Built as a narrow gauge (3ft6in - 1067mm) line from Peterborough to Orroroo in 1881, it was extended to Quorn in 1882 where it joined the SAR Main Northern Line (narrow gauge) from Port Augusta to Oodnadatta. The Northern Line was transferred to the Commonwealth Railways in the early 1920s. When it was extended to Alice Springs in 1926-29 it was renamed to the Central Australia Railway .
When the standard gauge (4ft8.5in - 1435mm) Transcontinental Railway from Port Augusta to Kalgoolie was completed in 1917, the Peterborough-Quorn Line became the route for all Transcontinental and Central Australia rail traffic until 1932 when a more direct broad gauge (5ft3in - 1600mm) line from Port Pirie to Port Augusta was completed.
During the 1940s many of the passing loops on the line were lengthened to handle the longer troop and military freight trains. During the 1950s the main Central Australia Railway was diverted away from Quorn and the remaining line was truncated at Hawker. This significantly reduced the traffic and led to the removal of several passing loops on the Peterborough-Quorn line. The line from Port Pirie to Broken Hill was converted to standard gauge during 1969-1970 which isolated the Peterborough-Quorn Line from the rest of the narrow gauge network (the Port Augusta to Quorn line was closed in 1956).
In the 1960s there were 3 weekly return freight services between Peterborough and Quorn. The speed limit on the line in the 1960s and later was 30 to 35mph. The only exception was for the Brill passenger rail motors which had a limit of 47mph (which was the maximum possible speed of the vehicle).
In January 1970 all steam locos were withdrawn and replaced by two diesel locos based at Peterborough, but one was later withdrawn. Limited regular freight services to Orroroo ran until 1973 when they were replaced by a road vehicle but trains still serviced the grain silos at Orroroo, when needed. By 1979 there was only one weekly return service to Quorn and this usually terminated at Carrieton. The last timetabled return freight service to Quorn ran in 1980. Special steam passenger excursion trains still ran from Peterborough to Quorn upto the mid 1980s.
The line from Eurelia to Quorn was closed in March 1987 as it was regarded to be in poor condition. This was followed by the closure of the line from Peterborough to Eurelia in November 1988. The last scheduled services on the line were grain movements to clear the silos at Orroroo in October 1988 but the Steamtown Peterborough Railway Preservation Society continued to run excursion trains to Eurelia until 2002.
By 2008 the line south of Bruce had been removed with the original track preserved in only a few places of significance (Black Rock and Wallaway).