South African Class 15 4-8-2

{{Short description|1914 design of steam locomotive}} {{Use dmy dates|date=December 2013}} {{Use South African English|date=December 2013}} {{Infobox locomotive | name = South African Class 15 & 15AR 4-8-2 | image = SAR Class 15AR 1566 Port Elizabeth 030478.jpg | alt = | caption = No. 1566, reboilered and reclassified to Class 15AR, Port Elizabeth, 3 April 1978 | hatnote = ♠ Class 15 as built with a Belpaire firebox<br>{{font color|red|♥}} Class 15AR rebuilt with a Watson Standard boiler<br>{{font color|blue|♣}} Steel firebox - {{font color|magenta|♦}} Copper firebox | powertype = Steam | designer = [[South African Railways]]<br>(D.A. Hendrie) | builder = [[North British Locomotive Company]] | ordernumber = | serialnumber = 20364-20373 | buildmodel = Class 15 | builddate = 1914 | totalproduction = 10 | rebuilder = | rebuilddate = | numberrebuilt = | whytetype = [[4-8-2]] (Mountain) | uicclass = 2'D1'h2 | driver = 2nd coupled axle | gauge = {{Track gauge|Cape|allk=on}} | leadingdiameter = {{convert|28+1/2|in|mm|0|abbr=on}} | coupleddiameter = {{convert|57|in|mm|0|abbr=on}} | trailingdiameter = {{convert|33|in|mm|0|abbr=on}} | tenderdiameter = {{convert|34|in|mm|0|abbr=on}} | minimumcurve = | wheelbase = {{convert|60|ft|6|in|mm|0|abbr=on}} | engine total = {{convert|33|ft|8|in|mm|0|abbr=on}} | leading = {{convert|6|ft|2|in|mm|0|abbr=on}} | coupled = {{convert|15|ft|mm|0|abbr=on}} | trailing = | tender total = {{convert|16|ft|9|in|mm|0|abbr=on}} | tenderbogie = {{convert|4|ft|7|in|mm|0|abbr=on}} | pivotcentres = | wheelspacing = | length = | over couplers = {{convert|68|ft|10+3/4|in|mm|0|abbr=on}} | over bufferbeams= | width = | height = ♠ {{convert|12|ft|10|in|mm|0|abbr=on}}<br>{{font color|red|♥}} {{convert|12|ft|11+3/4|in|mm|0|abbr=on}} | frametype = [[Locomotive frame#Plate frames|Plate]] | axleload = ♠{{font color|red|♥}}{{font color|blue|♣}} {{convert|16|lt|11|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|16|lt|14|lcwt|kg|sigfig=4|abbr=on}} | leadingbogie/pony= ♠ {{convert|15|lt|14|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|blue|♣}} {{convert|16|lt|1|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|16|lt|6|lcwt|kg|sigfig=4|abbr=on}} | coupled all = | coupled 1 = ♠{{font color|red|♥}}{{font color|blue|♣}} {{convert|16|lt|10|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|16|lt|13|lcwt|kg|sigfig=4|abbr=on}} | coupled 2 = ♠ {{convert|16|lt|10|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|blue|♣}} {{convert|16|lt|9|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|16|lt|6|lcwt|kg|sigfig=4|abbr=on}} | coupled 3 = ♠{{font color|red|♥}}{{font color|blue|♣}} {{convert|16|lt|11|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|16|lt|14|lcwt|kg|sigfig=4|abbr=on}} | coupled 4 = ♠{{font color|red|♥}}{{font color|blue|♣}} {{convert|16|lt|9|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|16|lt|11|lcwt|kg|sigfig=4|abbr=on}} | coupled 5 = | coupled 6 = | coupled 7 = | coupled 8 = | trail bogie/pony= ♠{{font color|red|♥}}{{font color|blue|♣}} {{convert|12|lt|6|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|12|lt|7|lcwt|kg|sigfig=4|abbr=on}} | tenderbogieload = '''Bogie 1:''' {{convert|27|lt|10|lcwt|kg|sigfig=4|abbr=on}}<br>'''Bogie 2:''' {{convert|23|lt|11|lcwt|kg|sigfig=4|abbr=on}} | tenderaxle = {{convert|13|lt|15|lcwt|kg|sigfig=4|abbr=on}} | weightondrivers = ♠ {{convert|66|lt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|blue|♣}} {{convert|65|lt|19|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|66|lt|4|lcwt|kg|sigfig=4|abbr=on}} | locoweight = ♠ {{convert|94|lt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|blue|♣}} {{convert|94|lt|6|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|94|lt|17|lcwt|kg|sigfig=4|abbr=on}} | tenderweight = {{convert|51|lt|1|lcwt|kg|sigfig=4|abbr=on}} | locotenderweight = ♠ {{convert|145|lt|1|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|blue|♣}} {{convert|145|lt|7|lcwt|kg|sigfig=4|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|145|lt|18|lcwt|kg|sigfig=4|abbr=on}} | tendertype = [[South African type MP1 tender|MP1 (2-axle bogies)]]<br>[[South African type MP tender|MP]], MP1, [[South African type MR tender|MR]], [[South African type MS tender|MS]], [[South African type MT tender|MT]], [[South African type MT1 tender|MT1]], [[South African type MT2 tender|MT2]], [[South African type MX tender|MX]], [[South African type MY tender|MY]], [[South African type MY1 tender|MY1]] permitted | fueltype = Coal | fuelcap = {{convert|10|lt|t|1|abbr=on}} | watercap = {{convert|4250|impgal|L|sigfig=3|abbr=on}} | tendercap = | sandcap = | fireboxtype = ♠ [[Belpaire firebox|Belpaire]] - {{font color|red|♥}} Round-top | firearea = ♠ {{convert|40|sqft|m2|abbr=on}}<br>{{font color|red|♥}} {{convert|37|sqft|m2|abbr=on}} | boiler = [[South African locomotive numbering and classification#Watson Standard boilers|Watson Standard no. 2A]] | boilertype = | pitch = ♠ {{convert|7|ft|9|in|mm|0|abbr=on}}<br>{{font color|red|♥}} {{convert|8|ft|1/2|in|mm|0|abbr=on}} | diameterinside = ♠ {{convert|5|ft|4+5/8|in|mm|0|abbr=on}}<br>{{font color|red|♥}} {{convert|5|ft|7+1/2|in|mm|0|abbr=on}} | lengthinside = ♠ {{convert|21|ft|9|in|mm|0|abbr=on}}<br>{{font color|red|♥}}{{font color|blue|♣}} {{convert|21|ft|8|in|mm|0|abbr=on}}<br>{{font color|red|♥}}{{font color|magenta|♦}} {{convert|21|ft|7+5/8|in|mm|0|abbr=on}} | smalltubediameter= ♠ '''131:''' {{convert|2+1/4|in|mm|0|abbr=on}}<br>{{font color|red|♥}} '''87:''' {{convert|2+1/2|in|mm|0|abbr=on}} | largetubediameter= ♠ '''24:''' {{convert|5+1/2|in|mm|0|abbr=on}}<br>{{font color|red|♥}} '''30:''' {{convert|5+1/2|in|mm|0|abbr=on}} | boilerpressure = ♠ {{convert|185|psi|kPa|0|abbr=on}}<br>{{font color|red|♥}} {{convert|190|psi|kPa|0|abbr=on}} | safetyvalvetype = ♠ [[Safety valve#Ramsbottom safety valves|Ramsbottom]] - {{font color|red|♥}} [[Safety valve#"Pop" valves|Pop]] | feedwaterheater = | totalsurface = ♠ {{convert|2578|sqft|m2|abbr=on}}<br>{{font color|red|♥}} {{convert|2313|sqft|m2|abbr=on}} | tubearea = ♠ {{convert|2423|sqft|m2|abbr=on}}<br>{{font color|red|♥}} {{convert|2171|sqft|m2|abbr=on}} | fluearea = | tubesandflues = | fireboxarea = ♠ {{convert|155|sqft|m2|abbr=on}}<br>{{font color|red|♥}} {{convert|142|sqft|m2|abbr=on}} | superheatertype = | superheaterarea = ♠ {{convert|601|sqft|m2|abbr=on}}<br>{{font color|red|♥}} {{convert|537|sqft|m2|abbr=on}} | generator = | cylindercount = Two | cylindersize = {{convert|22|in|mm|0|abbr=on}} bore<br>{{convert|28|in|mm|0|abbr=on}} stroke | frontcylindersize= | rearcylindersize = | hpcylindersize = | lpcylindersize = | valvegear = [[Walschaerts valve gear|Walschaerts]] | valvetype = [[Piston valve (steam engine)|Piston]] | valvetravel = | valvelap = | valvelead = | transmission = | trainheating = | locobrakes = | trainbrakes = | safety = | coupling = [[Railway coupling#Johnston coupler|Johnston link-and-pin]]<br>[[Janney coupler|AAR knuckle]] (1930s) | maxspeed = | poweroutput = | tractiveeffort = ♠ {{convert|32990|lbf|kN|abbr=on}} @ 75%<br>{{font color|red|♥}} {{convert|33880|lbf|kN|abbr=on}} @ 75% | factorofadhesion = | locobrakeforce = | operator = South African Railways<br>[[Eswatini Railways|Swaziland Railway]] | operatorclass = Class 15 & 15AR | powerclass = | numinclass = 10 | fleetnumbers = 1561-1570 | officialname = | nicknames = | axleloadclass = | locale = | deliverydate = 1914 | firstrundate = 1914 | lastrundate = | withdrawndate = 1980s | preservedunits = | restoredate = | scrapdate = | currentowner = | disposition = | notes = The leading coupled axle had flangeless wheels }}

The '''South African Railways Class 15 4-8-2''' of 1914 was a steam locomotive.

