British Rail Class 42

thumb|480x480px
The BR Class 42s are diesel-hydraulic locomotives that were built from 1958 - 1961. Class 41s and Class 43s (Not to be confused with the diesel-electric locomotive) are also Warship classes. They have the Bo-Bo configuration where they have four axles, and two individual bogies (or trucks).
== Mechanical details ==
The class was based on the DB Class V 200. Each locomotive was powered by two Maybach 1035 hp (D800–802) or 1135 hp (D803–829, D831–832 and D866–870) MD650 engines coupled to Mekydro hydraulic transmissions. Although these diesel engines were of German Maybach design, they were physically manufactured by Bristol Siddeley at their factory at Ansty, near Coventry, under licence. The lower engine rating in the first three was because the first batch of transmissions could not accept more than this; a shortcoming swiftly rectified, although the technology of the time limited hydraulic transmissions to below 2,000 hp (1,500 kW) input, hence the need for two engines. D830 Majestic was equipped with two Paxman YJXL Ventura engines rated at 1,200 hp (890 kW) each as a potential showcase of an alternative British-designed engine which might prove superior to the German Maybach. The new locomotives were substantially lighter than previous diesel-electric designs: a Class 44 Peak locomotive weighed 138 long tons (140 t; 155 short tons) and required 8 axles to carry it; the D800s weighed less than 80 tons and only needed 4 axles. D800–802 were produced as a pilot order and differed slightly both mechanically and cosmetically from the others. Aside from the obvious differences of disc versus rollerblind headcodes and the slightly less powerful engines, D800–802 were only equipped with six power controller notches, which was found to be unsatisfactory for smooth acceleration and economical running in operational use. These differences meant D800–802 were effectively a separate sub-class and could not work in multiple with the others (although the "white diamond" code multiple working capability of the Warships was rarely used until the late 1960s, and was removed from many locomotives as a constant source of electrical problems). In 1960 British Rail introduced the Class 43 diesel hydraulic locomotives, with a maximum tractive effort of 53,400 pounds-force (238,000 N). These were constructed by North British Locomotives, numbered in the range D833 to D865 and also bore names. Although of a very similar design to the Swindon-built examples, the 43s were equipped with MAN engines and Voith hydraulic transmissions at a similar power rating as the Swindon locomotives. The Maybach engines were a more sophisticated design, with advanced features such as oil-cooled pistons that the MAN design lacked. The German V200 class, upon which the D800 design was based, used Mercedes and Maybach engines – the MAN engines were not fitted in significant numbers to V200 locomotives – coupled to Mekydro and Voith transmissions in roughly equal proportions, with engines and transmissions being completely interchangeable. Thus one locomotive might have one Mercedes engine coupled to a Mekydro transmission and a Maybach coupled to a Voith. This interchangeability of engines and transmissions was theoretically a feature of the BR design as well, but was never exploited. Detail differences in the floor construction after the first few Swindon production locomotives removed the ability to exchange transmissions.
== Names and liveries ==
Each locomotive bore a name: for example D825 was Intrepid. All except D800 and D812 were named after Royal Navy vessels, thus the "Warship diesel" moniker used to refer to the class. D800 was named Sir Brian Robertson after the Chairman of the British Transport Commission at the time. D812 was planned to carry the name Despatch but was eventually named Royal Naval Reserve 1859–1959. All except these two bore a subtitle "Warship Class" in smaller letters underneath the main name. A nice touch was that throughout the production series examples (including the NBL-built D833–865) the names were allocated alphabetically. This caused some difficulty when Swindon was unexpectedly given an order for five more locomotives (which became D866–870); a shortage of Warship names beginning with Z required some names for the higher numbered NBL examples to be reallocated. The original livery for all D800s was BR green with a light grey waistband and red bufferbeams. In the mid-1960s the WR decided upon maroon as its new house colour for mainline diesel locomotives, this going very much against standard schemes imposed by BR's overall management. In November 1966 the first D800 (D864) appeared in the new BR blue scheme with D864 carrying an experimental 'Burnt Umber' paint scheme around the lower skirting (an attempt to mask out brake dust). Half yellow nose ends appeared from January 1962 and eventually two Green, several Maroon and all Blue-liveried locomotives received full yellow ends. Green livery was eradicated by 1970 when D810 was repainted, this being the last green member of the class in service, although D800 had still carried the green livery when withdrawn in 1968. A handful of Maroon examples, including D809, D815 & D817 remained in traffic until 5 October 1971, and were finally withdrawn in this colour scheme, although by now wearing full yellow ends. Three of the early withdrawals, D801, D840 and D848, met their end in maroon with small yellow panels. After withdrawal of steam in 1968, the "D" prefix was dropped from locomotive running numbers when repaints occurred – so for example, D832 became just 832 as there was now no chance of it conflicting with a steam locomotive number.
