In the 1970s, as part of the expansion programme of the Merseyrail network, a burrowing junction was built at Hamilton Square so that trains heading towards New Brighton and West Kirby did not have to cross the path of trains coming from Rock Ferry on the flat crossing. Along with the construction of the loop tunnel in the centre of Liverpool, this improved the capacity of the Wirral Line, allowing increased train frequencies. The burrowing junction required the construction of a new -long tunnel, dug at a depth of between and , between Hamilton Square and Lorn Street and directly beneath the Town Hall and Market Street.