By 1958 it was apparent to those at the BRB dieselisation office and the fleet controllers of the ECML that the wieght and lower power of the EE 16 SVT and Sulzer 12LDA delivered locomotives was not sufficient to replace the performance of the 'pacific' steam locomotives. "3000hp under the bonnet" was the rallying cry.
Of course EE had undergone a purely private venture in creating the 'Deltic' prototype, which fullfilled the design specifications and had put in some tremendous trial runs on the W&ECMLs and elsewhere. An order for 34 was placed for the ECML with a later follow up of 12 to be utilised on NE to SW through trains to avoid the need to change locomotive, and some of the fleet was used on the WCML northwards from Crewe.
However BRB were under some internal and political pressure not to allow any one manufacturer to completely dominate the order scheme for type 4 and type 5. The longevity of both locomotives and manufacturer presence in the market were both still unkown quantities. Deltics had been promised a 10 to 12 year life time with parts recoverable for the D6700 fleet or re-engining options to be considered. They came of course to last longer and be joined by their Type 6 cousins, the super deltics which are now entering their fourth decade, be that with new PUs. Brush and BRCW were approached and decided to cooperate on a rival type 5 plan, producing two prototypes based upon the Brush variant of the type 4.
The main technical problem was that as of 1960 it was known by EE and brush that voltages involved in producing over 2.2kw from the current generators would require a cleanliness not realistically available in a rail environment. EE solved this by using two PUs-generator set ups while brush used a higher amp circuit capable of an estimated 1.8kw.
So brush decided upon utilising two generators with an extended version of the production 12LDA. Taking basically two of the type 3 8 cylinder engines and casting a twin bank arangement. This unti was designed in Switzerland but built in Germany, at reputably huge expense. The idea was to either mount the generators laterally adjacent or at either end. BRB loading gauage in terms of width and air-draught would not allow for the cramped single end set up.
Placing a generator at either end of the engine came with a penalty in terms of space. Furthermore the single generator/s usually resides in the 'clean end' (or centre) and is bathed in filtered air as it self-cools under rotation. Requiring two 'clean ends' would mean creating a yet longer locomotive and to keep costs down the two initial prototypes were built on the current 1CoCo1 platform of their body-snathced victims the peaks.
Brush and BRCW overcame this by creating a clean air culvert system which supplied the two generators with air flow and maintained them under 'positive pressure' while in operation and also on start up and for one minute after shut down. Hence the locos were known as "blowers" amongst other less sulubrious nick-names. The generators were inside shells with vents which were closed under null pressure, some of which being operated thermostatically. Basically fans located at either side of the PU, low on the body and away from exahust fumes, forced air over a oil wet surface seive filter and through the channels towards each end of the PU. These filters were to some degree self-cleaning and had three 'phases' , one being washed and one dried at any point in a given engine hour cycle. They were slid over one another hence avoiding any 'down time' in the filtering process whilst the flow-demand paddle would simply request more pressure upon them going momentarily into double depth. This electro mechanical system worked well but was abandoned later.
It took some time for the twin bank engine prototypes to be constructed with one block entirely rejected on grounds of a metalurgic fault. However by 1962 the PU, electricals systems and control equipment had all been tested on static generation beds linked to bogies with modified traction motors and gearing. The engine was trialled at 3450 hp @900rpm, but to keep servicing levels in line with the type 3 8lDa fitted locos which were in service, the PU was regulated down to 750rpm acheiveing a mechanical 3200hp, a miserly 100hp short of the EE competition. Coupled to this was the further weight handicap of the heavy 16LDA and the 1CoCo1 chasis/bogie set up. To add to their risk of not pleasing the clientel with a judicous delivery time, the BRB responsible buyer descided to request the latest design 'flat front ends' as sported by the "Lion"prototype of the same origin. The alliance would not have bent with the wind if that had known that the BRB had just placed an order for 66 'DP2' locomotives to replace the d1 series on fast passenger and work north of crew, and on NW-NE expresses and the Holyhead-london route. However bend they did and created cabs at the ends of the mammoth 1CoCo1s, making for an incongrous blend of the first generation and that one emerging.
It was not before early 1963 that the two prototypes entered service and BRB ECML had already taken up the full order of deltics plus the option for 12 based upon potential resale post electirfication back to the supplier. This set a somewhat bleak scene for BRCW but BRB saw fit at this point to cancel further orders of type 2s and set many of the relatively reliable 'peaks' to work on frieghts and secondary passenger services. This meant space on the midlane and ECML at least for a type 5 and brush could allow their offering to be evaluated here.
