<Tr> <Th> Boat - passable </Th> <Td> Yes (with permission) </Td> </Tr> <P> The Standedge Tunnels are four parallel tunnels beneath the Pennines in northern England . Three are railway tunnels and the other is a canal tunnel . They are located at the Standedge (pronounced Stannige) crossing point between Marsden and Diggle, across the boundary between the West Yorkshire and Greater Manchester conurbations . Before boundary changes in 1974, both ends of the tunnel were in the West Riding of Yorkshire . </P> <P> The canal tunnel is on the Huddersfield Narrow Canal . It opened in 1811 and is the longest and oldest of the four and is the longest and highest canal tunnel in the United Kingdom . The first, single - track railway tunnel was completed by the London and North Western Railway (LNWR) in 1848 on the line between Huddersfield and Manchester and a second, parallel, single - track tunnel opened in 1871 . The LNWR opened a third, double - track tunnel in 1894 . All four tunnels are linked by cross-tunnels or adits at strategic intervals, which allowed the railway tunnels to be built quickly, reducing the need for construction shafts, as waste could be removed by boat . </P> <P> Of the railway tunnels, only the one built in 1894 is currently used for rail traffic . Closed in 1943, the canal tunnel was re-opened in May 2001 . The Standedge Tunnel Visitor Centre, at the Marsden end, is a base for boat trips into the tunnel and hosts an exhibition depicting the different crossings . </P>

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