Normanton to Croydon line which always remained isolated. At its peak in 1932, the network totaled . Changing transport patterns resulted in the closure of many development branch lines from 1948 onwards, but at the same time the main lines were upgraded to provide contemporary services, and from the 1970s an extensive network of new lines was developed, particularly to service export coal mines. Electrification Commencing in November 1979, the Brisbane suburban network was electrified. In 1978, discussions were commenced on possible electrification of the Blackwater and Goonyella coal networks. This was due to an expected increase in coal traffic across the networks, ageing diesel-electric locomotive fleet and the increase in diesel fuel costs. By early 1983, a decision had been made to electrify the networks and by early 1984, contracts were already starting to be let for the new locomotives and other works for the project. The decision was made to electrify with the 25 kV AC railway electrification system as used on the Brisbane suburban network. This would allow future connection of the Brisbane network with the coal networks via the North Coast line. The project was to be carried out in four stages: Stage 1: Electrification of the main line from Gladstone to Rockhampton, including parts of Rockhampton marshalling yard, then west to Blackwater and the coal mines in the area. This was a total of of track. Stage 2: Electrification of the coal lines south of Dalrymple Bay and Hay Point, then west through the Goonyella system, south-west to Blair Athol and south to Gregory – linking the Goonyella system to the Blackwater system. This was a total of of track. Stage 3: Electrification of the main western line from Burngrove to Emerald. This would allow electric freight from Rockhampton to Emerald. Stage 4: Electrification of the line from Newlands coal mine to Collinsville and north-east to Abbott Point. This stage never went ahead. In 1986, it was decided to electrify the North Coast line between Brisbane and Gladstone instead and this became known as Stage 4. Interstate expansion In September 1999, Queensland Rail was rebranded as QR. In March 2002, Queensland Rail purchased Northern Rivers Railroad and rebranded it Interail, fulfilling a long-held ambition of expanding beyond its state borders. In March 2003, Queensland Rail entered the Hunter Valley coal market when Interail commenced a contract from Duralie Colliery to Stratford Mine. Another coal contract