The B T H and North British Type 1 Bo-Bo Diesel-Electric Locomotives - British Railways Classes 15 and 16: Development, Design and Demise

By Anthony P. Sayer

The British Railways ‘Pilot Scheme’ orders of 1955 included ten BTH and ten NBL Type 1 locomotives, these being introduced during 1957-61 for use in East London, and on the Great Eastern and London, Tilbury & Southend lines. The BTH fleet subsequently expanded to forty-four, as a consequence of their light axle-loading and the availability of spare manufacturing capacity which BR chose to exploit in their quest to eliminate steam traction. Further construction of these two classes ceased after the fifty-four units, with preference being given to the highly reliable English Electric product which by mid-1962 had proliferated to 128 examples. The NBL fleet survived until 1968, being withdrawn after ten years of indifferent performance. The BTH locomotives followed by 1971, although four lingered on as carriage pre-heating units. Dramatic reductions in goods traffic during the 1960s/70s particularly impacted local trip and transfer freight duties, the ‘bread and butter’ work for the Type 1s, and it was inevitable that the less successful classes were retired from traffic first. This book looks at the short history of these two classes, making extensive use of archive sources, combined with the primary observations of numerous enthusiasts. Previously unpublished information, covering the introduction, appearance design and performance issues of the locomotives, form a central focus, and, allocations, works histories, storage and disposals, liveries and detail differences are covered in the same level of detail as previous volumes in the ‘Locomotive Portfolio” series.

• Language: English
• Publisher: Open Road Integrated Media
• Release date: Dec 30, 2021
• ISBN: 9781526761972

Anthony P. Sayer

Anthony Sayer is a life long railway enthusiast who has been taking pictures since the 1960. He has an interest in the history of early diesels and electric locomotives.Anthony lives in the north east of England and is now retired from the steel industry which was his career for over thirty years.

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Chapter 1

CLASS INTRODUCTION

1.1 Background.

1.1.1 British Thomson-Houston.

British Thomson-Houston (BTH) was a British engineering and heavy industrial company, based at Rugby, Warwickshire, and founded as a subsidiary of the General Electric Company of Schenectady, New York, USA. They were known primarily for their electrical systems and steam turbines. BTH was taken into British ownership and amalgamated with the similar Metropolitan-Vickers company in 1928 to form Associated Electrical Industries (AEI), but the two brand identities were maintained until 1959 when they were consolidated under the AEI banner.

In November 1955, the British Transport Commission (BTC) placed an order with British Thomson-Houston for ten Type A (later Type 1) diesel-electric locomotives as part of their Modernisation Plan (D8200-9). The design and manufacture of these locomotives was a collaboration between several companies. BTH (the main contractor) provided electrical equipment but contracted out the supply of the power units to Davey Paxman (Colchester), the bogies and superstructure to Clayton Equipment (Hatton, Derby); mainframe construction and final locomotive erection was also sub-contracted to the Yorkshire Engine Company (Meadowhall, Sheffield).

A further thirty-four locomotives (in three batches of ten, seventeen and seven locomotives) were ordered in late-1958 and 1959. For these, locomotives mainframe construction and locomotive erection was sub-contracted to Clayton Equipment, although this work was further sub-let to sister company International Combustion (Derby). The ordering of the final batch of seven locomotives ordered at the end of 1959 occurred after the formal consolidation of BTH into AEI.

1.1.2 North British Locomotive Co.

The North British Locomotive Company (NBL) was created in 1903 through the merger of three Glasgow locomotive manufacturing companies, i.e. Sharp, Stewart and Company (Atlas Works), Neilson, Reid and Company (Hyde Park Works) and Dübs and Company (Queens Park Works). Work predominantly involved the construction of steam locomotives for which it earned a very strong international reputation.

In the late-1940s/early 1950s, NBL branched out into diesel traction, with the construction of a Bo-Bo diesel-electric locomotive No. 10800. Further orders were received from the BTC in 1955, including one for ten Bo-Bo diesel-electric Type A locomotives (D8400-9) which turned out to be very similar in design to 10800. In 1959, GEC, Clydesdale Bank and HM Treasury invested in a restructuring programme to facilitate the transition of the company from steam to diesel and electric locomotive manufacture. Ultimately, however, this proved unsuccessful and NBL entered voluntary liquidation on 19 April 1962.

In many ways, 10800 was the precursor to the BTH and NBL Type 1s and it is worth having a brief initial look at 10800 before delving into the histories of the D82xx and D84xx locomotives.

1.2 North British Locomotive Co. No. 10800.

1.2.1 A Brief History.

In 1945, H.G. Ivatt (Chief Mechanical Engineer of the LMS) launched a project for an 827hp diesel-electric locomotive to allow operational comparisons with steam locomotives of similar power as a means for reducing costs. General design work was carried out by E. Fox (Derby), with detailed design and construction undertaken by the North British Locomotive Co. at their Queens Park Works in Glasgow during the period 1948-50.

