LSWR S15 class

Infobox Locomotive
powertype=Steam
name = LSWR/SR S15 classHerring, Peter, "Classic British Steam Locomotives" (Abbeydale Press: London, 2000) Section "S15 Class" Pages 100 to 101 ISBN 1861470576]


caption = Preserved No. 825 at Pickering, October 2005
designer = Robert Urie, modified by Richard Maunsell
builder = LSWR/SR Eastleigh Works
builddate = 1920–1936
totalproduction = 45
whytetype = 4-6-0
uicclass = 2'Ch
gauge = RailGauge|ussg|lk=on
leadingsize = convert|3|ft|7|in|m|3|abbr=on
driversize = convert|5|ft|7|in|m|3|abbr=on
length = convert|65|ft|6.75|in|m|2|abbr=on
weight = Urie: 135 tons 21 cwt (138.1 tonnes) Maunsell: 135 tons 13 cwt (137.7 tonnes)
fueltype = Coal
fuelc

waterc
convert|5000|impgal|l|abbr=on|lk=on
cylindercount = Two
cylindersize = 20½ × 28 in (533 × 711 mm)
valvegear = Walschaerts
boilerpressure = Urie locomotives: convert|185|psi|MPa|2|abbr=on|lk=on; Saturated Boiler: convert|175|psi|MPa|2|abbr=on; Maunsell locomotives: convert|200|psi|MPa|2|abbr=on
tractiveeffort = convert|29857|lbf|kN|2|abbr=on|lk=on
retiredate = 1962–1966
disposition = Seven preserved, remainder scrapped

The LSWR S15 class is a class of 4-6-0 steam locomotive designed for freight work. They were designed by Robert Urie for the London and South Western Railway (LSWR). After design modifications several more were built by Richard Maunsell for the Southern Railway.

A total of 45 were constructed at Eastleigh Works between 1920 and 1936, and saw service all over the Southern Railway's Western and Central sections. All class members saw service with the Southern Region of British Railways, although all had been withdrawn by 1966. Seven examples of the class have survived into preservation.

Background

The LSWR wished to address the requirement for a modern, standardised heavy freight locomotive to work from London's Feltham freight yard to the southwest of England. For this role a new design was needed to serve the south coast ports of Portsmouth, Weymouth and Southampton; it was also to power other forms of traffic, such as milk trains, which required fast transit to the dairies in London.Russell, J. H.: "A Pictorial Record of Southern Locomotives" (Oxford Publishing Company: Oxford), (no ISBN given)] Robert Urie saw the design potential of his LSWR Class H15, and saw this as an opportunity to further develop the 4-6-0 locomotive concept into a purpose-built freight design that was to become the Class S15.

Construction history

The first (Urie) batch

The S15 was the third design by Robert Urie for the LSWR. Initiated during the First World War, the design incorporated the lessons learned from the operation of his H15 class, a design that was to provide the basis for future standardisation on the LSWR.Bradley, D. L.: "LSWR Locomotives - the Urie classes" (Wild Swan Publications, 1987), ISBN 090686755X ] Due to the constraints of wartime, the class was designed to have interchangeable components with a similar design, the N15 class. Details such as the boiler, the two-cylinders and valve gear were standardised between both classes, although the principal difference lay in the diameter of the driving wheels. The S15, being primarily a fast freight locomotive, had smaller diameter wheels to give better traction.

The first batch was constructed at Nine Elms, with the first of these new freight locomotives entering traffic in February 1920. By May 1921 sixteen were in service, mostly allocated to the London area.

Urie retired after the creation of the Southern Railway in 1923. Richard Maunsell, the new Chief Mechanical Engineer, took the decision to revise the cylinder arrangements of the locomotive, and in so doing delayed the construction of further locomotives until the modifications had been made. Maunsell took a sound design and made it better, achieving a consistent locomotive that could undertake all tasks it was produced for.

The second and third (Maunsell) batches

Maunsell's modifications entailed the increase of boiler pressure from 180lbf/in² to 200lbf/in² and the reduction of cylinder diameter by half an inch.Haresnape, Brian: "Maunsell Locomotives - a pictorial history" (Ian Allan Ltd, 1977), ISBN 0711007438] Additionally the footplate was modified, valve travel was lengthened, and larger outside steam pipes were fitted to improve flow into the cylinders. Fifteen of the revised design were built at Eastleigh in 1927, and some were allocated six-wheeled tenders for use on the Southern's Central section. This allowed the locomotive to be turned on the shorter turntables located on this part of the network. From new, the rest of the class was equipped with the Urie convert|5000|impgal|l|abbr=on|lk=on eight-wheel bogied tender, which enabled the class to operate on the extended freight routes of the Southern Railway's Western section. The standardisation of the design was soon evidenced by the fact that tenders were swapped between other classes on the Southern.

