Soon after passenger expresses began to operate, but the twisting, rugged nature of the railway line meant that they did not achieve particularly fast speeds.
The Northland Express was the premier service north of Auckland and it operated thrice weekly in each direction.
By the 1950s, the Northland Express was able to maintain a schedule of 5 hours and 20 minutes on the section between Auckland and Whangarei and was operated by steam locomotives such as the J class.
They did not operate entirely the same route as the Northland Express; at Otiria, instead of heading northeast on the Opua Branch, they ran northwest to Okaihau.
From this time, Opua's passenger services were provided by mixed trains from Whangarei and they were not timetabled to provide a connection with the railcar service, although the Dargaville mixed continued to meet the railcars until March 1967, when passengers ceased to be carried on the Dargaville Branch.