[1] Douglas was born in Smethwick, Staffordshire, the oldest son of Sir Charles Fox and had two brothers and a sister.

[1] Sir Charles was a civil engineer and had designed, amongst other things, The Crystal Palace in Hyde Park.

[1] Douglas was instead articled to his father who had set up an engineering consultancy, Sir Charles Fox and Sons.

Douglas’ brother, Sir Francis Fox, married his wife’s sister, Selina Wright.

[3] In 1863 Douglas was made a partner and by 1865 the firm was involved in major projects in Britain, the US, Canada, southern Africa, India, Australia, and South America.

[1] From 1863 to 1866 Douglas and his father worked on the design of the railway viaducts and bridges at Battersea which would separate the lines coming from Waterloo from those from Victoria.