{{Short description|1911 design of steam locomotive}} {{Use dmy dates|date=January 2025}} {{Use South African English|date=November 2013}} {{Infobox locomotive | name = CGR Mountain 4-8-2<br>South African Class 4 4-8-2 | image = SAR Class 4 no. 1478.jpg | alt = | caption = SAR Class 4 no. 1478 at Worcester, c. 1930 | hatnote = | powertype = Steam | designer = [[Cape Government Railways]]<br>(H.M. Beatty) | builder = [[North British Locomotive Company]] | ordernumber = | serialnumber = 19242-19243 | buildmodel = CGR 4-8-2 | builddate = 1911 | totalproduction = 2 | rebuilder = | rebuilddate = | numberrebuilt = | whytetype = [[4-8-2]] (Mountain) | uicclass = 2'D1'n2 | driver = 2nd coupled axle | gauge = {{Track gauge|Cape|allk=on}} | leadingdiameter = {{convert|28+1/2|in|mm|0|abbr=on}} | coupleddiameter = {{convert|54|in|mm|0|abbr=on}} | trailingdiameter = {{convert|33|in|mm|0|abbr=on}} | tenderdiameter = {{convert|33+1/2|in|mm|0|abbr=on}} as built<br>{{convert|34|in|mm|0|abbr=on}} retyred | minimumcurve = | wheelbase = {{convert|57|ft|8+3/8|in|mm|0|abbr=on}} | engine total = {{convert|31|ft|11|in|mm|0|abbr=on}} | leading = {{convert|6|ft|2|in|mm|0|abbr=on}} | coupled = {{convert|14|ft|5|in|mm|0|abbr=on}} | trailing = | tender total = {{convert|16|ft|1|in|mm|0|abbr=on}} | tenderbogie = {{convert|4|ft|7|in|mm|0|abbr=on}} | pivotcentres = | wheelspacing = '''1-2:''' {{convert|4|ft|10|in|mm|0|abbr=on}}<br>'''2-3:''' {{convert|4|ft|9|in|mm|0|abbr=on}}<br>'''3-4:''' {{convert|4|ft|10|in|mm|0|abbr=on}} | length = | over couplers = {{convert|65|ft|3/8|in|mm|0|abbr=on}} | over bufferbeams= | width = | height = {{convert|12|ft|10|in|mm|0|abbr=on}} | frametype = [[Locomotive frame#Bar frames|Bar]] | axleload = {{convert|15|lt|kg|sigfig=4|abbr=on}} | leadingbogie/pony= {{convert|11|lt|3|lcwt|kg|sigfig=4|abbr=on}} | coupled all = | coupled 1 = {{convert|14|lt|10|lcwt|kg|sigfig=4|abbr=on}} | coupled 2 = {{convert|14|lt|15|lcwt|kg|sigfig=4|abbr=on}} | coupled 3 = {{convert|14|lt|17|lcwt|kg|sigfig=4|abbr=on}} | coupled 4 = {{convert|15|lt|kg|sigfig=4|abbr=on}} | coupled 5 = | coupled 6 = | coupled 7 = | coupled 8 = | trail bogie/pony= | tenderbogieload = '''Bogie 1:''' {{convert|21|lt|11|lcwt|kg|sigfig=4|abbr=on}}<br>'''Bogie 2:''' {{convert|21|lt|18|lcwt|kg|sigfig=4|abbr=on}} | tenderaxle = {{convert|10|lt|19|lcwt|kg|sigfig=4|abbr=on}} | weightondrivers = {{convert|59|lt|2|lcwt|kg|sigfig=4|abbr=on}} | locoweight = {{convert|82|lt|2|lcwt|kg|sigfig=4|abbr=on}} | tenderweight = {{convert|43|lt|9|lcwt|kg|sigfig=4|abbr=on}} | locotenderweight = {{convert|125|lt|11|lcwt|kg|sigfig=4|abbr=on}} | tendertype = [[South African type XJ tender|XJ (2-axle bogies)]] | fueltype = Coal | fuelcap = {{convert|6|lt|10|lcwt|t|1|abbr=on}} | watercap = {{convert|3500|impgal|L|sigfig=3|abbr=on}} | tendercap = | sandcap = | fireboxtype = Round-top, combustion chamber | firearea = {{convert|37|sqft|m2|abbr=on}} | boiler = | boilertype = | pitch = {{convert|7|ft|6|in|mm|0|abbr=on}} | diameterinside = {{convert|5|ft|6+3/8|in|mm|0|abbr=on}} | lengthinside = {{convert|18|ft|mm|0|abbr=on}} | smalltubediameter= '''201:''' {{convert|2+1/4|in|mm|0|abbr=on}} | largetubediameter= | boilerpressure = {{convert|180|psi|kPa|0|abbr=on}} | safetyvalvetype = [[Safety valve#Ramsbottom safety valves|Ramsbottom]] (No. 850/1477)<br>[[Safety valve#"Pop" valves|Cole's Pop]] (No. 851/1478) | feedwaterheater = | totalsurface = {{convert|2317|sqft|m2|abbr=on}} | tubearea = {{convert|2131|sqft|m2|abbr=on}} | fluearea = | tubesandflues = | fireboxarea = {{convert|186|sqft|m2|abbr=on}} | superheatertype = | superheaterarea = | cylindercount = Two | cylindersize = {{convert|20+1/2|in|mm|0|abbr=on}} bore<br>{{convert|28|in|mm|0|abbr=on}} stroke | frontcylindersize= | rearcylindersize = | hpcylindersize = | lpcylindersize = | valvegear = [[Stephenson valve gear|Stephenson]] | valvetype = [[Slide valve#Murdoch's D slide valve|Murdoch's D slide]] | valvetravel = | valvelap = | valvelead = | transmission = | trainheating = | locobrakes = | trainbrakes = | safety = | coupling = [[Railway coupling#Johnston coupler|Johnston link-and-pin]] | maxspeed = | poweroutput = | tractiveeffort = {{convert|29420|lbf|kN|abbr=on}} @ 75% | factorofadhesion = | locobrakeforce = | operator = Cape Government Railways<br>South African Railways | operatorclass = SAR Class 4 | powerclass = | numinclass = 2 | fleetnumbers = CGR 850-851<br>SAR 1477-1478 | officialname = | nicknames = | axleloadclass = | locale = | deliverydate = 1911 | firstrundate = 1911 | lastrundate = | withdrawndate = 1938 | preservedunits = | restoredate = | scrapdate = | currentowner = | disposition = | notes = The leading coupled axle had flangeless wheels }}

