British Rail Class 52

The British Rail Class 52 is a class of 74 Type 4 diesel-hydraulic locomotives built for the Western Region of British Railways between 1961 and 1964. All were given two-word names, the first word being "Western" and thus the type became known as Westerns. They were also known as Wizzos and Thousands. The final Class 52 locomotives were withdrawn from service in 1977.

Historical context

When switching to diesel traction as part of the Modernisation Plan of the 1950s, British Railways designed, and commissioned designs for, a large number of locomotive types. At this time BR's regions had a high degree of autonomy, which extended as far as classes of locomotives ordered and even the design criteria for those locomotives. Whilst almost all other diesel locomotives were diesel-electric, the Western Region employed a policy of using diesel-hydraulic traction, originally commissioning three classes of main line locomotives: a type 2 and two type 4s. With pressure to increase the speed of the transition from steam to diesel, volume orders for the Class 22 and Class 42 followed in 1957, a mere two years after the original orders and well before any idea of performance or reliability could be gained.
At the same time it was realised that all the existing orders were for types 1, 2 and 4; thus orders were placed for 101 Type 3 diesel-hydraulics. However the increasing demands for more powerful locomotives prompted a further order, in 1961, for 74 diesel-hydraulics of ; so when the first locomotive was outshopped from Swindon Works in December 1961, less than a year after the order was placed, the Westerns were born.
The theoretical advantage of diesel-hydraulic was simple: it resulted in a lighter locomotive than equivalent diesel-electric transmission. This provided a better power/weight ratio and decreased track wear. Unfortunately, it had several key disadvantages.
The technology was proven in continental Europe, particularly Germany, but was new to the UK. At the time, it was considered politically unacceptable for the UK government to order railway rolling stock from foreign companies, especially German companies so soon after the Second World War. This resulted in most of the engines and transmissions being manufactured in the United Kingdom under licence from the German manufacturers.
Experience showed that the Bristol-Siddeley-Maybach engines were superior to those made by North British Locomotive Company-MAN and although the use of twin engines in the same locomotive was new, the design did not produce any insurmountable problems. In the end the diesel-hydraulic experiment foundered on low fleet numbers, poor maintenance conditions and design issues; not on its German heritage or development of a novel configuration. BR's Swindon Works maintained all the diesel-hydraulic locomotives, and their early demise resulted in a much reduced workload and hastened its eventual closure in 1986.

The Western

With the Hymeks and Warships already in service but proving underpowered for top-link services, BR Western Region needed a high-powered locomotive for these trains – the Western therefore needed two diesel engines to achieve the required power output. In keeping with their policy, a new locomotive with a hydraulic transmission was envisaged. Experience had shown that the Maybach engines in the Hymeks were superior to the earlier Maybach and MAN engines used in the Warships, particularly in power output. Also Maybach were able to offer their MD655 engines rated at allied to a Voith L630rV transmission; a Mekydro transmission designed to handle such power could not be fitted into the British loading gauge.
Prototypes sited the engines behind the driving cabs but drivers found this too noisy; moving the engines centrally meant making the locomotive heavier, removing some of the design's advantage. In operational use, the dual-engine arrangement turned out to have some advantages: in particular, the Westerns were able to continue operating with a single engine running in situations where more conventional single-engine designs would require rescue by another locomotive.
The most serious continual problem with the class was a mismatch between the Maybach MD655 engines and the Voith L630rV three speed hydraulic transmissions, a design fault. The top gear ratio in the transmission was too high for the torque characteristics of the engine: the result was that a single locomotive could struggle to reach its claimed top speed in the absence of down grades, more so when work-weary and due for overhaul. This factor, the South Devon Banks and the deleterious effect on worn-out engines, all contributed against the Westerns continuing in top-line service. With fifty locomotives becoming available following completion of the West Coast Main Line electrification, and new High Speed Trains, the speed and comfort increases the Western Region sought could be achieved and the Westerns dispensed with. Towards the end of their careers, the Westerns were all allocated to Laira.

Competition and comfort

Whilst the design was largely successful, the working life of the class was relatively short. Its non-standard design added to its maintenance costs at a time when national British Rail policy was moving away from diesel-hydraulics. When the Westerns were introduced in 1962, the Western Region had 226 diesel-hydraulics and 10 diesel-electrics ; by 1966, the numbers were 345 and 269 respectively. As a result, the early 1970s saw the decision taken to retire all the diesel-hydraulic types. and took over passengers and heavy freight, and took over light passengers and freight, and covered the lighter duties. Following completion of the electrification of the West Coast Main Line throughout from London Euston to, the were reallocated to the Western Region; the introduction of High Speed Trains three years later was the final nail in the coffin for the Class 52 Westerns.
In 1968–69, the Westerns received train air brake equipment in addition to their vacuum exhausters, thus significantly extending their working lives, unlike the similar but lower-powered, Warship class. Four of the class did not receive dual brakes, with these locomotives being among the first withdrawals. The vacuum brake equipment was retained and to fit the additional equipment, it was necessary to remove one of the fuel tanks. However, as with the Warships, it proved impossible to equip them with electric train heating. The Western Region faced particularly stiff competition for its prime inter-city services in the mid to late 1970s from the M4 motorway and it was generally felt within BR that significant speed and comfort improvements on the prime - route were necessary. The lack of ETH meant the Westerns could not power the newly introduced air-conditioned BR Mark 2d/e/f coaches – a shortcoming that classes 47 and 50, equipped with ETH, did not share.

