work to build HS2. Another was built in 1839 at Derby, England by the North Midland Railway. A guidebook of the time says: This roundhouse narrowly escaped demolition when the works closed down, and was classified as a listed building. It was restored in 2010, being converted into a brand new site for Derby College, with a new addition called the 'Stephenson Building' including the other survival of demolition - the original Midland Counties Railway workshop. The new site was opened in September 2009. Tours can be arranged through Derby Tourist Information Centre. In Leeds, Thomas Grainger designed the roundhouse near Armley Gyratory that was opened in 1847, with accommodation for 20 trains from the Leeds & Thirsk Railway. It was operational until 1904. The Fenton, Murray and Jackson building in Leeds (1831–1843), a private workshop, may previously have been laid out in a radial pattern like a roundhouse. The Roundhouse, Chalk Farm, London was built in 1847, but was too small for its function within 20 years (it is now an arts centre and concert venue). Barrow Hill Engine Shed, which is home to a number of preserved locomotives is still in use. United States It is estimated that there were about 3,000 roundhouse sites in the United States, although at least three times that number were built between 1840 and 1950, since many were torn down and rebuilt as locomotives became increasingly larger. Although the United Kingdom was home to the earliest roundhouse (1837), the US was not far behind, with several being built around 1840 for the earliest railroads. It is likely that the first in the US was built by the Baltimore and Ohio at Mt. Clare (Baltimore), although this cannot be confirmed because early records have been lost. Early roundhouses, especially those built in cold climates, were fully enclosed with the turntable under cover as well as the stalls. Once locomotives became too large to fit in these structures, they were torn down and replaced with "donut" shaped structures that surrounded an open turntable. Although some roundhouses used by Class 1 railroads were built as a full-circle with as many as 52 stalls, the vast majority were only part of a circle with 12 or fewer stalls. Nearly every locomotive terminal in the country was anchored by a roundhouse, especially if a railroad owned more than a few locomotives. The largest concentration of roundhouses was