It was passed in September of that year and provided for the construction of a line by the government from Ipswich to Toowoomba, Dalby and Warwick - the Southern and Western Railway as it was first called.

But in 1899 an official three-year program was commenced to ease curves on the railway and replace high timber bridges with concrete culverts due to the increasing weight of rolling stock.

The Commissioner's Annual Report for 1900 (p 76) notes:[1]Deviations on the Main Range for the purpose of easing curves and substituting earth embankments and concrete works for the iron bridges, which have been condemned as being too light for the increasing weight of rolling stock, have been carried on continuously by day labour.

[1] Swanson's Bridge is located on the Main Range railway, 1.5 kilometres (0.93 mi) south-south-west of Blue Mountain Heights and 6 kilometres (3.7 mi) north of Toowoomba, over an unnamed gully near the top of the Toowoomba Range.

[1] It is detailed with prominent cornices at the bases of the arches and incised lines on the spandrel walls of a form similar to the joints that would occur in a stone bridge.

[1] Swansons Rail Bridge was listed on the Queensland Heritage Register on 21 October 1992 having satisfied the following criteria.

Swanson's bridge has aesthetic value for its pleasing viaduct design as well as its position in the midst of the bush of the Toowoomba Range giving it a dramatic outlook from the escarpment it is built upon.

[1] The place has a special association with the life or work of a particular person, group or organisation of importance in Queensland's history.

It also has special association with the work of William Page, Chief Engineer, who was responsible for the design of the bridge.