In 1914, the South African Railways placed ten Class 15 steam locomotives with a {{nowrap|[[4-8-2]]}} Mountain type wheel arrangement in service.<ref name="Holland 2">{{Holland-Vol 2|page=26}}</ref><ref name="SAR&H Jul 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 (Continued).'' South African Railways and Harbours Magazine, July 1945. p. 516.</ref><ref name="Paxton-Bourne">{{Paxton-Bourne|pages=10-11, 59-60}}</ref>

==Manufacturer== D.A. Hendrie, Chief Mechanical Engineer (CME) of the South African Railways (SAR), commenced with design work on the Class 15 in 1913. It was intended as a mixed-traffic locomotive for use in the [[Orange Free State (province)|Orange Free State]], where gradients and curvature were less severe than on the coastal sections. The locomotive was similar in general layout to the [[South African Class 12 4-8-2|Classes 12]] and [[South African Class 14 4-8-2|14]], but with larger {{convert|57|in|mm|0|abbr=off}} coupled wheels. Ten locomotives were built by the [[North British Locomotive Company]] (NBL) and delivered in February and March 1914, numbered in the range from 1561 to 1570.<ref name="Holland 2"/><ref name="SAR&H Jul 1945"/><ref name="NBL">North British Locomotive Company works list, compiled by Austrian locomotive historian Bernhard Schmeiser</ref>

==Characteristics== The engines had plate frames, [[Walschaerts valve gear]], [[Belpaire firebox]]es without combustion chambers and were superheated. They were delivered with [[South African type MP1 tender|Type MP1 tenders]] which had a coal capacity of {{convert|10|lt|t|1|abbr=off}} and a water capacity of {{convert|4250|impgal|L|sigfig=3|abbr=off}}.<ref name="Holland 2"/><ref name="Paxton-Bourne"/><ref name="Diagram-book 1">South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). ''Locomotive Diagram Book/Lokomotiefdiagramboek, 3'6" Gauge/Spoorwydte''. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. p. 43.</ref><ref name="Diagram-book 2">South African Railways & Harbours/Suid Afrikaanse Spoorweë en Hawens (15 Aug 1941). ''Locomotive Diagram Book/Lokomotiefdiagramboek, 2'0" & 3'6" Gauge/Spoorwydte, Steam Locomotives/Stoomlokomotiewe''. SAR/SAS Mechanical Department/Werktuigkundige Dept. Drawing Office/Tekenkantoor, Pretoria. pp. 6a-7a, 41, 43.</ref>

[[File:D.A. Hendrie.jpg|thumb|left|150px|D.A. Hendrie]] To reduce the weight on the trailing wheels, steel fireboxes were originally used instead of copper since the water quality in the Free State was considered suitable for this metal. Some locomotives in Natal had been fitted with steel fireboxes years previously and the results were fairly good, but wherever water supplies were of poor quality, steel fireboxes gave a lot of trouble and necessitated the introduction of water treatment plants to prevent corrosion.<ref name="Holland 2"/><ref name="SAR&H Jul 1945"/><ref name="Paxton-Bourne"/><ref name="Durrant">{{Durrant-Twilight|pages=83-84}}</ref>

This reintroduction of steel fireboxes eventually led to its widespread use on all the larger locomotive types, but it also forced the SAR to adopt locomotive water treatment as a general policy. There was no settled policy on water treatment for some years, but engines with copper fireboxes were used mainly in areas where the water was not of good quality. Hendrie followed a conservative policy in this respect and steel fireboxes were only to be fitted in large numbers by his successor, Colonel F.R. Collins DSO.<ref name="SAR&H Jul 1945"/>

In the case of the Class 15, it was still early days for water treatment and enough trouble was experienced to result in their steel fireboxes being replaced with copper fireboxes. The locomotive's one flaw was excessively long fire tubes. On later models like the [[South African Class 15A 4-8-2|Class 15A]], Hendrie improved the boiler by adding a combustion chamber, which shortened the distance between tube plates from {{convert|21|ft|9|in|mm|0|abbr=off}} to {{convert|19|ft|mm|0|abbr=off}}.<ref name="Holland 2"/><ref name="SAR&H Jul 1945"/>

==Watson Standard boilers== During the 1930s, many serving locomotives were reboilered with a standard boiler type designed by A.G. Watson, CME of the SAR from 1929 to 1936, as part of his standardisation policy. Such Watson Standard reboilered locomotives were reclassified by adding an "R" suffix to their classification.<ref name="Paxton-Bourne"/><ref name="Diagram-book 1"/><ref name="Diagram-book 2"/>

