absorbed by Allied Ironfounders Limited in 1929. This was in turn taken over by Glynwed which has since become Aga Foodservice. The Coalbrookdale foundry closed in November 2017. Several of Coalbrookdale's industrial heritage sites are to be found on the local trail: including: Coalbrookdale railway station, the Quaker Burial Ground, the Darby Houses, Tea Kettle Row and the Great Western Railway Viaduct. Museum In the century after the Old Blast Furnace closed, it became buried. There was a proposal for the site to be cleared and the furnace dismantled, but instead, it was decided to excavate and preserve it. It and a small museum were opened to celebrate 250 years of the Company in 1959. This became part of a larger project, the Ironbridge Gorge Museums. Its Museum of Iron is based in the Great Warehouse constructed in 1838 and Ironbridge Institute is based in the Long Warehouse, these two form the sides of an open space. On another side of which is the Old Blast Furnace, now under a building (erected in 1981) to protect it from the weather. The fourth side is a viaduct carrying the railway that delivers coal to the Ironbridge Power Station. One of the two tracks is due to be taken over by Telford Steam Railway as part of its southern extension from Horsehay. The Museum's archaeology unit continues to investigate the earlier history of Coalbrookdale, and has recently excavated the remains of the 17th century cementation furnaces, near the site of the Upper (formerly Middle) Forge. Old Furnace The Old Furnace began life as a typical blast furnace, but went over to coke in 1709. Abraham Darby I used it to cast pots, kettles and other goods. His grandson Abraham Darby III smelted the iron here for the first Ironbridge, the world's first iron bridge. The lintels of the furnace bear dated inscriptions. The uppermost reads "Abraham Darby 1777", probably recording its enlargement for casting the Iron Bridge. It is unclear whether the date on one of the lower ones should be 1638 (as it is now painted) or 1658 (as shown on an old photo). The interior profile of the furnace is typical of its period, bulging around the middle, below which the boshes taper in again so that the charge descends into a narrower and hotter hearth, where the iron was molten. When Abraham Darby III enlarged the furnace, he only