support of the bill. However the construction was managed by John Thompson, the engineer to the Don Navigation Company, until he died in 1795. The post was then held by Robert Whitworth until 1799, when he died also, and it is thought that one of Whitworth's sons acted as engineer until the finish of the work. The canal was opened as far as Elsecar by 1798 and fully opened by November 1804 at a cost of just under £100,000. The cost overrun was managed when the company obtained a second Act of Parliament on 30 May 1800, which allowed the original option for a £30,000 mortgage to be raised by shares, a mortgage of £10,000 to be obtained, and the toll rates to be increased. Construction costs included the provision of two reservoirs, at Elsecar and Worsbrough, tramroads from Elsecar basin to two ironworks and a colliery, which included inclined planes, and a tunnel near Swinton, which was built using the cut-and-cover method. The main line rose by through 19 locks. The canal was shut briefly in the summers of 1805 and 1806 due to a shortage of water, but was initially successful and by 1830 it was carrying 181,000 tons of coal a year. In the early 1820s, several proposals were made to build additional tramroads and reservoirs, but the plans were opposed by the Barnsley Canal and the Aire and Calder. Plans for an additional reservoir at Wentworth Castle, above the Worsbrough reservoir, were opposed in the House of Lords, unless the Company would release its exclusive rights to build tramways from the canal to local collieries, and the bill was withdrawn, rather than agree to a clause which would have broken their monopoly on the coal reserves near to the canal. A decision was taken instead to raise the level of the Worsbrough reservoir by , thereby increasing the surface area to , and this was completed in 1826. Railway competition The North Midland Railway, running from Leeds to Derby, opened in 1840 and this represented a major threat to the domination of the coal trade by all the South Yorkshire navigations. Parts of the railway ran alongside the canal. At Adwick upon Dearne the railway constructed a long cutting, and in order to maintain their alignment, the canal tunnel was demolished and the canal was re-routed to share the new cutting. The canal Company took the