It was argued that rail would reduce freight costs and save travel time for passengers considering the very poor state of Queensland roads.

Priority was initially given to creating a rail link to the coast for the well-established and economically important Darling Downs pastoral region.

Located at the head of navigation, at the intersection of routes to the Darling Downs and Upper Brisbane Valley, it was the major inland port serving these areas.

The contract was subsequently awarded to the well known British railway builders Peto, Brassey and Betts whose price of £86,900 was the lowest of five tenders.

[1] Construction of this 21-mile (34 km) section from Ipswich, via Walloon, to Bigge's Camp (later named Grandchester) at the foot of the Little Liverpool Range commenced in February 1864 and the line was opened in July 1865.

The old line was retained as far as North Ipswich to serve the locomotive and carriage sheds and workshops.

Similarly all bridges on the Main Line were upgraded around the turn of the century to carry locomotives over twice the weight of the original ones.

After working as chief engineer on several lines, Stanley became responsible for the whole of the colony's railway network in 1892.

During the 1890s a number of large metal truss rail bridges were constructed to cross major streams making the connection of important towns and resources possible.

[2] The contract for the Sadliers Crossing Railway Bridge was awarded to J McCormick and Sons in February 1900.

The work was completed in March 1902 and the current bridge over the Bremer River at Sadliers Crossing came into usage.

The basic identifying features of the Pratt truss are the diagonal web members which form a V-shape.

In 1965 plans were prepared for replacing the longitudinals supporting the track with transoms and this work was completed during the following year.

In 1977 plans were prepared to replace the corbels on piers 9 and 17, and in 1994 the corner braces were removed to allow for the passage of over-height containers.

[1] Sadliers Crossing Railway Bridge was listed on the Queensland Heritage Register on 13 November 2008 having satisfied the following criteria.

This rail network, established in the 1860s, was vital for the development of the colony through opening land for closer settlement and freighting produce and resources to Queensland's ports.

From the 1890s the preferred design of large metal rail bridges to cross major waterways underwent several changes, to withstand flooding and to meet increased load requirements.

[1] The cantilevered pedestrian footbridge and access stairs attached to the upstream spans is a rare example of its type and is still in use.