To overcome issues with overheating traction motors, brush had made a major compromise in their use of voltage/ampage and increased voltage across the circuit. The locos were designed for maintained high speed running and rapid acceleration through the range so they had set five field diversions, the first characteristaclly low down to allow for a very heavy train to be started ( over 1500tonnes was tested!) . They had a system to flip the generators out of circuit only momentarily hence allowign the mechanical RPM to only subside to 30 to 40 % max running range. THis undoubtedly played into the fact that the locos had very good service interval with engine assesments at least double that of major service requirements on the deltics.
By this time the midlane line had gone over to ETH coaching stock and this also included wider range trains such as the St Pancras-liverpool and Holyhead via Manchester, the Edinburgh via Nottingham and Leeds and the Cross london services to Dover, Brighton and S'ton/portsmouth. In a bid to appease the patience of BRCW/Brush the BRB allowed the locomotives to be redesigned to avoid the requirement for the couple of tonnes of boiler equipment plus the extra water tank and the producition run of the twin bank 16 LDA was several tonnes lighter. Thus a Co Co locomotive was acheivable with a total wieght of under 125 tons. Brush/BRCW learned fromt he Lion and the concurrent order for the brush type 4 ( brush buiying BRCW out at around this time) and applied further weight and space saving features into D12000- "EAGLE", the first production model which was backed by an order of 32 further examples.
The blowing-budgies as they were nick-named for their clean air circuit sound and the eagle emblem the first six carried, were a great success on the midland line and were able to match delticcs on the ECML and even exceed their speeds under mointored trials of 105mph and 112mph down hill. These were not within the originaly manufacturer warranty and Brush refused to extend this, probably with an eye to holding a marketing edge for their potential 'type 6' offering already under design in 1965- the prototype 'Falcon' for which the steel chasis had already been laid with a view to 125mph operations in the UK and the growing foreigh market tired of the lack lustre GM performance in locomotives.
One side effect of the purchase of these was that the 8 cylinder unit was chosen to re-engine firtslyt the entire class 26 then class 27 fleets, due to it'æs standardisation in the 'class 53' and class 33s. This was done so on a basis where ETH stock could be allocated or just when the 6LDA could be flogged off to shipping or static use! Some of the class 25 fleet underwent conversion in the early 70s with a view to replacing the western region 'Hymeks', somethign which never eventually happened until some decades later.
BRB were confident to cascade power down the routes to allow for the decimation of the unsuccessful type 2s below 1350hp at least. Type 3 would become the mainstay of semi-fast stopping services and medium distance such as Nw- East England etc, as well as having mixed traffic capacity / availaibilty at shed. Lower powered type 4s would work frieght and longer distance stopping services, and this included the peaks outside MML service and the use of 'permanenlty' paired D200s. General 2500hp plus co-cos would work the typical D1-D399 services on main lines and express freight.
In ScR, the lack of ETH stock required the production of the 'drain pipe' boiler-compressors which to some extent solvedthe problem and after some intiial disatarous teething problems, prove more reliable than the earlier types and far more economical to run. These were long slim units with a core about the width of just a drain pipe and featured recompression i.e. steam was sent back along the outer heat jacket to catch some more therms before whisking off to heat bums on seats. The slimness meant they could lie along the side of the engine towards the no 1 end and their excellent heat recovery and insulation ensured only slight compartment warming, which was not unwanted in the winter application they found anyway!
The Type 6s .
Towards the end of the middle of the 1960s, BRB had a desire to match the best of foreign performance and that of the best runs by the Gressly Pacifics. 125mph operations would require between 4 and 5ooobhp to haul a 600 tonne train. Given tight supply of steel and labour, single rather than double headed or end to end locomotives were of preference. Brush had already entered the successful Falcon initiative, committing to this in 1964 with the patenting of various features of their traction and compact space alternator. EE had prepared a spare deltic body shell with turbo charged 15 cylinder engines at 2250hp each in 1964-5, although this was purely a static test. Further to this they were prepared to enter a new non flash over generator rated at 3kw and powered by 18 cyclinder variants of either the EE newton v18 or the paxman v18 valenta and later ventura with the hope of matching the 10 000 hour service interval acheived by the DP2s and their cousins the D600s.
Also BRB could see the need to displace the frquent use of paired locomotives to supply motive power to supplement the ill fated first and second generation multiple untis and the various type 2 classes now deemed unstandard and outright inadequate compared to the 'tank' and small tender steam power they replaced. This cascade down the tree meant a redeployment of type 3s to more passenger and lower HP type 4s to largely freight: The aim of this was to speed up the replacement of steam and deliver improved time tables over 'kettle power' and aslo replace the disasterous generation 1 DMUs from mainline useage. These bus engined heaps were being converted to non driven coching stock at the rate of three units a week by 1967!
