branch under an Act of Parliament obtained in 1944. The last heavy commercial traffic was the transfer of coal from Endon to Cheddleton, which ceased in 1952. Johnson Brothers built three new, specialized barges, Milton Maid, built in 1967, Milton Queen in 1973, and Milton Princess in 1978, to convey pottery over a stretch of the canal from its factory in Milton to a new packaging plant near the Ivy House lift bridge in Hanley. The experiment was a success: transport by water reduced costs by 50 per cent and diminished the number of breakages of wares. Operation continued until 1990, becoming one of the last commercial narrowboat runs. Operation Because the Caldon Canal was promoted and built by the proprietors of the Trent & Mersey Canal Company, as such it is more properly called the Caldon Branch of that canal. It was built to carry limestone from Caldon Low Quarries which was transported to Froghall wharf via three inclined tramways. Other important traffic for the canal was coal from the Cheadle Coalfield and ironstone from the several iron ore mines in the Churnet valley and Kingsley area. The canal was subject to considerable mining subsidence in the Etruria area, which eventually led to the need for an entirely new lock, Planet Lock, with a rise of just , to adjust the levels. Water to the canal is supplied by three reservoirs and the River Churnet. Stanley reservoir holds 22 million cubic feet (670 Megalitres (Ml)), and joins the canal just below Endon basin, while Knypersley holds 41 million cubic feet (1,200 Ml) and joins the canal above Engine Lock. The final section of its feeder was originally the Norton Green branch, a private canal built at the same time as the main line, to service a colliery. Rudyard reservoir holds 122 million cubic feet (3,500 Ml), and its feeder, which joins the Leek branch near the Churnet aqueduct, follows much of the proposed route of the Macclesfield Canal extension to Leek. Since the Caldon joins the summit level of the Trent and Mersey system, it is still a valuable supply for that canal too. Restoration Although the canal was never legally closed, its traffic had declined to such an extent that by the 1960s it was almost unusable. A survey of it was carried out in 1960 by the Inland Waterway Protection Society, which had been formed in 1958