Opened : 1907

Closed : 1938

Engineering code : CRY

Length: 150m

The Tongwynlais Tunnel was constructed by the Cardiff Railway to allow the railway to be fitted through the narrow Taff's Well gap between the Castell Coch hillside and the Barry Railway and Glamorgan Canal. The tunnel was dug out in 1977 as part of the preparatoty works for the the A470 dual carriageway. It would have been located just north of the Taff's Well interchange.