At the start of the 1870s, a number of plans were made for a branch line from the Main North Line, then under construction, to
Oxford. This was in response to the realities of the appalling communication and slow transport of the time. One plan, made in 1871, called for a line from Kaiapoi to Oxford, but this was seen as a threat to the interests of a proposed line from
Rangiora to Oxford. Intense campaigning from groups in support of either line led to the government's decision to build two branches, one from Rangiora to Oxford and another from Kaiapoi to West Eyreton. Despite warnings the line to West Eyreton would never be profitable, contracts for construction were let in 1873, and by 1875, construction was proceeding well, with the line opened to West Eyreton on 17 December 1875. This was intended to be the terminus of the branch, but in an attempt to make it profitable, work began the next year to link it with the Oxford Branch. This was completed on 1 February 1878 and linked West Eyreton with Bennetts Junction.
Break of Gauge For a while, a
break-of-gauge existed at the junction with the Main North Line in Kaiapoi. The Main North Line had been built with the
Canterbury Provincial Railways'
broad gauge of , while the Eyreton Branch was built to the then newly accepted national standard of (internationally, a
narrow gauge). In 1876 provincial governments were abolished and Canterbury Provincial Railways were absorbed by the central government. By 1877 the Main North Line was converted to a
gauge of and the break-of-gauge was eliminated. == Operation ==