BRB had shelved plans for the ECML, midland and Bristol route electircation plans and concentrated on the WCML. They wanted to reallocate the dp2 and subsequent dp3 fleets away from the WCML to finally kill off the wisp of steam by 1968 on all other major express routes, picking up cross country ventures into ScR, Southern and western regions. This would also release the numbers at a higher rate if a 4000hp replacement could come into play as single locomotives, replacing the D200s and D6700s used in pairs prior to full delivery of DP2 and first numbers of the Dp3 D600s ( later class 54 and 50 respetively)
Under pressure to maintain a serious competitive supply chain in the UK, with the demise of many of the former steam builders and others like vikers, the government forced BRB to split the original order for the "proven" superdeltic with the 4400hp kestrel fleet. The order was split 25 :25.
Now the superdeltics had an odd course of fate. Firstly turboing the engine did nothing to increase service interval towards that of the CSVT or LDA or LVA engines. They were planned for 2700 hours between strip downs despite the reduction in one bank of cylinders to 15, and some other stregnthinening and maintainence frenignly modifications over the 1950s 18 cylinder units. Later in operation BR WCML NW operations were acheiving 5000 hours out of the new kestrels while the deltics were still "running in under manufacturer warranty and close supervision' . Often they ended up running on one PU alone, yet still commanding 110mph ! This operational ability was taken into good use during the fuel crisis of the subsequent young decade, when the second unit would be switched off going down shap and beatock and for the secondary extended routes of Perth, Inverness, fortwilliam and aberdeen as well as their optional use on the stranraer and holyhead routes.
The Dp2 order was fully delivered by 1965 and all units fully commissioned or rectified under warranty by 1966. The latter which would have taken them into over 200, was switched over to the slab ended dp3- the D600s and the prototype, in effect 50 050, was delivered in 1966 with others being laid down to the somewhat over complex specifications set by the customer.Later they as said became class 50 whilst the Dp2 fleet were reclassified class 54 to represent their close similarity to deltic 55, and later it fitted with their revised final power rating.
The kestrel prototype was also being trialled under private venture late in 1966 and of course was subsequently ordered along with the superdeltics. These 'big brushes' started displacing Brush type 4s from their new build and rectification programme at brush a fact which was hard to hide from the BRB purchasing committee. However the promise of single power units releasing pairs of D200s, D6700s and the planned use of D600s in pairs by 1969 kept their fears at bay and after the first 12 were laid, following construction was more phased in with the new build, derating and re-egining of the two type 4 variant classes.
Super deltics, or just "the supers" as they were called, came in as "prototypes" as before for Dp3s, really in fact being pre-production units. This was somewhat risky but in many respects EE were rightly confident in terms of power delivery, performance and reliability between service intervals. In actual fact by the time in 1967 static rolling road trials had been run on "DP4 no.1" there were three sisters nearing completion at Newton-le-Willows. Two were delivered in what was really a pre-prepared commissioned state each with 1000 loco hours and probably more PU hours from the non loco test pans.
These were available for trials in late august-september although EE had had the same priveledge as brush in having ready access to test trains, tachograph coaches and light locomotive runs. At this time there were a further four actually on the tracks under EE private supervision/ownership, and the whole prototyping issue became a bit of a farce. BRB had ordered them on the back of access to the static trials on 55033 with turbo engines and on the good reputation of the Deltics, DP2s and other variants.
By March 1968 the super deltic order was ratified although 8 units were actually ready for service on the 20th of march insitgation of contract for their actual build! A further six were laid down that year, but the DP3 order suffered and given promising service interval and 5400 hp on express services in 1967, with a shorter commissioning time than the super deltics at 6 months rather than the rather luxurious 14 months for the supers. The push to replace steam had to be balanced with actual full availability of reliable diesel power for express services and WCML area secondary and releif services would utilise the ever growing number of type 2 and 3s made available by the deminishing number of post beeching mixed freights with the move to road haulage.
Kestrels were delivered at a pace with a shorter pre-delivery trial / rectifcation and also a wise non time stipulated commissioning. It was based on key indicators, repeat tests and a brush / Derby works service at 500 engine hours ( which was between 1000 and 2000 actual PU hours). Brush had a secret option from BRB central to supply more than 50 kestrel type locos in addition to the 25. It has been speculated that these would have either supplemented diesel hydraulic operations in the west, hasting their demise ( wishful centralised thinking in the mid 60s) or to actually replace much of the ECML deltic fleet. This was not maybe relevant for Brush who needed the hard cash from the 25 units to supplement the huge re-enigining, de-rating and cancellation of the Type 4s- the class 47 and 48. They pushed on with the kestrelas and all were at least built by 1968 Q3, and payed for by mid 1969.
