As the populations of Newcastle and Gateshead continued to grow, more water was needed, and a second reservoir was constructed at Hallington, known as the West Reservoir. Land was purchased in 1880, and work started in 1884, using direct labour under the supervision of John Forster, the resident engineer. Despite appalling weather in the winters of 1886 and 1887, and a poor understanding of soil mechanics which affected the construction of the dams, the reservoir was completed in 1889, with filling beginning in May 1889. Hallington received water from other reservoirs constructed further to the north-west, notably at Swinburn, Colt Crag and Catcleugh. The existing aqueduct and tunnel to Whittle Dene was found to be inadequate for the volume of water needed, and a second tunnel, parallel to the first, was constructed between 1898 and 1905. Narrow gauge railways were built to aid the construction of the first reservoir and the second tunnel.