Railway's southern extension from Bedford to London, including the layout of the London terminus station at St Pancras on Euston Road. To deal with the sloping site and the need to cross the Regent's Canal a short distance to the north, the platforms were constructed on a raised structure supported on cast iron columns and girders. Under this structure, a storage space was laid out for beer from the breweries at Burton upon Trent. With assistance from Rowland Mason Ordish, Barlow also designed the arched, cast iron station canopy which spans 240 feet (73 m) across the platforms without intermediate support – then the widest of its kind in the world. It was designed as a cost effective and efficient means of avoiding the need for additional solid structure in the lower level. George Gilbert Scott designed the hotel in front of the train shed.