Construction of a road to Bluff (called Campbelltown until March 1917) was approved by the Otago Provincial Council in 1859, but the swamp defeated the builders.
[5] On 8 August 1863 "Lady Barkly", the first locomotive to steam in New Zealand,[6] ran on a small section of track on Invercargill Jetty, and a 12 kilometres (7.5 mi) line from Invercargill to Makarewa (today part of the Ohai Branch) opened on 18 October 1864, built with wooden rails, as an apparently cheaper alternative to iron rails.
Construction from the Invercargill Harbour and Wharf area soon became troublesome with the direct route across the New River estuary proving difficult due to the deep swampy mud needing to be piled up with rocks and hardwood poles.
The line made it to Clifton and easier ground as the raised formation skirted the banks of the east arm of the estuary passing over the Waimatua Creek.
Helping with the construction, a small branch line was laid to the Mokomoko inlet jetty with coastal shipping off-loading supplies.
The local Sheriff seized all assets on the line, a form of receivership enacted, allowing the finishing off work to continue.
Little remains of the harbour crossing and Invercargill Wharf due to draining and substantial land reclamation over 100 years, some bridge piles are still visible.
A Jetty already existed at the eastern side of the inlet entrance for the local settlers and at one point was promoted as an alternative to both Campbelltown and Invercargill's port ambitions.
It was decided to lay a spur line off the still incomplete Bluff mainline to the jetty which consisted of a large curve that required deep drains on each side.
The branch was only ever useful as a supply line and few passengers were carried, mainly from the small coastal steamers that would land at the jetty instead of risking the voyage up to Invercargill.
[7] When containerisation was introduced and freight transportation trends changed, Bluff was not selected to be developed as a container port, but it and the railway have remained busy with traffic such as frozen meat, wool, and wood chips.
In 2016 a new port owned multimodal distribution centre was completed on an unused area of the Invercargill railway yards next to the Bluff Line entrance.
For many years, passenger traffic on the line was heavy, with 12,000 fares travelling in a single day to a regatta in Bluff on 1 January 1900.
The remaining service was operated for school children, running from Bluff to Invercargill in the morning and returning in the late afternoon.
The reason being the only turning facilities at Bluff was the "Wye" layout that was part of the wharf's lighter rail access bridges.
Southland was at the forefront of a major agricultural export boom and the now ageing town wharf simply couldn't cope with the heavy demands of rail traffic and busy shipping causing it.
The junction points to the new port facility faced Invercargill to allow direct access for mainline train movements.
Minimal trackage on the town's station site remains to serve the substantial cool stores located along Gore Street.
The only substantial structures are now the station goods shed and a re-positioned wagon turntable to represent the numerous former level crossings on Gore Street.
The new inland SouthPort multimodal container terminal located on a portion of the Invercargill railway yard has returned considerable tonnage to the line.
Regular maintenance of the line including sleeper replacement has allowed for heavier tare weight wagons to now operate over it.
Apart from wayside stations closing, the line has needed no major reconstruction work mainly because of the legacy of its excellent, if somewhat costly, 19th-century British railway construction methods.