The benefits gained by the modifications showed in the visibly improved performance of the first batch of Maunsell S15s over their Urie-built predecessors. A further batch was ordered in 1931, though this coincided with a downturn in the volume of freight due to the economic depression, therefore dictating that the last S15 4-6-0s were not completed until 1936. Around this time the entire class was equipped with smoke deflectors, a modification that was made to all Maunsell-influenced designs.

Livery and numbering

LSWR and Southern Railway

Under LSWR ownership the S15s were outshopped in the late LSWR dark Holly Green livery, with black and light green lining, which was applied to most freight designs of the LSWR. Gilt lettering and numbering was located on the tender and cabside respectively. Swift, Peter: "Maunsell 4-6-0 King Arthur Class" (Locomotives in Detail series volume 4) (Hinckley: Ian Allan Publishing, 2006), ISBN 0711030863 ] The initials "LSWR" were located on the tender.

The first Southern Railway livery continued that of the LSWR, though with the number displayed on the tender. However, from 1925, a darker Olive-type green was substituted, and the entire class was so outshopped.Wheels were green with black tyres, and the cabside numbers were replaced by a cast oval plate with "Southern Railway" around the edge and the number in the centre. Primrose Yellow "Southern" and locomotive number transfers were placed on the tender tank. From 1927 the Maunsell locomotives were outshopped in black livery with green lining, and were to remain in this guise with little modification until nationalisation.

The only slight livery modification occurred before the Second World War, when Oliver Bulleid introduced the "Sunshine Yellow" lettering and numbering. A further modification was the application of a green shaded "Sunshine" lettering during the war. This was finally reverted to "Sunshine Yellow" lettering and numbering after the war. No.823–837 were delivered from Eastleigh during 1927 and 1928 and a further ten, No.838–847 were authorised in 1931.

Post-1948 (nationalisation)

After a period in British Railways transitional livery the entire class was released in British Railways Freight Black livery with no lining, numbering located on the cabsides and the BR crest on the tender sides. Longworth, Hugh: "British Railway Steam Locomotives: 1948–1968" (Oxford Publishing Company: Oxford, 2005) ISBN 0860935930] Numbering was initially as per Southern Railway with an "s" prefix, though eventually allocated the British Railways Standard System in the series of 30823–30837 for the second batch, and 30838–30847 for the third.

Operational details

The Maunsell-modified design provided an excellent goods engine and it was best known for working heavy night express goods trains between Exeter and Nine Elms, Southampton. They were also vary capable passenger engines when used during peak holiday periods. Both the Urie and Maunsell S15s spent most of their working lives on the Southern's Western section. Eventually all the Urie engines were concentrated at the Southern's London freight depot in Feltham. As well as Feltham, the Maunsell S15s were allocated to Exmouth Junction, Hither Green and Salisbury, indicating the "go anywhere" nature of the class. The S15s outlived the King Arthur class because of their dual freight/passenger abilities. However, they were retired between 1962 and 1966 as part of the British Railways Modernisation Plan. Maunsell S15 number 30837 was the final operational example of the class, returning to Feltham in January 1966 to work a farewell rail tour.

Preservation

Seven S15s have been preserved, with two built by the LSWR and five by the Southern Railway:

* 30499 East Lancashire Railway – still in scrapyard condition
* 30506 Watercress Line
* 30825 North Yorkshire Moors Railway
* 30828 Watercress Line
* 30830 North Yorkshire Moors Railway
* 30841 North Yorkshire Moors Railway
* 30847 Bluebell Railway

References

Further reading

*Allan, Ian: "ABC British Railways Locomotives Part 2 - Nos. 10000-39999" (Ian Allan Ltd: 1949)

External links

* [http://www.semgonline.com/steam/s15class_1.html SEMG gallery]
* [http://www.railuk.co.uk/steam/getsteamclass.php?item=S15 Railuk database]
* http://www.bluebell-railway.co.uk/bluebell/loco_overhaul.html#847