==History==
The D800s were originally intended for the Paddington–Birmingham Snow Hill route and tests proved that their extra weight and power allowed them to run to a two-hour schedule with 368 tons in tow: one coach more than a Class 40 could manage. These plans were put back when Paddington became the temporary London terminus of choice for Birmingham during the early 1960s, whilst BR's preferred route from Euston via Rugby was electrified. Loads of greater than 370 tons would be required and the service remained steam-hauled until the advent of the more powerful Class 52 Western diesel-hydraulic locomotives. The first service route for the class therefore became Paddington–Penzance, either via Swindon and Bristol, or via Newbury and Westbury on the "Berks and Hants" route. This allowed for elimination of steam on the difficult-to-operate railway west of Newton Abbot. In October 1958 D800 became the first locomotive to take up the class's new diagram of the up Cornish Riviera Express (Penzance to Paddington), the 18:30 Paddington–Bristol and the 21:05 Bristol–Plymouth – the last part of the diagram allowing the locomotive to return to the brand new depot at Laira in Plymouth once this was fully operational in 1961.
The maximum speed of the D800 class was officially 90 mph (140 km/h) but this could not be rigidly enforced because the transmissions could not be precisely governed. 102 mph (164 km/h) was recorded by D801 in private tests during 1959, albeit on a downgrade. The summer of 1959 saw 100 mph (160 km/h) service trains diagrammed for D800s with the Paddington–Bristol "Bristolian" set a schedule of 100 minutes. The outward journey was via Bath and required an average speed of 71 mph (114 km/h) and the return journey via Badminton averaged at 70.6 mph (113.6 km/h). For a very brief period the D800s achieved both the schedule and more with D804 exceeding 100 mph (160 km/h) three times on one early run from Bristol. This was soon ended when the Western Region's civil engineers imposed a blanket 90 mph (140 km/h) maximum speed on all the Region's main lines, where for five years there had, uniquely to BR at the time, been no restrictions at all. The root cause of this worry was the effect of small-diameter powered wheels carrying far more weight per inch of tread than those of a steam locomotive. These concerns arose particularly from experiences in the United States of America although the significant rail damage reported there was mostly caused by wheel sliding under braking with heavy trailing loads which were very unlikely to occur on BR. With the benefit of modern hindsight it is possible that, even though the full US experience would not be replicated, "gauge corner cracking" (the formation of microscopic cracks in the rails that was the primary cause of the Hatfield rail crash of 17 October 2000 in the UK) could have been a possibility if the schedules had been adhered to.
In the event, several D800 drivers began reporting uncomfortable lurching over points or on poorly maintained track at high speeds around this time. The problem was eventually traced to the novel design of the bogies and their means of attachment to the locomotive bodyshell: it had given the German V200s no trouble because of the 140 km/h (87 mph) V200s speed limit on the German Federal Railway at the time. High speed running magnified the effect of the almost rigid link between body and bogie, and oscillations created in the entire locomotive structure when the wheels hit pointwork or indifferent track made derailment a very real risk as the tyres on the wheels wore down. The D800s were subject to a maximum speed of 80 mph (130 km/h) until all class members could be modified – this was not achieved until 1963. The "Bristolian" was decelerated by 5 minutes but an extra stop at Chippenham was inserted so that the drivers practically had no choice but to exceed 80 mph (130 km/h) to keep to time. All speed running ceased after autumn 1960, when BR's timetabling methodology as a whole changed towards making all inter-city services more regular interval with standardised train formations and more intermediate stops. No longer would crack expresses such as the "Bristolian" be given such priority: the hope (largely successful) was to increase locomotive and coaching stock productivity and also increase passenger numbers in an attempt to curb BR's still-increasing monetary losses.
By 1964, the influx of both more powerful "Western" diesel-hydraulics and Class 47s drafted into the WR by BR's higher management, meant that some D800s were spared for use on the Waterloo–Exeter route. At this time, the Western Region (formed upon Nationalisation in 1948 largely from the Great Western Railway) had just assumed control of this line west of Salisbury from the Southern Region of British Railways and conveniently used the "no more crack expresses" edict to get revenge on its pre-Nationalisation rival the Southern Railway by withdrawing altogether the SR's Atlantic Coast Express, which worked beyond Exeter, and replacing it with a semi-fast Waterloo–Exeter service hauled by D800s. The WR also took the opportunity to reduce its former rival's main line to single track for long stretches west of Salisbury and to sell off the "surplus" land – a move that is widely regretted today.
