high-speed intercity services from King's Cross to Edinburgh Waverley operated by the London North Eastern Railway at around a 20-minute frequency. It is the northern terminus of slower commuter services from Horsham via Gatwick Airport and central London operated by Govia Thameslink Railway. It is a major railway junction where a number of cross-country routes converge: • East Midlands Railway operates through services between Norwich, Nottingham and Liverpool Lime Street that call at Peterborough, as well as trains on the line to Lincoln. • CrossCountry provides connections west to Leicester and Birmingham, and east to Ely, Cambridge and Stansted Airport. • Greater Anglia also runs trains to and from Ipswich via Soham. Water The River Nene, made navigable from the port at Wisbech to Northampton by 1761, passes through the city centre. The Nene Viaduct carries the railway over the river. It was built in 1847 by Sir William and Joseph Cubitt. William Cubitt was the chief engineer of Crystal Palace erected at Hyde Park in 1851. Apart from some minor repairs in 1910 and 1914 (the steel bands and cross braces around the fluted legs) the bridge remains as Cubitts built it. Now a Grade II* listed structure, it is the oldest surviving cast iron railway bridge in the UK. By the Town Bridge, the Customs House, built in the early eighteenth century, is a visible reminder of the city's past function as an inland port. The Environment Agency navigation starts at the junction with the Northampton arm of the Grand Union Canal and extends for ending at Bevis Hall just upstream of Wisbech. The tidal limit used to be Woodston Wharf until the Dog-in-a-Doublet lock was built downstream in 1937. Road The A1/A1(M) primary route (part of European route E15) broadly follows the path of the historic Great North Road from St Paul's Cathedral in the heart of London, passing Peterborough (Junction 17), and continuing north a further to central Edinburgh. In 1899 the British Electric Traction Company sought permission for a tramway joining the northern suburbs with the city centre. The system, which operated under the name Peterborough Electric Traction Company, opened in 1903 and was abandoned in favour of motor buses in 1930, when it was merged into the Eastern Counties Omnibus Company. Today, bus services in the city are operated by several companies including Stagecoach (formerly Cambus and Viscount) and Delaine Buses. Despite its large-scale