South African Class Experimental 4 2-8-2

{{Short description|1903 design of steam locomotive}}

{{About|one of two different Cape Government Railways locomotive types to be designated "9th Class"|the other|South African Class Experimental 5 2-8-2}}

{{Use dmy dates|date=March 2025}}

{{Use South African English|date=October 2013}}

{{Infobox locomotive

| name = CGR 9th Class 2-8-2 1903
{{nowrap|South African Class Experimental 4 2-8-2}}

| image = SAR Class Exp 4 911 (2-8-2) CGR 9th Class 806.jpg

| alt =

| caption = CGR 9th Class no. 806, c. 1911
SAR Class Experimental 4 no. 911

| hatnote =

| powertype = Steam

| designer = Cape Government Railways
(H.M. Beatty)

| builder = Kitson and Company

| ordernumber =

| serialnumber = 4195-4196

| buildmodel = CGR 9th Class

| builddate = 1903

| totalproduction = 2

| rebuilder =

| rebuilddate =

| numberrebuilt =

| whytetype = 2-8-2 (Mikado)

| uicclass = 1'D1'n2

| driver = 3rd coupled axle

| gauge = {{Track gauge|Cape|allk=on}}

| leadingdiameter = {{convert|28+1/2|in|mm|0|abbr=on}}

| coupleddiameter = {{convert|48|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
{{convert|34|in|mm|0|abbr=on}} retyred

| minimumcurve =

| wheelbase = {{convert|50|ft|7+1/4|in|mm|0|abbr=on}}

| engine total = {{convert|26|ft|9|in|mm|0|abbr=on}}

| leading =

| coupled = {{convert|13|ft|1|in|mm|0|abbr=on}}

| trailing =

| tender total = {{convert|14|ft|7|in|mm|0|abbr=on}}

| tenderbogie = {{convert|4|ft|7|in|mm|0|abbr=on}}

| wheelspacing = 1-2: {{convert|4|ft|7|in|mm|0|abbr=on}}
2-3: {{convert|4|ft|3|in|mm|0|abbr=on}}
3-4: {{convert|4|ft|3|in|mm|0|abbr=on}}

| length =

| over couplers = {{convert|58|ft|5+3/4|in|mm|0|abbr=on}}

| over bufferbeams =

| pivotcentres =

| width =

| height = {{convert|12|ft|10|in|mm|0|abbr=on}}

| frametype = Bar

| axleload = {{convert|12|lt|16|lcwt|kg|sigfig=4|abbr=on}}

| leadingbogie/pony= {{convert|5|lt|5|lcwt|kg|sigfig=4|abbr=on}}

| coupled all =

| coupled 1 = {{convert|12|lt|6|lcwt|kg|sigfig=4|abbr=on}}

| coupled 2 = {{convert|11|lt|16|lcwt|kg|sigfig=4|abbr=on}}

| coupled 3 = {{convert|12|lt|kg|sigfig=4|abbr=on}}

| coupled 4 = {{convert|12|lt|16|lcwt|kg|sigfig=4|abbr=on}}

| coupled 5 =

| coupled 6 =

| coupled 7 =

| coupled 8 =

| trail bogie/pony = {{convert|10|lt|4|lcwt|kg|sigfig=4|abbr=on}}

| tenderbogieload =

| tenderaxle = {{convert|9|lt|4|lcwt|1|qtr|kg|sigfig=4|abbr=on}} av.

| weightondrivers = {{convert|48|lt|18|lcwt|kg|sigfig=4|abbr=on}}

| locoweight = {{convert|64|lt|7|lcwt|kg|sigfig=4|abbr=on}}

| tenderweight = {{convert|36|lt|18|lcwt|kg|sigfig=4|abbr=on}}

| locotenderweight = {{convert|101|lt|5|lcwt|kg|sigfig=4|abbr=on}}

| tendertype = XE1 (2-axle bogies)

| fueltype = Coal

| fuelcap = {{convert|6|lt|t|1|abbr=on}}

| watercap = {{convert|2855|impgal|L|abbr=on}}

| tendercap =

| sandcap =

| boiler =

| pitch = {{convert|7|ft|1|in|mm|0|abbr=on}}

| boilertype =

| diameterinside = {{convert|4|ft|10+3/4|in|mm|0|abbr=on}}

| lengthinside = {{convert|14|ft|10+1/8|in|mm|0|abbr=on}}

| smalltubediameter= 159: {{convert|2+1/4|in|mm|0|abbr=on}}

| largetubediameter=

| fireboxtype = Round-top

| boilerpressure = {{convert|180|psi|kPa|0|abbr=on}}

| safetyvalvetype = Ramsbottom

| feedwaterheater =

| firearea = {{convert|26.75|sqft|m2|abbr=on}}

| totalsurface = {{convert|1508.3|sqft|m2|abbr=on}}

| tubearea = {{convert|1391|sqft|m2|abbr=on}}

| fluearea =

| tubesandflues =

| fireboxarea = {{convert|117.3|sqft|m2|abbr=on}}

| superheatertype =

| superheaterarea =

| cylindercount = Two

| cylindersize = {{convert|19|in|mm|0|abbr=on}} bore
{{convert|24|in|mm|0|abbr=on}} stroke

| frontcylindersize=

| rearcylindersize =

| hpcylindersize =

| lpcylindersize =

| valvegear = Stephenson

| valvetype =

| valvetravel =

| valvelap =

| valvelead =

| transmission =

| trainheating =

| locobrakes =

| trainbrakes =

| safety =

| coupling = Johnston link-and-pin

| maxspeed =

| poweroutput =

| tractiveeffort = {{convert|24370|lbf|kN|abbr=on}} @ 75%

| factorofadhesion =

| locobrakeforce =

| operator = Cape Government Railways
South African Railways

| operatorclass = CGR 9th Class
SAR Class Experimental 4

| powerclass =

| numinclass = 2

| fleetnumbers = CGR 805-806, SAR 910-911

| officialname =

| nicknames =

| axleloadclass =

| locale =

| deliverydate = 1903

| firstrundate = 1903

| lastrundate =

| withdrawndate = 1930

| preservedunits =

| restoredate =

| scrapdate =

| currentowner =

| disposition =

| notes = The 2nd & 3rd coupled axles had flangeless wheels

}}

The South African Railways Class Experimental 4 {{nowrap|2-8-2}} of 1903 was a steam locomotive from the pre-Union era in the Cape of Good Hope.

In 1903, the Cape Government Railways placed two 9th Class steam locomotives with a 2-8-2 Mikado type wheel arrangement in service. In 1912, when they were assimilated into the South African Railways, they were renumbered and designated Class Experimental 4.{{Holland-Vol 1|pages=68-69}}Espitalier, T.J.; Day, W.A.J. (1944). The Locomotive in South Africa – A Brief History of Railway Development. Chapter II – The Cape Government Railways (Continued). South African Railways and Harbours Magazine, March 1944. pp. 169–173.Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer’s Office, Pretoria, January 1912, pp. 9, 12, 15, 36 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000){{Paxton-Bourne|page=83}}