The late 1960s saw a brief revival in the fortunes of the D800s. For a few months in late 1967 they moved on to the Paddington–Birmingham New Street route and then in early 1968 Paddington–Hereford. Rising traffic levels on the Paddington–Plymouth route meant the WR aspired to an hourly service interval for this route with standard 10 and 12 carriage trains. The maximum schedule was to be 4 hours 15 minutes for the 225.5 mi (362.9 km), but the "Cornish Riviera Express" would be retimed for 3 hours 45 minutes with stops at Taunton and Exeter only. The Class 52 Westerns could only cope with these timings on seven carriage trains. The answer was to assemble pairs of D800s and reinstate the multiple working equipment on them, to allow the pair to be controlled by one driver. This was done with D819/22–24/27–29/31/32 and D866–69 and the acceleration in schedules did bring a further 7% increase in traffic levels. It was not, however, without its problems: a fault on one locomotive in a multiple-unit pair effectively disabled both and one alone could not keep to the schedules. By 1969 only two services were booked for a pair of D800s, albeit losing a further 15 minutes off the schedule, and the timetable was largely recast into separate Torbay and Plymouth trains, instead of being split en route. This allowed the formations to revert to eight or nine carriages that a single Western could handle alone.
== Withdrawal ==
Prejudice against hydraulic transmission in the higher echelons of BR's engineering divisions decreed in 1967 that all the WR's diesel-hydraulics were non-standard and should be withdrawn as soon as possible. Added to this were practical problems modernising the D800s: because of the scaled-down bodyshell there was very little room inside for extra equipment. It was, for example, physically impossible to accommodate a compressor as well as an exhauster, so the locomotives were unable to haul newer designs of air-braked coaching stock. It also proved impractical to equip them with electric train heating (ETH) equipment, for similar reasons, so they retained unreliable steam heat boilers to the end of their lives. It was intended to equip no. D870 with ETH; to provide the necessary additional power, the engines would have been uprated by the fitment of charge-air coolers. No work was actually carried out, other than the fitment of appropriate jumper cables on the locomotive ends.
The pilot build trio were all withdrawn by early October 1968, these being followed by D830 and three of the NBL Class 43s (D840/48/63) in 1969, no withdrawals in 1970 and then mass withdrawals in 1971 which saw the NBLs extinct by October. Several of the Class 42s survived into 1972 and the last were withdrawn by the end of that year. Many withdrawn examples were hastily cannibalised for spare parts to keep the others going as stocks had been reduced in anticipation of a swifter end to D800 operation than was in the event possible. The "Cornish Riviera Express" remained booked for two D800s until the May timetable change in 1970. Because of their early withdrawal dates, TOPS numbers were never allocated, although the Swindon-built locomotives were allocated TOPS Class 42 and the NBL examples Class 43.
Year	Quantity inservice atstart of year	Quantitywithdrawn	Locomotive numbers 	Notes
1968	38 	3 	D800-2 	
1969	35 	1 	830 	
1970	34 	0 	– 	
1971	34 	15 	804/8-9/15/17/19/22-3/26/28/31/67-70 	870 went into departmental use.
1972	19 	19 	803/5-7/10-4/16/18/20-1/24-5/27/29/32/36	818 and 832 went into departmental use. 821 and 832 preserved.
== Class details ==
Running number	Name 	Date to traffic 	Date withdrawn 	Notes
D800 	Sir Brian Robertson 	11 August 1958 	5 October 1968 	Built at Swindon, lot no. 428. Date of order January 1956.
Cut up at J Cashmore Ltd, Newport
D801 	Vanguard 	7 November 1958 	3 August 1968 	Cut up at Swindon
D802 	Formidable 	16 December 1958 	5 October 1968 	Cut up at Swindon
D803 	Albion 	16 March 1959 	1 January 1972 	Built at Swindon, lot no. 437. Date of order February 1957.
