A few years ago, they abandoned the previous Auckland station and constructed the present Britomart terminal at the end of a new tunnel. Bringing the Western line into the new route involved constructing what I'm told is the tightest curve in New Zealand. Local services are based on three lines, all terminating at Britomart. Two lines go South, one near the shore (called the East Line), one inland (called the South Line). These routes combine at Westfield and continue to Papakura. This is an important station, currently in the throes of a major rebuilding. The line further South is used by freight trains and the passenger service to Wellington. The West line is the third route. It shares the inland route as far as Newmarket, where West Line trains from Britomart reverse to reach the line to Waitemake. This line is single in part, but a major project, costing hundreds of millions of New Zealand dollars, is currently doubling the line.
In general, lines are double track, left-hand running. Track is 3'6" gauge, flat bottom on timber sleepers, although major renewals use concrete sleepers. The station at Britomart and the approach tunnel uses a solid, cast trackbed. Signalling is multiple aspect colour light. Stop signals are divided into Stop and Stay or Stop and Proceed types. Where necessary, an additional signal head is provided (either vertically in line with the first or displaced to the right) to allow permitted speed to be indicated to the driver. Most, but not all, of the three routes is part of a Centralised Traffic Control (CTC) system administered from Wellington. Because of the intensity of the service in the Auckland area, there are plans to devolve control to a sub-office in Auckland. There are two types of train operating the local services, diesel multiple units (DMU) and loco-hauled push and pull. The DMU design is based on the American Budd railcar, with underfloor-mounted engines driving via a fluid transmission. As speed increases, the drive is 'locked', to give good torque characteristics. There are two similar classes of DMU - the 'K' and the 'L', both built in Perth, Western Australia. In the earlier pattern, only one axle per power bogie is driven. The later version has both axles driven to improve adhesion.