Super deltics were as mentioned delivered in a tight group of 8 and then a further 6 in 1968 before a gap to allow Newton and RSH(derby) Ltd to finalise the DP3 order, deliver the final D700 order and begin the 'super syphon' project. 14 was probably in hindsight enough given good availability of Kestrels, the planned service interval of the Dp4s and the continuing use of pairs of D600s on the route. However EE had planned to take full advantage of the manufacturer inspection ( D exam) necessitated as an option in the warranty agreement. This meant that depsite a planned service interval at the now trained Crewe Diesel depot and Crewe and Doncaster works, EE could take them out of traffic and secure payment for the remaining 9. BRB had already scaled down type 4 mixed traffic orders for both the DP3s and the disappointing Brush Type 4s, favouring the introduction of two freight dedicated classes -the class 43 and the class 38 super-syphons which were based on the now proven EE CSVT and Co bogie but at a 10,000 hour service interval.
In the end the last two superdeltics were delivered in 1970 and actuall the bill came from GEC Group PLC to BRB.
Power Unit ( diesel engine) Life Cycle Options from EE (GEC)
EE took a wise course at about the same point they delivered the finally "DP3s" and the first "Dp4s" i.e. super deltics. . With D400-D590 being DP2s they offered the 'DP3s' later class 50s with leased PUs which could be subject to anticpated upgrades in PU and also the fall of patents relating to alternators. They offered an option to review PU with a view to either retro upgrade of parts ( as ill fatedely happend on the class 50s at a 3000hp rating) or complete new pus ( as worked well onthe DP2s with 3300hp) . This was also applied to the Super deltics, and much to the chagrin of many a commentator and entusiast the dp4s were retro fitted with either twin v8 Ventura producing 2000hp a peice at 1650 rpm (with a service interval of 6000 hours ) or the V16 by this time RK engine with quad turbos at 3450hp and an interval of 8000 hours. They are currently stored servicable awaiting an SRA approval for sale abroad or disposal as they are still considered non standard by their now private owners.
By 1980 all superdeltics bar one had their engines replaced to form class 61 and 62 respectively. The one remaining unit was bought by a wealthy millionaire who was mad about them and continous in it's semi -mainline, semi preserved status toiday despite enviromentalist actions agaisnt the 'summerset smoke cloud'
But the ignomosity of having the original PU ripped out to a lower HP replacement was not left for the superdeltics. In the mid 1980s the kestrel fleet was brought back into private ownership as the first example f such. they were systimatically re-engined with the same 3300 hp unit as the heavy class 56s and utilised on the holyhead route replacing class 40s and peak classes on this and other services. 4 Locos of the 20 were lost to cannabilisation while a further 8 were sold to austrailia and refitted with what became the later class standard- the 16 venturea (VP185 effectivley) at 4400hp. In 2000, it was decided that the body and other electro mechanicals were sutiably robust for the remainder of the fleet to be fitted with v16 VP185s at 4400 hp and this was completed in 2004 with the locos now working alongside the latest class 69s of the same PU on the holyhead drags, the bristol and cardiff drags, the midland line, the channel tunnel railhead to leeds via the midalnd route and assorted other trial trains.
Re-engineing
In the 1970s a major repair programme was undertaken on the class 50s and 53ss as an opt-in to the contracts set by EE and now honoured by GEC. The electrical giant extended the option tie to Rustons upon divestment from the group. Meanwhile this new freedom as a demerged company and the success of the kestrel class from Brushg lead to a parralell order for the class 56 freight dedicated fleet. This too was optioned and the class is now well into what is expected to be it's fional phase with v16s in about 2/3s of the fleet at some 3450, most 3800 and 18 toton allocated at4350 hps. The final third of the class were fitted with the twin turbo v12 RKe so successful in the class 54. These run as a freight dedicated cousin in depots with a mixed or passenger traffic allocation of the now unquituous Brush / Ruston Class 54 "mini dubber". For example Motherwell and laira both have small allocations. It should be noted that about 35 class 56s have succombed to becoming parts bins from the original fleet, most of these being the early romanian built indivivuals locos.
The sixteen remaining Dp2s and the 8 remaining class 50s have all been fitted with leased v12 engines at 2700 and 3000hp respectively. This was commenced at the time 'thuird and forth' generation DMUs showed their weakness in reliability and resutling capacity to deliver the uk punter. Thus were a limited number of these 'non standards' saved from the cutters torch whilst som of their brehtrin are now active in preservation adn spot hire.
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