High Quality Content by WIKIPEDIA articles! An Auckland, New Zealand city centre rail tunnel (official name City Rail Link (CRL) and variously called `tunnel`, `deviation`, `loop` or `link` over the decades) has been proposed at various times during Auckland`s history. All schemes, to differing degrees, propose to increase the capacity of the rail network, add new connections and/or train stations in the city centre or nearby suburbs, and reduce journey times for train passengers, especially from the western suburbs.