Performance

The Westerns' highest recorded speed that O. S. Nock was aware of was when D1068 hauled nine coaches down 1 in 1,320 at. The train averaged exactly for between and whilst hauling a service from to Paddington.
However, in terms of drawbar horsepower the Westerns were in some ways less capable than similarly-powerful diesel electrics. Nock states "whilst the Westerns took their rightful place as fast and powerful locomotives it became evident that they were showing the same deficiency in actual power put forth at the drawbar as the Warships had done. The highest output that came to my notice was a sustained hauling 560 tons descending 1 in 1,320, which equates to 1,500 edhp ". A similar result was obtained when Clough & Beckett compared the performance of type 4 diesel locomotives hauling trains up the ascent to Whiteball summit. They deliberately chose data to show each class in their best light and included a Western run which produced 1,775 edhp but they still concluded that "without doubt the Westerns get the wooden spoon; certainly not what one would expect from units of 2,700 bhp". The best performer was the Class 50, a diesel-electric locomotive: on one run this achieved 2,115 edhp.
Despite this apparent limitation, the BR Western Region load-limit book gave the same 550 ton loading figure for both the Class 52 and Class 47 diesels over the South Devon banks between and. The reason for this is that, while the diesel-electric classes could produce high maximum tractive effort for limited periods, diesel hydraulics could produce significantly higher continuous tractive effort.

Fleet list

74 locomotives were built, entering service between December 1961 and April 1964. They were all withdrawn between May 1973 and February 1977. 67 were scrapped at Swindon Works, and 7 have been preserved including [|D1015] which is certified for running on the national rail network, and [|D1023] which was taken into the National Collection.
While the first Western was under construction, proposals for liveries and names were prepared by the BR design panel. It was suggested that the locomotives were to be named after West of England place names and D1000 was photographed with a mocked up Cheddar Gorge nameplate while it was being built. When it entered service it carried the name Western Enterprise and the other locomotives were all given names prefixed with 'Western' as listed below.
The 'Westerns' were designated Class 52 under the TOPS classification scheme. With the final withdrawal of steam traction in August 1968, the 'D' prefix became redundant and some locomotives did run with the 'D' painted over. In 1973 locomotives of other classes started to be renumbered with their class number followed by a three-digit locomotive number, but it was decided not to renumber the Class 52s as they were scheduled for early withdrawal.
Westerns were equipped with a four-position headcode display. British Rail stopped using these in the 1970s and the headcode was often set to display the locomotive's number. D1023 worked a special train from to in November 1976 and the headcode was replaced by marker lights at the request of the Eastern Region.

