We seem to be missing narrow gauge tunnels - the Ffestiniog on which our narrow gauge vehicles are based has a tunnel, so we probably ought to have one.
should be a simple ordeal. splicing together tube tunnel entrance with narrow gauge track should give the desired results.
The Ffestiniog tunnel isn't an original feature it was built in the 1980s when the line was reconstructed after part of the trackbed was lost due to a valley being flooded by a dam. The Welsh Highland Railway has some tunnels dating to the 1920s, don't know about other narrow gauge railways before that.
The present Ffestiniog tunnel is indeed new, but the Ffestiniog had an earlier tunnel as part of the original line (both old and new tunnels are called the "Moelwyn tunnel"), which is now under some considerable amount of water as a result of the dam. This tunnel had a particularly restrictive loading gauge, and earlier Ffestiniog railway carriages from before the preservation era are significantly smaller than the carriages that run now on the line in consequence:
(http://farm9.staticflickr.com/8425/7819488680_55367626b9_b.jpg) (http://www.flickr.com/photos/14730981@N08/7819488680/)
On arrival at Blaneau (http://www.flickr.com/photos/14730981@N08/7819488680/) by James E. Petts (http://www.flickr.com/people/14730981@N08/), on Flickr