Talk:Moelwyn Tunnel

Old and New Tunnels

I am unhappy with these descriptions of the tunnels. Old Moelwyn Tunnel is recorded twice and an entirely extraneous tunnel, nothing to do with FR, is entered beneath. Neither are Roman mining tunnels relevant. From memory the ruling grade of the New Moelwyn Tunnel is 1 in 75 - Adrian has my set of plans - but I am not able definitively to say it is not the 1 in 99? entered. I have deleted the fictitious brick lining of the Old Tunnel (from personal observation) and increased the number of shafts from 1? to 2? I have seen two shafts on top but just wonder if there may have been a third. I never walked right through the Old Tunnel - it was dark, sooty and wet - so only went 50 yards inside it, but have walked the Tunnel Newydd. It was evident later that the plug near the top end did not stop water percolating through the fractured rocks around the tunnel and the Deviationists were able to fill their reservoir from this leakage. Their dam is still there, some yards inside the bottom end of the Old Tunnel.Pnjarvis (talk) 16:53, 10 September 2015 (UTC)

In discussing "rathole" tunnels, it make sense to give more than one example, and since FR has/had only one nasty tunnel, the secondary examples have to come from elsewhere. FarleyBrook (talk) 01:47, 11 September 2015 (UTC)

I'm with Pnjarvis on this one. The old tunnel has 2 entries when it is the same tunnel. The "1863 tunnel" really should be removed. Furthermore, so should non-FR/WHR entries; I do not believe they are appropriate. Tony E. (talk) 07:31, 11 September 2015 (UTC)

I doubt the title 'rathole' ever formed part of the description of Old Moelwyn Tunnel, whatever may have been the vulgar parlance among Deviationists etc. Pnjarvis (talk) 16:06, 11 September 2015 (UTC)

The two versions (horse and steam) of the Old M. Tunnel can be combined, though care must be taken to maintain sortability. FarleyBrook (talk) 02:19, 12 September 2015 (UTC)

There are no "two versions"; it was the same tunnel unaltered.Heritagejim (talk) 08:11, 12 September 2015 (UTC)

The template might also be renamed Template:Tunnels. FarleyBrook (talk) 02:28, 12 September 2015 (UTC)

Sandbox

---

Comparison of Tunnels

N	Year	Link	Gradient	Length	Curvature	Ventilation	Width	Height	Sides	Roof	Line	Remarks	Notes
101	1842	Old Moelwyn Tunnel	1 in 80?	730yd	N/A	N/A	8' 0"	9' 6"	Straight	Semi-circle	Brick??	Replace 1836 inclines	Nasty
106	1977	Moelwyn Tunnel	1 in 99?	275yd	A	B	??	??	Straight	Low arc	Shot Concrete (Shotcrete)	Deviation avoids flooding	Comfortable
999	1066	Roman Tunnels, Mining									----		C

Gallery

• 
  Tunnel profile Old Moelwyn Tunnel
• New tunnel looks much wider than the old.
  New tunnel looks much wider than the old.
• 
  Tunnel profile New Moelwyn Tunnel

Tunnels and Loading Gauge, etc.

Comparison of Tunnels, etc.

N	Year	Link	Gradient	Length	Curvature	Tracks	Ventilation	Width $	Height $	Sides	Roof	Lining	Engineer	Remarks	Notes
101	1842* 1863+	Old Moelwyn Tunnel * Horse Power + Steam power	1 in 80? x	730yd	Straight	1	3	8' 0"	9' 6"	Straight	roughly Semi-circle	Stone portals; unlined within	J. Spooner	Replaced 1836 inclines	* No Problems + Nasty, confined, wet
106	1977	New Moelwyn Tunnel	1 in 80? x	275yd	Straight	1	None	11' (+/- 3")	12' (+/- 6")	Straight	Low arc	Shot Concrete (Shotcrete)	M.A. Schumann; the Three Miners	Deviation avoids flooding	Comfortable
201	1851	Garnedd Tunnel	1 in 80; dips under portals	60yd	Slightly curved	1	No	8' 0"	ca.10'	roughly straight	Semi-circle, stone portals	Mostly unlined; brick piers in places	J. Spooner	Deviation of 1836 route
701	1836	FR Structure gauge						8' 0" various cuttings, now less; was ca.7' at Cemetery 1963	8' 6" (to 1956) but 9' 8"(since 1963) Rhiw Plas			Smallest bridge or tunnel			GS
705	1836	FR Loading gauge						6' 2" plus in-swing at carriage centres	9ft +/- 3ins			Largest rolling stock			GL

• Notes: N/A = Not Available.
• x Notes: Ruling Grade about 1 in 80.
• + Notes: At ruling gradient.
• $ Notes: Structure gauge and loading gauge are not simple rectangles.

Gallery

• 
  Tunnel profile Old Moelwyn Tunnel
  An unpleasant tunnel in steam days.
• 
  New tunnel (right) looks much wider
  than the old tunnel (left).
• 
  Tunnel profile New Moelwyn Tunnel
• 
  Garnedd Tunnel west portal

Rathole

A rathole tunnel is so-called when a combination of factors make it difficult, unpleasant, and even dangerous to operate, including

• gradient too close to the ruling gradient.
• length longer than the "momentum distance".
• wet rails from steam and/or water seepage.
• unhelpful wind direction.
• train load too close to full load.
• loading gauge too close to the structure gauge.
• awkward stop at bottom of tunnel.
• insufficient time between trains for smoke to clear.
• single line rather than double line.
• lack of escape route for crew in case of stall.
• even great engineers made mistakes and rathole tunnels.

There is a standing instruction to enginemen on the FR that in the event of the engine coming to a stand in a tunnel, the train must run back by gravity outside the tunnel before any effort is made to blow up steam.

---

By FarleyBrook (talk) 04:01, 16 August 2015 (UTC)