Rail gauge

From Festipedia, hosted by the FR Heritage Group

Rail gauge is the distance between the rails, measured between the insides of the heads slightly below the top, as the rail head is slightly rounded, both when new and when worn.

The width of the head of a rail increases as the weight of the rail increases, so it would be problematic to measure the gauge between the centres of the heads of the rail, as formerly in Italy. The Blaenau quarry gauge, on metal bars, was possibly 2ft centre-to-centre; this may have been followed by the FR. At Llanberis this is certainly the case, but the railway was 1ft 10.75in gauge (it is now FR standard). It is an intriguing archaeological finding that the rutways of Roman roads, measured both in Britain and in Italy, are consistently 4ft 10ins centre to centre (or 4ft 8in between the inside edges).[1] That is also the pace of a Roman legionary, left foot to left foot, at 4.855ft; a thousand of these at 4855ft is miles passuum, a Roman mile. The Stockton & Darlington Ry of 1825 was 4ft 8in - the extra half-inch of the standard gauge seems to have been added around 1830 to allow more play for the wheels.

Guide to Horse-Drawn Tramroads and Waggonways[edit]

The Discovering Britain's First Railways some but not all the gauges of railways that preceeded "proper" railways such as the Liverpool and Manchester railway.


On the Festiniog Railway, the gauge is nominally 2ft, but the -

  • actual gauge on straights is 1 ft 11½ ins (597 mm)(Dow 2014), and the
  • actual gauge on "sharp" curves is up to 2 ft (610 mm).

In metric terms, the FR gauge is 597mm, but on sharp curves it may increase to 610mm.[2] The wheels have treads wide enough to accommodate these differences.

The complete set of measurements for FR track and wheel-sets is:

Gauge 23½ inches (597 mm)

Back to back wheel measurement 21 inches (533 mm)

Outer rail to check rail gauge 22⅛ inches (562 mm)

Check rail clearance 1⅜ inches (35 mm)

Clearances, wheel to rail ¼ inch (6.35 mm)

Width of tread 3⅛ inches (79 mm)

Thickness of flange 1 inch (25.4 mm)

Gradient of coning 1 in 18

Typical diameter of wheels 18 inches (457 mm)

Inclination of rails 1 in 20 (recent relaying - was nil for chaired and early F/B track - an early reference to using inclined base plates is FRM No. 156 p 468 in 1997.)

Depth of flange 15/16ths (23.8 mm)

Source: Dow A 2014 Appendix F.

Gauge widening[edit]

Gauge widening is only required on sharp curves. The sharpest on the FR is Tyler's Curve of 2.4 chains (now 40m) radius. At what radius does a sharp gauge cease to be "sharp"?

Other Railway Gauges[edit]

The Gauge Commission of 1845 chose the Stephenson gauge rather than the broader Brunel gauge, but didn't concern itself with gauges narrow than Stephenson's. As a result, narrow gauge (NG) lines, of which the Festiniog Railway was a pioneer, adopted a dog's breakfast of gauges. FR was not affected by the 1846 Act, being incorporated and opened before it came into force. That is why the FR was able to have a passenger service in 1865.

Other UK railway gauges are as follows:

Railway Region Gauge ft.in. Gauge mm Earliest
Romney Hythe & Dymchurch Railway UK Kent 15⅛ inches (0384 mm) 1927 AA [3]
Talyllyn Railway Wales 27 inches (0686 mm) 1866 CC [4]
Welshpool & Llanfair Light Railway Wales 30 inches (0762 mm) 1903 FF [5]
Isle of Man Railway I of Man 36 inches (0914 mm) 1873 JJ [6]
Glasgow Subway Scotland 48 inches (1220 mm) 1896 MM [7]
London Transport UK London 56⅜ inches (1432 mm but 1435 mm
on ballasted flat
bottom track)
1863 PP
Network Rail UK 56½ inches (1435 mm) 1830 RR
Northern Ireland Railways
D&DR 5ft 2in
UR 6ft 2in
D&KR 4ft 8½in
NI 63 inches (1600 mm)
SS [8] Converted to
Irish Gauge.
Broad Gauge UK GWR 84¼ inches (2140 mm) 1838 TT [9]
Vale of Rheidol Railway Wales 23¾ inches (0603 mm) 1902 UU [10]
Corris Railway Wales 27 inches (0686 mm) 1859 VV [11]
Welsh Highland Railway Wales 23½ inches (0597 mm) 1923 WW [12]
Croesor Tramway Wales 24 inches (0610 mm) 1864 XX [13] Horse drawn
Penrhyn Quarry Railway Wales 22¾ inches (578 mm) 1798 XA [14]
Snowdon Mountain Railway Wales 31½ inches (0800 mm) 1896 XD [15] Abt rack.
Snaefell Mountain Railway I of Man 42 inches (1067 mm) 1895 XG [16] Fell "rack".
Bala Lake Railway Wales 24 inches (0610 mm) 1972 XJ [17]
Brecon Mountain Railway Wales 23¾ inches (0603 mm) 1980 XK [18]
Fairbourne Railway Wales 12¼ inches (0311 mm) 1980 XL [19]
Llanberis Lake Railway Wales 23¾ inches (0603 mm) 1971 XM [20]
Festiniog Railway Wales 23½ inches (0597 mm) 1836 XP [21]
Manx Electric Railway I of Man 36 inches (0915 mm) 1893 XQ [22]
Padarn Railway 48 inches 1843 XR [23]


External Links[edit]


Newspaper articles in far off N S Wales reported, or misreported, even more gauges for the Festiniog Railway than the FR ever had, including:

