Perhaps the rail gauge is becoming a little worn? It is a rather shabby old thing, is it not, and it has been around over fifty years to my knowledge. Will Jones had it before the war, so I have little idea how old it is. It has no signs of welding on it, so I suppose it was forged - maybe on the old steam hammer? P. Pnjarvis (talk) 12:28, 14 September 2015 (UTC)
- Dingle Site - said to be 2nd tightest main line curve.
- Tyler's Curve - said to be sharpest on mainline, but radius increased when deviated.
- Coed y Bleiddiau - said to have been eased to suit rerailing for locomotive haulage.
- Curve Radius - result of search; needs to be tabulated.
- search for "curve" and get 148 matches.
- search for "sharp curve" and get 25 matches.
- search for "radius" and get 17 matches.
There is a format for citing articles in the NLA "Trove" newspaper articles, which Wikipedia and Festipedia understand.
Unfortunately, there does not appear to be a way of pinpointing the line in that article which can be citing.
This lack is a nuisance if the article is a long one. 
- "RAILWAY EXTENSION". South Australian Register (Adelaide, SA : 1839 - 1900). Adelaide, SA: National Library of Australia. 27 November 1867. p. 2. Retrieved 26 August 2015.
I understood the FR gauge to be 23 & 5/8 inches, which is almost precisely 600mm.
The South African steel sleepers used on the WHR have clips that allow for gauge widening. They have two steps at different distances, so if you install both at the smaller setting you get the straight track gauge (600mm), tuning one round moves the gauge out 5mm for medium curves and then if you turn both round you get 10mm of gauge widening for the sharpest of curves.
Interesting. It is not clear in the Dow 2014 reference page 445 whether the figures in his table refer to just the FR or apply to WHR as well. From what you say above it seems the WHR gauge may be marginally greater than the FR. I think this justifies an email to Fred. I am about to send. MarkTemple (talk) 17:04, 14 November 2016 (UTC)
Dow A (2014) The Railway, British Track since 1804 is the commanding reference for this material. I do not doubt he got his information from Fred Howes - former FR Civil Engineer now retired. If you want me to double check I could email Fred. MarkTemple (talk) 14:08, 14 November 2016 (UTC)