The Dargaville Branch is a branch line railway that leaves the North Auckland Line not far south of Whangarei and runs westward to Dargaville. Construction of this relatively short line took approximately two decades, and when it was completed, it linked the now closed Donnelly's Crossing Section with the national rail network. Although the Dargaville Branch's future is uncertain, it continues to operate today.
The Dargaville Branch was built relatively late in comparison to most railway lines in New Zealand. Construction from Waiotira on the North Auckland Line commenced in 1922. Dargaville, however, was not reached for another eighteen years. The first twenty-two kilometres through unstable country took six years to build, with the line not opened to Kirikopuni until 15 May 1928. In January 1931, the line was open to Tangowahine, sixteen kilometres from Dargaville, but construction ceased for five years due to the Great Depression. In 1940, trains commenced running to Dargaville, but the old railway station (used by the Donnelly's Crossing Section) was closed and a new station built at a different location, delaying the formal opening of the Dargaville Branch until 15 March 1943, over twenty years after construction began.
At one time, there was a proposal to build a railway from Kirikopuni north to Kaikohe, but considering the presence of a line from Whangarei, this proposal was discarded. Some other construction did occur around Kirikopuni, however - the line was initially constructed with a balloon loop into the town, which was two kilometres north of the direct line to Dargaville, but a bypass eliminated the loop in 1943.
Dargaville Branch operations have never been spectacular. From its opening until March 1967, mixed trains carrying both passengers and freight ran to connect with passenger services on the North Auckland Line - the Northland Express (Auckland-Opua and return) until November 1956, and then the 88 seater railcars (Auckland-Okaihau and return). After March 1967, the line carried freight only, and in recent years, its future has been under question. At one point in the first half of the 2000s, it was closed for six months, but traffic has now returned and the line is operated from Whangarei. A daily return train is scheduled from Monday to Friday but it only runs when required. It takes roughly three hours both ways; the service to Dargaville arrives in the mid-morning and departs before lunch, arriving in Whangarei in the mid-afternoon.
Typical motive power on the Dargaville Branch from its opening until the mid-1960s were steam locomotives of the AB and J classes. When the line was dieselised, DA class diesel-electrics took over and worked the line until 1988. Nowadays, the DBR class and DC class comprise the motive power seen running to Dargaville.
- Churchman, Geoffrey B., and Hurst, Tony; The Railways Of New Zealand: A Journey Through History, HarperCollins Publishers (New Zealand), 1991 reprint