The Northern and Wirral Lines together have 67 stations and 75 miles of route, of which 6.5 miles are underground. Carrying over 100,000 passengers each day, they form one of the most heavily used railway networks in the UK outside London. The core of Merseyrail incorporates the original Mersey Railway, which was opened in 1886, giving Merseyrail the distinction of being the second oldest underground urban railway in the world and the first with lift access to its stations.