The railway line between Morwell and Mirboo North was approved for construction by the Victorian parliament in November 1880, as the result of a great deal of agitation by the local settlers. Roads in the area at the time were virtually non-existent and it was difficult for settlers to bring in their families and supplies and almost impossible to send produce out in an economic manner.
Construction commenced in January 1883 and work progressed very slowly due to the difficult terrain and the very wet weather. The surveyed route did not follow the contours, but necessitated immense cuttings and massive embankments be made to reduce the gradient to workable levels and the building of 29 bridges in 20 miles to cope with the watercourses along the way.
The rail line to Boolarra opened on 10th April 1885, to Darlimurla on 8th September 1885 and the completed line to Mirboo North was formally declared open on 7th January 1886. The total length of the line was 20 miles 15 chains, at a total cost of construction of approximately £75,000 – a massive job for the day. There are four stations on the line - Yinnar at 8 miles, Boolarra at 12 miles, Darlimurla at 16 miles and Mirboo at the end of the line at 20 miles.
With the opening of the first section of the line to Boolarra on 10th April 1885, the timetable provided for a "Mixed Train" leaving Morwell each morning after connecting with the Melbourne train, arriving at Boolarra at 12.25 p.m. The train departed Boolarra next day at 7.15 am, the engine being stationed at Boolarra overnight. When the Darlimurla section was completed, the trains went on to that terminus, arriving at 12.45 pm and departing the next morning at 6.55 am.
Occasional passenger trains were run during holiday seasons and the line soon warranted a twice daily service of mixed trains, which was introduced with a new timetable on 3rd November 1886. Timber and timber products formed the main traffic of the line of the early days, but as the land was cleared, tonnages of agricultural products increased including potatoes, butter, chaff and hay. The popularity of rail travel and transport declined and between 1903 and 1912, trains were reduced to three times weekly and services were based at Morwell rather than at Mirboo North.
With the merging of the Boolarra and Mirboo North Butter factories outward revenue again increased until a 3-week rail strike in November 1950 jeopardised this and other industries, that were forced to look at road transport to move their products. When the strike finally finished, most of the industries never returned to the rail, having found that road transport was more economical.
One commodity that was railed from Boolarra and Mirboo North in large quantities was the mineral rock Bauxite, a sedimentary rock used in cement, chemicals, face makeup, drink cans, dishwashers, siding for houses and numerous other aluminium products. Up to 12 rail trucks a day were railed from Boolarra during the 1940's and 22 wagons per day were railed from Mirboo North in the years between 1967 to 1974.
During the late 1960's and early 1970's, Superphosphate formed the bulk of the inward traffic on the line. Superphosphate is a fertilizer mainly used as a maintenance fertiliser that was also ideal for pastoral development and arable/horticultural situations.