Gauge Tags 1 Tags 2 Comment Earliest
1ft11in 2 4 Incorrect 1873 FF [1]
1ft11¼in 1 9 Normal
Unwidened Gauge
1873 DD
1ft11½in 9 42 Widened Gauge
on "Sharp" Curves
Mistakenly assumed to be "Normal" gauge
1870 K
1ft11¾in 2 3 Incorrect 1869 ZZ
2ft 0in 14 87 Rounded Gauge 1864 PP [2]
2ft 1in 1 1 Rounded Gauge with muddled
widening on sharp curves.
1870 QQ [3]
2ft 6in 3 11 Incorrect 1867 EE [4] Ample. [5]
2ft 9in 1 2 Incorrect 1871 TT [6][7]
3ft 0in 1 Proposed for Light Rail TV
First Railway QLD 1865 SS
Pre-railway TAS 1869 TW [8]
5ft 3in First Railway TAS (BG) TX ; so as to share designs with Victoria
3ft 6in Second Railway TAS (NG) 1876 UU ; probably influenced by Pihl and Queensland
2ft 0in Third Railway TAS (TG) UX ; possibly influenced by Fairlie and FR ; mountainous terrain.
3ft 6in First Railway WA 1879 HH
56 Fairlie locomotive 1869 LL
66 238 Festiniog Railway 1866 PP
22 Ffestinog (spelling) 1853 F1
920 1281 Festiniog (spelling) 1840 F0
10 Festiniog Quarry (slate) 1850 FQ
2ft 3in 2 Talyllyn Railway 1951 TT [9]
  • Note: Tags = Number of Tagged NLA Newspaper Articles ; this is a work in progress.
  • Note: NLA=National Library of Australia.
  • Note: (QNNA) "Sharp" curve means less than ______ chains radius.
  • Note: The dates of the "First Railways in" are to help tell if the NG FR influenced the selection of Narrow Gauge (NG) in those colonies.
  • Note: Number of tags means number counted "so far". Needs to be manually updated from time to time.
  • Note: It is difficult to search for "1ft 11 1/2", etc. These strings need to be tagged/bookmarked whenever you come across them.


The construction of the Mount Zeehan Tramway Company Limited line, in Tasmania, quoted the Festiniog Railway as its exemplar, but nonetheless rounded the gauge from 1ft 11½in to 2ft 0in. [10]


A number of articles in far away Australian newspapers are quite praiseworthy the narrow gauge of the Festiniog Railway, and the associated Fairlie Locomotive system, including:

  • famous
  • celebrated
  • remarkable
  • extraordinary.
  • oft-told

The following terms are a bit ambiguous:

Some sources cast doubt on the relevance of the Festiniog system, probably for reasons including:

  • heavy traffic, several trains per day; hard not to make money
  • freight rates higher per mile for narrow gauge than for standard gauge; hard not to make money ; politically unsuitable for government railway.
  • heavy traffic mostly goes downhill with continuous gradients ; would other Horse railways be so fortunate?
  • transhipment is mainly to ships at Portmadoc, and relatively little transhipment between narrow gauge and standard gauge.
  • very low speeds on FR:
    • even on straight track
    • especially on minimum radius curves
    • imagine a slow Festiniog-gauge line hundreds if not thousands of miles long.

In the event, the Fairlie's Patent system did not catch on in far off Australia, being supplanted by the superior Garratt locomotive pioneered by K1.

Frequency counts of the above yet to be determined.

See also[edit]


  1. ^ http://nla.gov.au/nla.news-article13249470
  2. ^ "COUNTRY NEWS". The Argus (Melbourne, Vic. : 1848 - 1957). Melbourne, Vic.: National Library of Australia. 29 February 1864. p. 7. Retrieved 19 September 2015.
  3. ^ "THE FESTINIOG RAILWAY". The Brisbane Courier (Qld. : 1864 - 1933). Qld.: National Library of Australia. 12 January 1870. p. 4. Retrieved 29 September 2015.
  4. ^ "RAILWAY EXTENSION". South Australian Register (Adelaide, SA : 1839 - 1900). Adelaide, SA: National Library of Australia. 27 November 1867. p. 2. Retrieved 26 August 2015.
  5. ^ "THE FESTINIOG RAILWAY". The Hay Standard and Advertiser for Balranald, Wentworth, Maude...(Hay, NSW : 1871 - 1873; 1880 - 1881; 1890 - 1900). Hay, NSW: National Library of Australia. 16 April 1873. p. 2. Retrieved 4 October 2015.
  6. ^ "MUNDOORAN". Australian Town and Country Journal (Sydney, NSW : 1870 - 1907). Sydney, NSW: National Library of Australia. 25 November 1871. p. 7. Retrieved 14 September 2015.
  7. ^ NLA
  8. ^ "RAILWAYS IN TASMANIA". Launceston Examiner (Tas. : 1842 - 1899). Tas.: National Library of Australia. 7 December 1869. p. 1 Supplement: Supplement to the Launceston Examiner. Retrieved 26 October 2015.
  9. ^ "The Little Old Railway". The Sunday Herald (Sydney, NSW : 1949 - 1953). Sydney, NSW: National Library of Australia. 18 February 1951. p. 11 Supplement: Sunday Herald Features. Retrieved 28 October 2015.
  10. ^ "Advertising". South Australian Register (Adelaide, SA : 1839 - 1900). Adelaide, SA: National Library of Australia. 28 July 1888. p. 2. Retrieved 30 November 2015.
  11. ^ http://trove.nla.gov.au/newspaper/article/174260867

Dow A (2014) The Railway, British track since 1804, Pen & Sword, 47 Church Street, Barnsley, South Yorkshire, S70 2AS, UK

External links[edit]