The '''South African Railways Class 4 4-8-2''' of 1911 was a steam locomotive from the pre-[[Union of South Africa|Union]] era in the [[Cape Colony|Cape of Good Hope]].

In 1911, the [[Cape Government Railways]] placed two steam locomotives with a [[4-8-2|{{nowrap|4-8-2}}]] Mountain type wheel arrangement in service. They were renumbered and designated Class 4 when they were assimilated into the South African Railways a year later.<ref name="Holland 2">{{Holland-Vol 2|pages=12–13, 137}}</ref><ref name="SAR&H Apr 1945">Espitalier, T.J.; Day, W.A.J. (1945). ''The Locomotive in South Africa – A Brief History of Railway Development. Chapter VII – South African Railways.'' South African Railways and Harbours Magazine, April 1945. p. 275.</ref><ref name="SAR Renumber">Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 8, 12, 15, 46 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)</ref><ref name="Paxton-Bourne">{{Paxton-Bourne|pages=38–39}}</ref>

==Manufacturer== The first {{nowrap|4-8-2}} Mountain type locomotive of the Cape Government Railways (CGR) was designed as a heavy mixed traffic engine at the Salt River shops by H.M. Beatty, the Chief Locomotive Superintendent of the CGR from 1896 to 1910. Two locomotives were built by the [[North British Locomotive Company]] (NBL) and delivered in March 1911.<ref name="Holland 2"/><ref name="Paxton-Bourne"/><ref name="Durrant">{{Durrant-Twilight|page=13}}</ref>

==Characteristics== The locomotives were a further development of the two experimental locomotives which had been placed in service by the CGR in 1906, the CGR Class 9 {{nowrap|2-8-2}} ([[South African Class Exp 5 2-8-2|SAR Class Experimental 5]]) and the CGR Class 10 {{nowrap|4-8-0}} ([[South African Class Exp 6 4-8-0|SAR Class Experimental 6]]), both built by [[Kitson and Company]].<ref name="Holland 2"/><ref name="Paxton-Bourne"/><ref name="Durrant"/>