When all ten Class 15 locomotives were reboilered with [[South African locomotive numbering and classification#Watson Standard boilers|Watson Standard no. 2A]] boilers, they were reclassified to Class 15AR since the only differences between the as-delivered Class 15 and the Class 15A lay in the length of their boilers and whether they were built with or without combustion chambers. In the process, the locomotives were also equipped with Watson cabs with their distinctive slanted fronts, compared to the conventional vertical fronts of their original cabs. During reboilering, some were equipped with steel and others with copper fireboxes.<ref name="SAR&H Jul 1945"/><ref name="Paxton-Bourne"/>

Their original Belpaire boilers were fitted with [[Safety valve#Ramsbottom safety valves|Ramsbottom safety valves]], while the Watson Standard boiler was fitted with [[Safety valve#"Pop" valves|Pop safety valves]]. Another obvious difference between an original and a Watson Standard reboilered locomotive is usually a rectangular regulator cover, just to the rear of the chimney on the reboilered locomotive. In the case of the Classes 15 and 15AR, two even more obvious differences are the Watson cab and the absence of the Belpaire firebox hump between the cab and boiler on the reboilered locomotives.<ref name="Diagram-book 1"/><ref name="Diagram-book 2"/>

==Service== The Class 15 was placed in service in the Orange Free State, shedded at [[Bloemfontein]]. After reboilering and reclassification, they became part of the much larger Class 15AR fleet and saw service widely throughout the country, getting used in every kind of role from dock shunting to mainline passenger work.<ref name="Holland 2"/><ref name="Paxton-Bourne"/>

The Cape Northern examples were scattered between [[De Aar]], [[Kimberley, Northern Cape|Kimberley]] and [[Klerksdorp]]. The Cape Midland was a major user of the Class, with locomotives shedded at Sydenham in [[Port Elizabeth]], Klipplaat, [[Graaff Reinet]] and [[Noupoort]]. The Class 15AR also worked the suburban services between Port Elizabeth and [[Uitenhage]] until they were replaced by diesel power.<ref name="Durrant"/>

Near the end of their service lives in the early 1980s, they were all relegated to shunting work at centres all around the country, except for some which were hired out to [[Eswatini|Swaziland]] and which were still employed in mainline service on the [[Eswatini Railways|Swaziland Railway]] until they were also eventually replaced by diesel traction and retired.<ref name="Durrant"/>

==Preservation== {| class="wikitable" |- ! Number !! Works nmr !! THF / Private !! Leaselend / Owner !! Current Location !! Outside South Africa !! ? |- | 1791 || || THF || || Bloemfontein Locomotive Depot || || |- | 1970 || || Private || Greg Mc.Lennan || || || |- | || || || || || || |- | 1798 || || THF || || Queenstown Locomotive Depot || || |- | 1820 || || THF || || Krugersdorp Locomotive Depot || || |- | 1840 || || THF || || Klipplaat Locomotive Depot || || |- | 1850 || || THF || || Bloemfontein Locomotive Depot || || |- | 1963 || || Private || Railway Society of South Africa || || || |- | 1966 || || THF || || Queenstown Locomotive Depot || || |- | 2012 || || THF || || Queenstown Locomotive Depot || || |- | 2016 || || Private || Municipality || Queenstown Casino || || |- | 2093 || || THF || || Queenstown Locomotive Depot || || |- | 2100 || || THF || || Queenstown Locomotive Depot || || |}

==Illustration== The main picture, showing the reboilered and reclassified Class 15AR no. 1566 at Port Elizabeth, and the following illustrate the Class before and after modification. <gallery mode=packed heights="200px"> File:SAR Class 15AR 1568 Midlandia 010479.jpg|Class 15AR No. 1568 with a modified [[South African type MP1 tender|Type MP1 tender]], Midlandia, 1979 File:Class 15 no. 1561.jpg|No. 1561 as built, with an as-delivered [[South African type MP1 tender|Type MP1 tender]] and Belpaire firebox, c. 1914 </gallery>

==References== {{Commonscat|South African Class 15 (4-8-2)|South African Class 15 4-8-2|position=left}} {{Reflist|30em}} {{Locomotives of South Africa}} {{Steam locomotive tenders}}

[[Category:Steam locomotives of South Africa|1810]] [[Category:D.A. Hendrie locomotives|1810]] [[Category:Watson Standard no. 2A|1810]] [[Category:4-8-2 locomotives]] [[Category:2D1 locomotives]] [[Category:NBL locomotives]] [[Category:Cape gauge railway locomotives]] [[Category:Railway locomotives introduced in 1914]] [[Category:1914 in South Africa]] [[Category:Scrapped locomotives]]