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The watercolour is inscribed on the reverse: This picture shows the building of Barlow's train-shed which was completed before Gilbert's famous hotel frontage was erected. The viewer is looking south, St Paul's Cathedral can be seen in the distance.
The picture shows the method of construction. Working from the pyramidal platform, carpenters built a heavy wooden rib-cage. The pre-fabricated cast-iron sections were slid into place over the rib-cage and rivetted together. The cage was the dismantled, and the canopy was left complete and free-standing.
St. Pancras trainshed was designed by William Henry Barlow and built by the Butterley Company between 1868-77. An original oval cast-iron plaque attached to one of the spines on the station platform states: Manufactured by the Butterly Company Derbyshire. 1868-77. The arch of the glass-and-iron train shed spans 240 feet and is over 100 feet high at its apex. This superb construction was an outstanding feat of Victorian engineering. When it was completed the massive roof, designed by William Henry Barlow, was the largest in the world. The roof is supported at ground-floor level by 690 cast-iron columns. This level was designed as a huge storage area for beer transported from Burton-on-Trent.