LMS Princess Coronation Class

Infobox Locomotive
powertype=Steam
name = LMS Princess Coronation Class

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caption = Preserved 6233 "Duchess of Sutherland" running in 2001. She is roughly in the same condition as between 1941 (when a double chimney was fitted) and 1945 (when she received her smoke deflectors).
designer = William Stanier
builder = LMS Crewe Works
builddate = 1937–1948
totalproduction = 38
whytetype = 4-6-2
uicclass=2'C1'h
gauge = RailGauge|ussg
leadingsize = convert|36|in|m|3|abbr=on
driversize = convert|81|in|m|3|abbr=on
trailingsize = convert|45|in|m|3|abbr=on
length = 73 ft 10¼ in (conventional),
73 ft 9¾ in (streamlined)
weight = 105t 5cwt (conventional),
108t 2cwt (streamlined),
108t 10cwt (6256/57) .
fueltype = Coal
fuelc
convert|10|LT|t|1
waterc
convert|4000|impgal|l|abbr=on|lk=on
cylindercount = 4
cylindersize = 16½×28 in (419×711 mm)
valvegear = Walschaerts for outside cylinders with rocking shafts for inside cylinders, piston valves
boiler= LMS type 1X
firearea = convert|50|sqft|abbr=on
fireboxarea = convert|230|sqft|abbr=on
tubearea=convert|2577|sqft|abbr=on
superheaterarea=822–856 sq ft (76.4–79.5 m²)
boilerpressure = convert|250|psi|MPa|abbr=on|lk=on superheated
tractiveeffort = convert|40000|lbf|kN|abbr=on
railroadclass= 7P, later 8P
retiredate = 1962–1964
disposition= Three preserved, remainder scrapped

The Princess Coronation Class is a class of express passenger steam locomotives built by the London Midland and Scottish Railway (LMS) and designed by William Stanier. They were an enlarged version of the LMS Princess Royal Class. Several examples were originally built as streamlined, though this was later removed. The non-streamlined locomotives were often referred to as the "Duchess Class". To enginemen they were all known as "Big Lizzies". It is widely held that they were the most powerful passenger locomotives ever to serve on the British railway network.

Overview

The first five, 6220-4, were built in 1937. They were streamlined and painted Caledonian Railway blue with silver horizontal lines to match the "Coronation Scot" train they were built to haul. The streamlining is probably best described as like an upside down bathtub and was largely for publicity reasons- Stanier, the designer of the Locomotives felt that the added weight and difficulty in maintenance due to the streamlining was too high a price to pay for the actual benefits at high speed. The second five, 6225-9, were also streamlined, but painted in the more traditional crimson lake, with gilt horizontal lining. This was to match standard LMS stock and a planned brand new Coronation train made up of articulated coaches. Although a prototype for this was built and exhibited in America it was never put into service due to World War II.

The next batch was built un-streamlined. They were considered to be very handsome locomotives. Smoke deflectors were added from 1945 due to drifting smoke obscuring the crew’s forward vision.War interrupted the building of the locomotives, but given the dire shortage of express motive power several more were then finished during the war and turned out in unlined black. 6253-57 were turned out in the 1946 LMS lined black and 46257 was turned out in BR black. Two locomotives to a modified design by George Ivatt were built in 1947 (6256) and 1948 (46257).

Single chimneys were fitted to 6220-6234 when built but they were replaced with double chimneys between 1939 and 1944. 6235 onwards were built with double chimneys. Smoke deflectors were fitted from 1945 with the last 5 carrying them from new.

An unusual feature of the tenders was that they were fitted with a steam-operated coal pusher to bring the coal down to the firing plate. When this was in operation a plume of steam could be seen rising from the rear face of the coal bunker backwall.

De-Streamlined Locomotives

The streamlining was removed from the fitted locomotives from 1946 onwards. It had been found to be a little value at speeds below convert|90|mi/h|km/h|abbr=on, and was unpopular with running shed staff. Only 3 were still fitted at the end of the LMS period and they had been stripped by the end of 1949. Only 46243 "City of Lancaster" carried its British Railways number whilst streamlined.

Initially de-streamlined locomotives could readily be recognised by the sloping top to the smokebox. All were eventually replaced with fully round smokeboxes. The sloping top led to the train-spotters nickname of "Semis" (i.e. "semi"-streamlined).

Liveries

The livery history for these locomotives involves no fewer than 11 variations. :LMS Streamliner – Blue, Red, Wartime Black:LMS Non-streamliner – Red, Wartime Black, 1946 Black:BR Experimental – Blue, Black:BR Standard – Blue, Green, Red

BR Blue was carried by 25 of the 38 locomotives; the first two being so painted in May 1949, one locomotive is known to have carried the blue livery until June 1954. All locomotives carried Green. Only 16 locomotives were painted BR Red and these were allocated to the London Midland Region; Scottish Region allocated locomotives remained Green.

Technical

* Power Classification: 7P, reclassified 8P in 1951.
* Introduced: 1937-1948
* Designer: William Stanier
* Weights:
**Loco: - 105 t 5 cwt (Conventional), 108 t 2 cwt (Streamlined), 108 t 10 cwt (Ivatt) .
**Tender: 56t 7cwt
* Driving Wheel: convert|6|ft|9|in|m|abbr=on
* Boiler pressure: 250 psi superheated
* Cylinders (4): 16 ½ " x 28"
* Tractive Effort: convert|40000|lbf|kN|abbr=on
* Valve Gear: Outside Walschaerts with rocking shafts (piston valves)

Gallery

Details

Preservation

Three Duchesses have survived. (4)6229 "Duchess of Hamilton", (4)6233 "Duchess of Sutherland" have both seen action on main line railtours. "Duchess of Hamilton", now out of working order, is in the process of a "Steam Railway" appeal to have her restreamlined. The third, (4)6235 "City of Birmingham" was the centrepiece in the, now defunct, Birmingham science museum. (4)6235 was put in place and the museum built around her. (4)6235 is now located at ThinkTank in Birmingham.

Following a successful appeal run by Steam Railway Magazine, 46229 is to be re-streamlined. The locomotive has been moved to Tyseley Locomotive Works, where the work is being carried out. The project will be completed by June 2008, when the locomotive will return to York for the 70th anniversary of the Coronation Scot service - taking her place at the heart of a new National Railway Museum temporary exhibition.

Sound

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References

* David Jenkinson (1980) "The Power of the Duchesses" Oxford Publishing Company ISBN 0-86093-063-7
* Ian Sixsmith " The Book of the Coronation Pacifics" ISBN 1-871608-94-5
* Hugh Longworth "British Railway Steam Locomotives 1948-1968" ISBN 0-86093-593-0
*

External links

* [http://www.prclt.co.uk/ Princess Royal Locomotive Trust] (owners of 6233)
* [http://www.thinktank.ac/ Thinktank, Birmingham science museum] (6235 on display)
* [http://www.railuk.co.uk/steam/getsteamclass.php?item=CORO/ Princess Coronations]