From the wikipedia page on Otiria
Otiria is presently the northernmost operational point of the national railway network. It is the terminus of the North Auckland Line, although a disused siding extends into Moerewa. Otiria was a railway junction until the mid-1980s. The Opua Branch section of the North Auckland Line ran northeast to Kawakawa and Opua, while the Okaihau Branch ran northwest to Kaikohe and Okaihau. The railway through Otiria was originally built in the early 20th century to connect Opua and Kawakawa with Whangarei; the through route opened on 13 April 1911.[3] This was quickly followed by the commencement of work on the Okaihau Branch from Otiria; it opened to Kaikohe in May 1914 and Okaihau in October 1923.[4]
In December 1925, passenger trains offering direct service to and from Auckland began running through Otiria. This was initially the Northland Express between Auckland and Opua, with carriages for Okaihau detached in Otiria. It was cancelled in November 1956 and replaced by 88 seater railcars that ran between Auckland and Okaihau. Due to declining patronage and the poor reliability of the railcars, this service ended in July 1967.[5] Mixed trains to Whangarei continued to operate; the final passenger service through Otiria ran on 18 June 1976.[6] The line from Otiria to Opua ceased to be used in 1985, and when the Okaihau Branch closed on 1 November 1987, Otiria became the northernmost locality served by rail in New Zealand.[7] Presently, one freight train is timetabled to operate every weekday each way between Otiria and Whangarei.[8]
Some of historical information ( 196? ) : When I was based at the Whangarei Locomotive Depot and would be booked on Goods Train 77 Ex Westfield , a lot of the Freight would be destined to destinations like Kaikohe and Kaitaia. Departure from Whangarei would be about 4-30 am. This train had a carriage attached to take passengers to all those little settlements along the way like Motatapu, Maramako, Hukerinui. On arrival at Otiria a lot of the tonnage would come off Train 77 to be placed on the goods train, Number 1039 For Kaikohe and Okaihau and Train Number 1039 also would have passenger carriages at the end of the train to carry passengers onto Kaikohe and Okaihau. Returning from Okaihau to Otiria Goods Train Number 1040 would also consist of a passenger carriage back to Otiria. There were approximately 6 crews based at Otiria who would also run a shunt down to Opua consisting of export meat from the near by freezing works for shipping out from Opua. All this export meat would be railed in those old refridgerated bogie V wagons. Following the birth of the container age in 1970 nearly all this tonnage was railed right through to the port in Auckland (or to Marsden Point had there been a Marsden Point Branch). Otiria locomotive crew would also work an evening goods train service to Whangarei where they would take Train 163 from Auckland to Otiria. Train 163 would always arrive into Whangarei on the mainline at the station platform. Norm Daniel ( Nov 2017 )