South African type XM4 tender

{{Infobox steam tender

| name = South African type XM4 tender

| image = Class MF & Type XM4 tender.jpg

| alt =

| imagesize =

| caption = Type XM4 tender on SAR Class MF

| hatnote =

| locomotive = SAR Class MF

| designer = American Locomotive Company

| builder = American Locomotive Company

| worksnumber =

| serialnumber =

| date = 1911

| rebuiltfrom =

| rebuilder =

| rebuilddate =

| rebuiltto =

| wheelarr = 2-axle bogies

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

| length =

| bogies = Diamond frame

| wheeldiameter = {{convert|30|in|mm|0|abbr=on}}

| wheelbase = {{convert|17|ft|10|in|mm|0|abbr=on}}

| bogie = {{convert|5|ft|10|in|mm|0|abbr=on}}

| axleload = {{convert|12|lt|15|lcwt|kg|sigfig=4|abbr=on}} average

| bogieload = {{convert|25|lt|10|lcwt|kg|sigfig=4|abbr=on}} average

| bogie 1 =

| bogie 2 =

| axle 1 =

| axle 2 =

| axle 3 =

| axle 4 =

| axle 5 =

| axle 6 =

| tenderempty = {{convert|51840|lb|kg|abbr=on}}

| tenderworking = {{convert|51|lt|kg|sigfig=4|abbr=on}}

| fueltype = Coal

| fuelcap = {{convert|10|lt|t|1|abbr=on}}

| watercap = {{convert|4000|impgal|L|sigfig=3|abbr=on}}

| stoking = Manual

| coupling = Drawbar & Johnston link-and-pin
Drawbar & AAR knuckle (1930s)

| operator = South African Railways

| fleetnumbers = SAR 1629-1633

| nicknames =

| notes =

}}

The South African type XM4 tender was a steam locomotive tender.

Type XM4 tenders entered service in November 1911, as tenders to the second batch of {{nowrap|2-6-6-2}} Superheated Mallet type steam locomotives which were delivered to the Central South African Railways in that year. These locomotives were designated Class MF on the South African Railways in 1912.{{Holland-Vol 2|pages=16–19}}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.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, 43.

Manufacturer

Type XM4 tenders were built in 1911 by the American Locomotive Company (ALCO).

In November 1911, the Central South African Railways (CSAR) placed a second batch of five {{nowrap|2-6-6-2}} Mallet articulated compound steam locomotives in service, built by ALCO. These locomotives were designated Class MF on the South African Railways (SAR) in 1912. The Type XM4 tender entered service as tenders to these five engines.

Characteristics

File:Diamond Frame bogie (coil).JPG

As built, the tender had a coal capacity of {{convert|10|lt|t|1|abbr=off}} and a water capacity of {{convert|4000|impgal|L|sigfig=3|abbr=off}}, with an average maximum axle load of {{convert|12|lt|15|lcwt|kg|sigfig=4|abbr=off}}. It rode on diamond frame bogies with a {{convert|5|ft|10|in|mm|0|abbr=off}} wheelbase per bogie.

Locomotive

In the SAR years, tenders were numbered for the engines they were delivered with. In most cases, an oval number plate, bearing the engine number and often also the tender type, would be attached to the rear end of the tender.Classification of S.A.R. Engines with Renumbering Lists, issued by the Chief Mechanical Engineer's Office, Pretoria, January 1912 (Reprinted in April 1987 by SATS Museum, R.3125-6/9/11-1000)

Only the second batch of five Class MF locomotives were delivered new with Type XM4 tenders. They were numbered in the range from 1629 to 1633, directly onto the SAR roster, marking the introduction of the SAR renumbering scheme under the Union programme.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, May 1945. p. 347.

Classification letters

Since many tender types are interchangeable between different locomotive classes and types, a tender classification system was adopted by the SAR. The first letter of the tender type indicates the classes of engines to which it can be coupled. The "X_" tenders could be used with the locomotive classes as shown.

The second letter indicates the tender's water capacity. The "_M" tenders had a capacity of {{convert|4000|impgal|sigfig=3|abbr=off}}.

A number, when added after the letter code, usually indicates differences between similar tender types, such as function, wheelbase or coal bunker capacity.

References

XM4