Cut up 6 October 1972 at Swindon
D804 	Avenger 	23 April 1959 	3 October 1971 	Cut up 24 March 1972 at Swindon
D805 	Benbow 	13 May 1959 	24 October 1972 	Cut up 16 May 1973 at Swindon
D806 	Cambrian 	3 June 1959 	2 November 1972 	Cut up 1 May 1975 at Swindon
D807 	Caradoc 	24 June 1959 	26 September 1972	Cut up 3 November 1972 at Swindon
D808 	Centaur 	8 July 1959 	3 October 1971 	Cut up 25 February 1972 at Swindon
D809 	Champion 	19 August 1959 	3 October 1971 	Cut up 6 October 1972 at Swindon
D810 	Cockade 	16 September 1959	3 December 1972 	Cut up 26 September 1973 at Swindon
D811 	Daring 	14 October 1959 	1 January 1972 	Cut up 13 October 1972 at Swindon
D812 	The Royal Naval Reserve 1859–1959	12 November 1959 	3 November 1972 	Was to have been named Despatch
Cut up 4 July 1973 at Swindon
D813 	Diadem 	9 December 1959 	1 January 1972 	Cut up 30 September 1972 at Swindon
D814 	Dragon 	1 January 1960 	7 November 1972 	Cut up 20 February 1974 at Swindon
D815 	Druid 	20 January 1960 	3 October 1971 	Name plates now on a narrowboat
Cut up 13 October 1972 at Swindon
D816 	Eclipse 	17 February 1960 	1 January 1972 	Cut up 22 September 1972 at Swindon
D817 	Foxhound 	9 March 1960 	3 October 1971 	Cut up 10 March 1972 at Swindon
D818 	Glory 	30 March 1960 	1 November 1972 	Not scrapped until 1985
D819 	Goliath 	25 April 1960 	3 October 1971 	Cut up 3 March 1972 at Swindon
D820 	Grenville 	4 May 1960 	2 November 1972 	Cut up 15 August 1973 at Swindon
D821 	Greyhound 	25 May 1960 	3 December 1972 	Preserved, has carried the name Chris Broadhurst in preservation.
D822 	Hercules 	15 June 1960 	3 October 1971 	Cut up 18 February 1972 at Swindon
D823 	Hermes 	6 July 1960 	3 October 1971 	Cut up 19 May 1972 at Swindon
D824 	Highflyer 	27 July 1960 	3 December 1972 	Cut up 18 June 1975 at Swindon
D825 	Intrepid 	24 August 1960 	23 August 1972 	Cut up 27 October 1972 at Swindon
D826 	Jupiter 	7 September 1960 	18 October 1971 	Cut up 21 January 1972 at Swindon
D827 	Kelly 	4 October 1960 	1 January 1972 	Cut up 13 October 1972 at Swindon
D828 	Magnificent 	19 October 1960 	28 May 1971 	Cut up 7 April 1972 at Swindon
D829 	Magpie 	23 November 1960 	26 August 1972 	Cut up 30 January 1974 at Swindon
D830 	Majestic 	19 January 1961 	26 March 1969 	Cut up 22 October 1971 at Swindon
D831 	Monarch 	11 January 1961 	3 October 1971 	Cut up 3 June 1972 at Swindon
D832 	Onslaught 	8 February 1961 	16 December 1972 	Preserved
D866 	Zebra 	24 March 1961 	1 January 1972 	Built at Swindon, lot no. 448. Date of order April 1959.
Cut up 13 October 1972 at Swindon
D867 	Zenith 	26 April 1961 	18 October 1971 	Cut up 30 September 1972 at Swindon
D868 	Zephyr 	18 May 1961 	3 October 1971 	Cut up 7 April 1972 at Swindon
D869 	Zest 	12 July 1961 	3 October 1971 	Cut up 23 June 1972 at Swindon
D870 	Zulu 	25 October 1961 	28 August 1971 	Withdrawn following minor accident damage which was not deemed worth repairing.
Cut up 12 May 1972 at Swindon
== Departmental use ==
=== D818 'Glory' ===
D818 became a "guard loco" at Swindon Works and was repainted from Rail Blue with full yellow ends back into its original green livery. After withdrawal was some hope that it would eventually be preserved, but this did not happen, and the locomotive was scrapped shortly before the works closed in 1985.
=== D832 'Onslaught' ===
D832 was sent to the Railway Technical Centre at Derby where it was used for various research purposes until it too was secured for preservation, while the others were scrapped. D832 was restored to full operational order using many of the parts from D818 and it is doubtful if there would have been enough components available to restore both D818 (which was missing several major items) and D832 without an expensive search for compatible German items, although this scenario became a reality in September 2001 when D832 was fitted with a Mekydro transmission which was sourced from an ex-DB locomotive in Germany.
== Preservation ==
Two warships survive in preservation. 
* D821 'Greyhound' at the British Traction Group
* D832 'Onslaught' at the East Lancashire Railway
== In Popular Culture ==
The BR Class 42 "Warship" is used for the basis for the character Diesel 10 from Thomas & Friends. 
== Gallery ==
File:Crowcombe 832 light engine to Bishops Lydeard.jpg
File:D821 Greyhound 1 (7690443038).jpg
File:BR Class 42.jpg
File:Bishops Lydeard 832 by the water tower.jpg
File:D818 Swindon Works 28.10.82 (9125463394).jpg
Category:Diesel locomotivesCategory:British Rail locomotives
Category:United Kingdom
Category:B-B locomotives
Category:Four-axled diesel locomotives
Category:1955 Modernisation Plan
Category:Warships
Category:Non-Standard Locomotives
Category:Built in 1958
Category:Swindon Works locomotives
Category:Standard gauge locomotives
Category:Locomotives featured in media