From Festipedia, hosted by the FR Heritage Group

Rail Gauge[edit]


Template view[edit]

Tunnels and Loading Gauge, etc.[edit]

Comparison of Tunnels, etc.

N Year Link Gradient Length Curvature Tracks Ventilation Width
Sides Roof Lining Engineer Remarks Notes
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")
(+/- 6")
Straight Low arc Shot Concrete
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.



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.

Zig Zags and Incline Planes[edit]

Incline Planes use ropes to lift load up and down steep gradients.

Zig Zags are paths in rising ground which are forced by difficult terrain to make 180 degree turns every so often.


With roads, the sharp turn may be achieved with so-called "hairpin turns".


With railways, the train has to reverse direction. Ideally there should be an even numbers of turns so that overall, the train continues in the same direction.

Zig zags are cheaper and quicker to build than alternative tunnels.

The length of the top and bottom roads where the train reverses limits the size of the train.

Time line[edit]

Inclines and zigzags are ways of dealing with steep terrain without resorting to major tunnels.

Zig zags for road probably are as old as roads and paths.

Zig zags for railways probably go back as far as there have been tramways and railways.

Early rail zig zags include:

  • 187x - Lapstone Zig Zag, N S Wales - replaced by tunnel, then by deviation
  • 1869 - Lithgow Zig Zag, N S Wales - replaced by 10 tunnels

N Year Max
Type Link Detail Notes
400 1833 1 in 11.23 IP Rail Bryngwyn incline NWNGR
402 1836 IP Rail Old Moelwyn Tunnel temporary incline IP=Incline Plane
101 1888 1 in 10 ZZ Foot North Wales Narrow Gauge Railways AS
208 2013 1 in 40 ZZ Rail Plas Halt GH
144 1066 1 in 08 ZZ Foot Beddgelert Station FRR
201 1887 1 in 12 ZZ Foot Walks around the Railway AA
301 186_ 1 in 33 ZZ Rail Lapstone Zig Zag ZZ=Zig Zag
202 1869 1 in 33 08 ZZ Rail Lithgow Zig Zag NSW [1]

Raw data[edit]

   were planned. The first were in 1885 when an extension to Caernarfon and a zig-zag line to replace the Bryngwyn incline were proposed. Neither was built but
   3 KB (409 words) - 02:16, 15 August 2015
   a distance of 6 miles 19chains (10km) from Porthmadog. It is located at Zig-zag Crossing immediately to the north of Tyler's Curve above Plas Tan y Bwlch
   3 KB (490 words) - 02:14, 15 August 2015
   Goat Hotel. Between the car park and the station there is a long tarmac ‘zig-zag’ sloping path which is relatively steep but usable by wheelchairs. The slope
   20 KB (3,157 words) - 02:17, 15 August 2015
   Glan-yr-Afon. In 800m once past Plas Glan-yr-Afon and Ty-gwyn, turn left onto a zig-zag path towards Bontnewydd. On entering the village (Dol Pandy farm) turn left
   32 KB (5,059 words) - 02:20, 15 August 2015


Inclines worked by ropes are another way of avoiding tunnels, until traffic increases so much as to make that tunnel inconvenient.

Incline planes and zig zags[edit]

Just in case you miss it…[edit]

… I've written on your Talk page about switchbacks, inclines and categories. (I won't mind if you delete this notice when you've seen it; a user's talk page is the usual place to address him or her.) --IP (talk) 15:04, 15 August 2015 (UTC)


An abbreviation for

  • "Questions Now Needing Answers", or
  • "Quibbles Now Needing Alterations",
  • might be
  • QNNA - few false search matches in either Wikipedia or Festipedia
  • [QNNA]
  • QNNA - a link
  • [[[QNNA]]] - a link with visible square brackets, except that it doesn't work
  • (QNNA)
  • (QNNA)
  • (QNNA) has a converse meaning compared to (sic).
  • FarleyBrook (talk) 04:34, 18 August 2015 (UTC)



K Year Engine Tons Load
Wagons Tons Gradient
Comments Ref
A 1869 Little Wonder 19.5 x y 120 1.25 15 900 [2]
C aaaa s t 50 1.00 000

Narrow Gauge Railways[edit]

  • FR Co. at Minffordd (1ft 1¼in gauge)
  • Corris Railway at Machynlleth (2ft 3in gauge)
  • Talyllyn Railway at Tywyn (2ft 3in gauge)
  • Plynlimon and Hafan Tramway at Llanfihangel (later Llandre) (2ft 3in gauge)
  • Kerry Tramway at Kerry, Powys (2ft 0in gauge)
  • Vale of Rheidol Railway* at Aberystwyth (1 ft 11¾ in gauge)
  • Welshpool & Llanfair Light Railway* at Welshpool (2ft 6in gauge)

See: Feeder lines

See also[edit]

Template:Zig Zags and Inclined Planes


  1. ^
  2. ^ "THE FAIRLIE ENGINES AND STEAM CARRIAGES". Hamilton Spectator and Grange District Advertiser (South Melbourne, Vic. : 1860 - 1870). South Melbourne, Vic.: National Library of Australia. 4 December 1869. p. 1 Supplement: SUPPLEMENT TO THE HAMILTON SPECTATOR. Retrieved 9 October 2015.
  3. ^

External links[edit]


Accident Record[edit]


Day Log[edit]


See also[edit]


  1. ^ "WELSH SPEAKING RAILWAY SERVANTS". Newcastle Morning Herald and Miners' Advocate (NSW : 1876 - 1954) . NSW: National Library of Australia. 12 January 1895. p. 9. Retrieved 29 November 2015.
  2. ^ "FESTINIOG - The Aberystwith Observer". David Jenkins. 1879-04-26. Retrieved 2017-03-17.