Inspired by the building of the real Ribblehead Viaduct in North Yorkshire, England between 1870 and 1874.
The second time Hans Matheson has played someone to do with someone of the name Blackwood, the first was in Sherlock Holmes where he was part of Lord Blackwoods gang.
The series is set in the fictional town of Jericho, a shanty town in the Yorkshire Dales of England.
In April 2016 ITV confirmed that a second series of the show was not going to be commissioned.