Bradfield worked on a variety of projects during his time at the New South Wales Department of Public Works, including the Cataract Dam near Sydney and the Burrinjuck Dam across the Murrumbidgee River.
In January 1909, he was promoted to the rank of assistant engineer with a salary of £400.
The following year he applied unsuccessfully for the position of foundation chair of engineering at the University of Queensland.
In 1913 he was appointed chief engineer for metropolitan railway construction, when he commenced his long association with secretary Kathleen Muriel Butler.
In 1915 Bradfield submitted a report outlining a grand scheme for Sydney's railways involving the electrification of the suburban railways, a city underground railway and the Sydney Harbour Bridge.
World War I led to the collapse of all three proposals.

During World War I, Bradfield worked with Professor Warren and Mr A.E. Cutler to establish the first civil aviation school, where pilots were trained for overseas service.

In 1924, Bradfield was awarded the degree of Doctor of Science (D.Sc.)
for a thesis titled "The city and suburban electric railways and the Sydney Harbour Bridge", the first doctorate in engineering awarded by the University of Sydney.
In 1935 the University of Queensland awarded him the ad eundem degree of Doctor of Engineering (D.Eng.).
Bradfield worked on a variety of projects during his time at the New South Wales Department of Public Works, including the Cataract Dam near Sydney and the Burrinjuck Dam across the Murrumbidgee River. In January 1909, he was promoted to the rank of assistant engineer with a salary of £400. The following year he applied unsuccessfully for the position of foundation chair of engineering at the University of Queensland. In 1913 he was appointed chief engineer for metropolitan railway construction, when he commenced his long association with secretary Kathleen Muriel Butler. In 1915 Bradfield submitted a report outlining a grand scheme for Sydney's railways involving the electrification of the suburban railways, a city underground railway and the Sydney Harbour Bridge. World War I led to the collapse of all three proposals.
During World War I, Bradfield worked with Professor Warren and Mr A.E. Cutler to establish the first civil aviation school, where pilots were trained for overseas service.
In 1924, Bradfield was awarded the degree of Doctor of Science (D.Sc.) for a thesis titled "The city and suburban electric railways and the Sydney Harbour Bridge", the first doctorate in engineering awarded by the University of Sydney. In 1935 the University of Queensland awarded him the ad eundem degree of Doctor of Engineering (D.Eng.).
John Bradfield (engineer)