The first lines
In essence the early development of the Queensland Railways was a transfer of English railway operation, management, and technical development to a distant colony.
For locomotives, rolling stock, signalling, station buildings and staff, the government engaged Sir Charles Fox as consulting engineers. They provided a number of innovative - and not always successful - designs for the narrow gauge, and in terms of station design, their plans were wildly extravagant for a young colony.
… The original decision to build a railway was not justified because it was expected to be profitable, but because of its role in the economic development of the colony. This development role has been paramount and has only recently lost its importance when heavy road transport - subsidised by the state and by other road users in less visible ways - was allowed almost unfettered competition with rail.
John Kerr, Author of Triumph of Narrow Gauge, the acclaimed history of the QR

Chronology
1863:
Introduction of Southern and Western Railway Bill to Parliament.
Selection of 1067mm gauge
Appointment of first Commissioner, Abram Fitzgibbon.
1864:
Turning of first sod at North Ipswich.
1865:
Opening of first railway line Ipswich-Bigges Camp
1866:
Jun 1 - Opening railway through Victoria Tunnel to Gatton
1867
May 1 - Opening of Railway Ipswich to Toowoomba
Sep 19 - Opening from Rockhampton to Westwood
1868
Apr 16 - Opening of Railway Toowoomba to Dalby
1869
Mar 11 - Opening of Southern Railway Gowrie Junction to Hendon (near Allora)