As a youth he assisted the surveyor Alexander Adie in surveying the roads on the Duke's estates and decided to be a civil engineer.

For this job he was obliged to build an embankment over Rosse’s Bay on the River Foyle, surmounting great difficulties.

The Ulverstone and Lancaster Railway Act received the Royal Assent on 24 July 1851 but work was not in full progress until September 1853 because workers and accommodation for them were not readily available.

This involved a 1 mile 8 chains (1.8 km) cast-iron girder viaduct between Bowness-on-Solway and Annan across the Solway Firth in Scotland.

The inspecting officer said that because of the thickness of ice, the size of the ice-floes, and the absence of wind, it was not surprising that the cast-iron columns had not withstood the shock.

This method of construction should be avoided in estuaries where the climate was subject to sudden changes in temperature and to blows from floating ice.

[10] He also worked in maritime engineering and was responsible for the construction of the docks at Avonmouth and Whitehaven[8] as well as the piers at Southport[5][8] and Southend.

[11] Brunlees was engineer, as well as one of the leading shareholders and directors, of the Mont Cenis Pass Railway, active mainly during planning and construction, 1864-1868.

[15] He died at Argyle Lodge in Wimbledon, London on 2 June 1892[1] and was buried in Brookwood Cemetery.