I was under the impression that the floor of Garnedd Tunnel was lowered during the reconstruction of the line during the 60's (possibly when the Army were working on the line?). --Edward Harris (talk) 15:43, 17 September 2008 (UTC)
Questions about height
According to this article, the height limit was formerly dictated by the Old Moelwyn Tunnel, but is now by the Garnedd Tunnel and Rhiw Plas bridge. About the Old Moelwyn Tunnel, both that article and this one say "The tunnel measured just 8' wide and 9' 6" high"; about the Garnedd Tunnel and Rhiw Plas bridge, I've found no measures. But the article about Van 1 says "nowadays the loading gauge has been extended from 8ft 6ins high to 9ft 8ins", presuming a former height margin of a whole foot. Seems much to me. The article about Vale of Ffestiniog gives its height as 9' 5½", which on one hand is 2½" less than 9' 8", on the other would yield a more normal margin if 9' 8" is the outer envelope. 18.104.22.168 -(talk) 12:40, 20 October 2011 (UTC)
Loading Gauge or Structure Gauge
Are these measurements (8' wide and 9' 6" high):
- Loading gauge - the smaller values; maximums
- Structure gauge - the larger values; minimums ? FarleyBrook (talk) 02:03, 11 September 2015 (UTC)
- Width 6' 4"
- Height: N/A
This suggests that:
- 6' 4" is the maximum width of the loading gauge for pieces of rolling stock.
- 8' 0" is the minimum width of the structure gauge such as overbridges, signals, and tunnels.
- and similarly with the height. FarleyBrook (talk) 02:13, 11 September 2015 (UTC)
I don't think the situation is as simple as you think. Firstly, clearances are much greater on the Deviation than on the rest of the line due to modern regulations - when the line was originally built there were no regulations!
If you have a longer vehicle then it has to be narrower to give clearances on curved sections and I understand that carriage 150 is slightly wider than earlier carriages as it has flush door handles which save a few inches. I doubt anyone will give you exact widths & height. Heritagejim (talk) 08:02, 11 September 2015 (UTC)
- I agree that things are more complicated than meets the eye, but:
- Should add a clause that the LG and SG depend on the shape of these gauges. FarleyBrook (talk) 11:03, 11 September 2015 (UTC)
Mind your head
One of the carriages has a sign "Mind your head", illustrating a problem with a small loading gauge.