LSWR D15 class

The LSWR D15 class 4-4-0 was the last steam locomotive design by Dugald Drummond for the London and South Western Railway in 1912.

Infobox Locomotive
powertype=Steam
name = LSWR/SR D15 class Bradley, D. L. (1986)]


caption =
designer = Dugald Drummond
builder = LSWR Eastleigh Works
builddate = 1912–13
totalproduction = 10
whytetype = 4-4-0
uicclass = 2'Bh
gauge = RailGauge|ussg|lk=on
leadingsize = convert|3|ft|7|in|m|3|abbr=on
driversize = convert|6|ft|7|in|m|3|abbr=on
length = convert|63|ft|9|in|m|2|abbr=on
weight = 59 tons, 15cwt (60.7 tonnes) (orig); 61tons 11cwt (62,5 tonnes) (superheated version)
tenderweight = 49 tons 0 cwt (49.8 tonnes) (8-wheel)
36 tons 14 cwt (37.3 tonnes) (6-wheel)
superheatertype = Drummond smokebox type, "later" Eastleigh, "later" Maunsell
fueltype = Coal
fuelc

waterc
convert|4500|impgal|l|abbr=on|lk=on (8-wheel tender)
convert|3500|impgal|l|abbr=on (6-wheel tender)
cylindercount = Two, inside
cylindersize = 19½ × 26 in (495 mm × 660 mm)
valvegear = Walschaerts
boilerpressure = convert|200|psi|MPa|2|abbr=on|lk=on (original version); convert|180|psi|MPa|2|abbr=on (smoketube superheater versions.)
tractiveeffort = convert|22333|lbf|kN|2|abbr=on|lk=on (as built); convert|20100|lbf|kN|2|abbr=on (superheated)
railroad=London and South Western Railway, Southern Railway (Great Britain), Southern Region of British Railways
locale=Great Britain
railroad=London and South Western Railway
Southern Railway
British Railways
railroadclass=LSWR, SR & BR: D15
BR power group: 3P
retiredate=1951–1956
roadnumber=SR & LSWR: 463–472
BR: 30463–30472
disposition=All scrapped

Background

By 1912, Dugald Drummond had built several classes of unsuccessful 4-6-0 express passenger locomotives. The result of these failures was that when he designed what was to be his last class in 1911, a new 4-4-0 design emerged from Eastleigh workshops in February 1912, with what was to be the first of his D15 class.

Construction history

In line with the typical Drummond layout, the D15s had a short smokebox with wing plates. The boiler was based on that fitted to the 1905 rebuild of his first double-single, T7 class number 720 of 1897; and had a long firebox with a sloping grate. This resulted in the boiler being pitched higher than usual in order to allow clearance over the trailing axle. An exhaust steam feed water heater was provided and the boiler fed by duplex pumps located on the frames, between the coupled wheels. The class was initially given the "intermediate" type of eight-wheel, double bogie tender with inside bogie frames carrying 4 tons (4.06 tonnes) of coal and 4,500 gallons (20.5m³), due to the lack of water troughs on the line.

After Drummond's death, Robert Urie, his successor, fitted the class with Eastleigh superheaters. These had a very small superheating surface, they were replaced by Maunsell superheaters, when Richard Maunsell was appointed Chief Mechanical Engineer of the Southern Railway after the grouping of 1923. By this time, the eight-wheeled tenders had been replaced by six wheeled 3,500 gallon (15.9m³) versions transferred from K10 and L11 locomotives.

Operational details

Contrary to Drummond's previous 4-6-0 designs, the D15s performed exceptionally well and were put to work on trains to Bournemouth, where many drivers noted their superior operational characteristics when compared to the T14 class 4-6-0s. This was due to a marked reduction in coal, water and oil consumption, and easier maintenance. However, with the succession of Urie, no further D15s were constructed, as he preferred to concentrate on 4-6-0 designs. These successful locomotives worked, in the main, out of Waterloo and prior to electrification had a virtual monopoly of the Portsmouth expresses. Until the advent of the Bulleid Light Pacifics, a D15 was usually to be found working the Brighton to Plymouth service. Number 468 differed from the rest of the class in that it had the safety valves mounted on the firebox, with Urie N15 style dome and safety valve casings, whilst the others had Drummond direct-loaded safety valves on their domes. As built, number 463 was fitted with a hooter rather than a whistle, which it kept until the Second World War. The class continued into British Railways service, though were gradually withdrawn in the early 1950s. This meant that none survived to be preserved.

Livery and numbering

LSWR and Southern

Under the LSWR, the D15s were outshopped in the LSWR Passenger Sage Green livery with purple-brown edging, creating panels of green. This was further lined in white and black with 'LSWR' in gilt on the tender tank sides. They were numbered 463–472 in a continuous block.

When transferred to Southern Railway ownership after 1923, the locomotives carried Richard Maunsell's darker version of the LSWR livery. Swift, Peter (2006)] The LSWR standard gilt lettering was changed to yellow with 'Southern' on the water tank sides. The locomotives also featured black and white lining.Haresnape, Brian; Peter Rowledge (1982), p. 91]

Post-1948 (nationalisation)

Livery after Nationalisation was initially Southern freight livery with 'British Railways' on the tender, and an 'S' prefix on the number. The class was subsequently outshopped in BR Mixed Traffic Black with red and white lining, with the BR crest on the tender.Longworth, Hugh (2005)] Locomotive numbering was per BR standard practice, with several locomotives passing into British Railways ownership in 1948.

References

Notes

Bibliography

*cite book |author=Bradley, D. L. |year=1986 |title=An illustrated history of LSWR Locomotives: the Drummond Classes |location = Didcot, Oxon |publisher = Wild Swan Publications |isbn=0906867428
*cite book |author=Haresnape, Brian |coauthors=Peter Rowledge |year=1982 |title=Drummon Locomotives, a pictorial history |location = Shepperton, Surrey |publisher = Ian Allen Limited |pages=pp.91–93 |isbn=0 7110 1206 7
*cite book |author=Longworth, Hugh |year=2005 | title=British Railway Steam Locomotives: 1948–1968 |publisher = Oxford Publishing Company |isbn=0 86093593 0
*cite book |author=Swift, Peter |year=2006 | title=Locomotives in detail volume 4: Maunsell 4-6-0 King Arthur Class |location = Hinkley |publisher = Ian Allen Publishing |isbn=0 7110 3086 3

External links