Between Newquay Railway Station and Tolcarn Junction the line crosses the Trenance valley on a 154 yard (141m) viaduct.
The first structure, opened on 29 January 1849, was a timber structure on stone piers. It was much lighter than the similarly-constructed Cornwall Railway viaducts that were built a few years later, and very different from the imposing granite Treffry Viaduct built by Joseph Thomas Treffry for his Par tramway.
The piers were raised and new wrought iron girders installed ready for the opening of the line for locomotives in 1874.
This was replaced by the present masonry structure on 27 March 1939.
The viaduct carried two tracks from 20 March 1946; the line to Tolcarn Junction was singled on 23 November 1964 but the second line was retained for shunting purposes until the rationalisation in the 1980s.