[[File:H.M. Beatty.jpg|thumb|left|150px|H.M. Beatty]] The Class 4 locomotives had {{convert|4+1/2|in|mm|0|abbr=off}} thick bar frames, [[Stephenson valve gear]] with flat "D" slide valves arranged above the cylinders, and used saturated steam. The boiler was equipped with a combustion chamber which was carried forward {{convert|2|ft|mm|0|abbr=off}} from the firebox into the boiler barrel, of which the diameter was increased at the hind course to suit. This reduced the distance between the tube plates to {{convert|18|ft|mm|0|abbr=off}} and made them excellent steamers.<ref name="Holland 2"/><ref name="SAR&H Apr 1945"/><ref name="Paxton-Bourne"/>

They were numbered 850 and 851 in the CGR numbering sequence, but were not designated a classification. The two engines were not identical, no. 850 being equipped with the usual [[Ramsbottom safety valve]]s while no. 851 had Cole's muffled type Pop safety valves, both set to open at {{convert|180|psi|kPa|0|abbr=off}} boiler pressure. They were delivered with [[South African type XJ tender|Type XJ]] tenders with a {{convert|6|lt|10|lcwt|t|1|abbr=off}} coal and a {{convert|3500|impgal|L|sigfig=3|abbr=off}} water capacity.<ref name="SAR&H Apr 1945"/><ref name="Paxton-Bourne"/><ref name="Holland 1"/><ref name="NBL">North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser</ref>

==South African Railways== [[File:Cape Colony railways map 1910.svg|thumb|left|Railway network of the Cape Government Railways in 1910, upon the establishment of the Union of South Africa and the South African Railways]] When the [[Union of South Africa]] was established on 31 May 1910, the three Colonial government railways (CGR, [[Natal Government Railways]] and [[Central South African Railways]]) were united under a single administration to control and administer the railways, ports and harbours of the Union. Although the South African Railways and Harbours came into existence in 1910, with Sir William Hoy appointed as its first General Manager, the actual classification and renum&shy;bering of all the rolling stock of the three constituent railways were only implemented with effect from 1 January 1912.<ref name="SAR Renumber"/><ref name="SAR History">''The South African Railways – Historical Survey''. Editor George Hart, Publisher Bill Hart, Sponsored by Dorbyl Ltd., Published c. 1978, p. 25.</ref>

In 1912, these two locomotives were renumbered to 1477 and 1478 and designated Class 4 on the SAR.<ref name="SAR Renumber"/><ref name="Paxton-Bourne"/><ref name="Holland 1">{{Holland-Vol 1|pages=72–75}}</ref>

==Service== Both locomotives were placed in service in the [[Karoo]], working between [[Touws River (town)|Touws River]] and [[Beaufort West]]. In their later years they were stationed at [[Worcester, South Africa|Worcester]], from where they were used extensively on and around the Cape Western system's mainline, working pick-up goods trains to De Doorns in the Hex River valley and on the Mosselbaai line via Robertson.<ref name="Holland 2"/><ref name="Paxton-Bourne"/>

They were withdrawn from service by 1938.<ref name="Paxton-Bourne"/>

==Illustration== The main picture shows SAR no. 1478 at Worcester, c. 1930, with [[Safety valve#"Pop" valves|Cole's Pop safety valves]]. <gallery mode=packed heights="130px"> File:CGR Mountain no. 850.jpg|GCR no. 850, SAR no. 1477, with [[Safety valve#Ramsbottom safety valves|Ramsbottom safety valves]] </gallery>

==References== {{Commons category|South African Class 4 (4-8-2)|South African Class 4 4-8-2|position=left}} {{Reflist}} {{Locomotives of the Cape Government Railways}} {{Locomotives of South Africa}} {{Steam locomotive tenders}}

[[Category:Steam locomotives of South Africa|1260]] [[Category:H.M. Beatty locomotives|1260]] [[Category:4-8-2 locomotives]] [[Category:2D1 locomotives]] [[Category:NBL locomotives]] [[Category:Cape gauge railway locomotives]] [[Category:Railway locomotives introduced in 1911]] [[Category:1911 in South Africa]] [[Category:Scrapped locomotives]]