Dredge was employed from 1858 to 1861 as an engineer in the office of Daniel Kinnear Clark. In 1862, he was employed by John Fowler, and worked on the District Railway in London. In January 1866, he ventured into engineering journalism, joining the weekly journal "Engineering". In the late 1860s, he mainly illustrated for the journal, writing the occasional article, attending the great Paris Exhibition of 1867, where the journal writers "discovered a fund of new technology on which to report". However, in 1870, on the death of editor Zerah Colburn, he became a co-editor of the journal with William Henry Maw. Maw not only considered Dredge to be a friend, but also his senior in technical matters. As editor of "Engineering", Dredge was a surveyor, documenting numerous bridges and photographing them in the 1890s; a notable contribution was his "Thames Bridges, from the Tower to the Source" (1897). In 1901, he founded a monthly supplement to "Engineering", a journal named "Traction and Transmission", but it only lasted for three years.