Number	Name			Withdrawn	Liveries	Status	Image
D1000	Western Enterprise	Swindon	20 December 1961	11 February 1974		Scrapped
D1001	Western Pathfinder	Swindon	12 February 1962	4 October 1976		Scrapped
D1002	Western Explorer	Swindon	19 March 1962	29 January 1974		Scrapped
D1003	Western Pioneer	Swindon	14 April 1962	5 January 1975		Scrapped
D1004	Western Crusader	Swindon	12 May 1962	1 August 1973		Scrapped
D1005	Western Venturer	Swindon	18 June 1962	14 November 1976		Scrapped
D1006	Western Stalwart	Swindon	6 July 1962	6 April 1975		Scrapped
D1007	Western Talisman	Swindon	1 August 1962	29 January 1974		Scrapped
D1008	Western Harrier	Swindon	4 September 1962	21 October 1974		Scrapped
D1009	Western Invader	Swindon		10 November 1976		Scrapped
D1010	Western Campaigner	Swindon	15 October 1962	27 February 1977		Preserved
D1011	Western Thunderer	Swindon	27 October 1962	6 October 1975		Scrapped
D1012	Western Firebrand	Swindon	17 November 1962	4 November 1975		Scrapped
D1013	Western Ranger	Swindon	13 December 1962	27 February 1977		Preserved
D1014	Western Leviathan	Swindon	24 December 1962	6 August 1974		Scrapped
D1015	Western Champion	Swindon	21 January 1963	13 December 1976		Preserved
D1016	Western Gladiator	Swindon	16 February 1963	28 December 1975		Scrapped
D1017	Western Warrior	Swindon	15 March 1963	1 August 1973		Scrapped
D1018	Western Buccaneer	Swindon	2 April 1963	11 June 1973		Scrapped
D1019	Western Challenger	Swindon	2 May 1963	6 May 1973		Scrapped
D1020	Western Hero	Swindon	21 May 1963	4 June 1973		Scrapped
D1021	Western Cavalier	Swindon	17 June 1963	10 August 1976		Scrapped
D1022	Western Sentinel	Swindon	16 July 1963	26 January 1977		Scrapped
D1023	Western Fusilier	Swindon	23 September 1963	27 February 1977		Preserved
D1024	Western Huntsman	Swindon	1 October 1963	18 November 1973		Scrapped
D1025	Western Guardsman	Swindon	1 November 1963	6 October 1975		Scrapped
D1026	Western Centurion	Swindon	24 December 1963	6 October 1975		Scrapped
D1027	Western Lancer	Swindon	28 January 1964	2 November 1975		Scrapped
D1028	Western Hussar	Swindon	25 February 1964	5 October 1976		Scrapped
D1029	Western Legionnaire	Swindon	20 April 1964	18 November 1974		Scrapped
D1030	Western Musketeer	Crewe	5 December 1963	19 April 1976		Scrapped
D1031	Western Rifleman	Crewe	20 December 1963	1 February 1975		Scrapped
D1032	Western Marksman	Crewe	31 December 1963	6 May 1973		Scrapped
D1033	Western Trooper	Crewe	17 January 1964			Scrapped
D1034	Western Dragoon	Crewe	15 April 1964	8 October 1975		Scrapped
D1035	Western Yeoman	Crewe	27 July 1962	5 January 1975		Scrapped
D1036	Western Emperor	Crewe	29 August 1962	29 October 1976		Scrapped
D1037	Western Empress	Crewe	31 August 1962	24 May 1976		Scrapped
D1038	Western Sovereign	Crewe	7 September 1962	8 October 1973		Scrapped
D1039	Western King	Crewe	7 September 1962	21 July 1973		Scrapped
D1040	Western Queen	Crewe	20 September 1962	27 February 1976		Scrapped
D1041	Western Prince	Crewe	10 October 1962	22 February 1977		Preserved
D1042	Western Princess	Crewe	19 October 1962	21 July 1973		Scrapped
D1043	Western Duke	Crewe	26 October 1962	5 April 1976		Scrapped
D1044	Western Duchess	Crewe	12 November 1962	1 February 1975		Scrapped
D1045	Western Viscount	Crewe	16 November 1962	16 December 1974		Scrapped
D1046	Western Marquis	Crewe	24 December 1962	11 December 1975		Scrapped
D1047	Western Lord	Crewe	4 February 1963	29 February 1976		Scrapped
D1048	Western Lady	Crewe	15 December 1962	27 February 1977		Preserved
D1049	Western Monarch	Crewe	14 December 1962	26 April 1976		Scrapped
D1050	Western Ruler	Crewe	1 January 1963	6 April 1975		Scrapped
D1051	Western Ambassador	Crewe	2 January 1963	2 September 1976		Scrapped
D1052	Western Viceroy	Crewe	4 February 1963	6 October 1975		Scrapped
D1053	Western Patriarch	Crewe	11 February 1963	13 November 1976		Scrapped
D1054	Western Governor	Crewe	2 March 1963	25 November 1976		Scrapped
D1055	Western Advocate	Crewe	2 March 1963	5 January 1976		Scrapped
D1056	Western Sultan	Crewe	8 March 1963	15 December 1976		Scrapped
D1057	Western Chieftain	Crewe	6 April 1963	30 April 1976		Scrapped
D1058	Western Nobleman	Crewe	25 March 1963	21 January 1977		Scrapped
D1059	Western Empire	Crewe	6 April 1963	6 October 1975		Scrapped
D1060	Western Dominion	Crewe	11 April 1963	18 November 1973		Scrapped
D1061	Western Envoy	Crewe	19 April 1963	21 October 1974		Scrapped
D1062	Western Courier	Crewe	6 May 1963	23 August 1974		Preserved
D1063	Western Monitor	Crewe	17 May 1963	5 April 1976		Scrapped
D1064	Western Regent	Crewe	24 May 1963	11 December 1975		Scrapped
D1065	Western Consort	Crewe	18 June 1963	30 October 1976		Scrapped
D1066	Western Prefect	Crewe	14 June 1963	12 November 1974		Scrapped
D1067	Western Druid	Crewe	18 July 1963	2 January 1976		Scrapped
D1068	Western Reliance	Crewe	12 July 1963	13 October 1976		Scrapped
D1069	Western Vanguard	Crewe	21 October 1963	6 October 1975		Scrapped
D1070	Western Gauntlet	Crewe	28 October 1963	30 December 1976		Scrapped
D1071	Western Renown	Crewe	7 November 1963	7 December 1976		Scrapped
D1072	Western Glory	Crewe	7 November 1963	2 November 1976		Scrapped
D1073	Western Bulwark	Crewe	3 December 1963	29 August 1974		Scrapped