10800, Derby Works, March 1956. NBL Progressive No. 26413. Note the ladder at the near (No.2) end which gave access to tank filling points; the ladder was a feature on both sides of the No.2 bonnet which housed the train heating boiler as well as fuel and water tanks. Access to the footplate was via steps on the No.2 bogie, and along the footplate to the (very narrow) cab door. Note the absence of windscreen wipers. (Peter Groom)

The design included two bonnets either side of an off-centre cab. The long bonnet contained a Paxman 16RPHXL Series 2 engine, the British Thomson-Houston (BTH) main and auxiliary generators and control gear; the short bonnet housed the train heating boiler, water tanks and fuel tank.

The single cab had duplicate controls within a central desk built out from the No.1 end cab bulkhead. Access to the cab was via doors in the cab front at No.2 end only, one each side of the short bonnet.

The locomotive was carried on two four-wheel bogies each carrying two nose-suspended BTH traction motors. Locomotive and train brakes were both vacuum operated, a feature believed to be unique for diesel locomotives in the UK.

10800 was delivered in May 1950 and, after initial trials in Scotland in late-May and early-June 1950, it was sent to Derby for trials, arriving on 14 June 1950. 10800 entered revenue-earning passenger service on the London Midland region on 20 November, followed by freight work from January 1951. After a short return to passenger duties in mid-1952, 10800 was transferred to the Southern Region in July 1952, where again a mix of passenger and freight work was undertaken. In December 1954, 10800 was transferred to the Eastern Region and between 13 December 1954 and 5 February 1955 it was tested extensively over the London, Tilbury & Southend (LTS) line on various passenger, freight and shunting workings. In February 1955, 10800 was returned to the LMR, allocated to Rugby. 10800’s career was heavily punctuated by extended visits to Works. The locomotive was officially withdrawn in August 1959 (4we 08/08/59) but official records show that it did not turn a wheel during 1959, and probably much of the latter part of 1958 too. Total accumulated mileage was 161,933.

10800 was subsequently used as a static and mobile test bed for a.c. electrical transmission equipment by Brush Electrical Engineering Co. Ltd between 1962 and 1966, deploying a 1400hp Bristol Siddeley-Maybach MD655 engine linked to a Brush-designed a.c. three-phase brushless alternator; rectifiers converted the a.c. alternator output to d.c for control purposes, with inverters supplying a.c. power to the traction motors.

1.2.2 Experience with 10800.

Experience with 10800 in traffic showed that the Paxman engine was not well suited to the challenges of rail traction, lacking the ruggedness of the English Electric engines in the 1600h.p. Co-Co locomotives 10000 and 10001. Major engine failures resulted in long periods out of service for repairs or replacement; days in works for 1951-57 were 18, 156, 160, 239, 68, 233 and 186 respectively. In addition, 10800 was notorious for problems with starting, with the frequent need to resort to ‘towstarting’.

A report on the trials carried out with 10800 on the London, Tilbury & Southend Section entitled Diesel-Electric Locomotive No. 10800. Passenger & Freight Tests, L.T.S. Section, Eastern Region, 13th December 1954 to 5th February 1955 described the trials in great detail; these included freight shunting, inter-yard trip workings, main-line freight services and main-line passenger work. The ultimate rationale for the trials was to get an understanding of potential problems caused by freight traffic and excursion trains as a consequence of the introduction of electric suburban passenger services.

Results showed that 10800 had no difficulties performing shunting, trip freight and main-line freight duties otherwise performed by 3F steam locomotives. Trials on 4F main-line freight duties on the Thames Haven-Ripple Lane route were also handled satisfactorily in haulage terms but were unsatisfactory from a braking point of view where average speeds exceeded 20mph; trials on the more exacting East Ham-Shoeburyness route indicated that only class 3F loads were within its capabilities, but even that required careful handling to maintain proper control.

As far as passenger stock trials were concerned, tests were carried out between Barking and Southend Central. The locomotive with four to six vehicles was able to maintain time, but, with working loads of eight coaches and over, sectional timings could not be maintained in every case; these timings were the same as those for pre-electrification services, and seven minutes faster than those for excursion trains. However, the trial timings were 12½ minutes slower than those proposed under electrification. The Chief Operating Superintendent was insistent that, under electrification conditions, excursion trains must be able to run in turn with electric trains and therefore the results with 10800 were considered unsatisfactory.

The Chairman of the LTS Sub-Committee specified that the operating requirements for a mixed-traffic locomotive over the section of lines included in the electrification scheme should have a capacity to move 350 tons at a maximum of 70mph and 850 tons at a maximum of 30mph. The tests clearly showed that with a train of 350 tons, 10800 could not reach 70mph over favourable sections of line, whilst a loose coupled train of 850 tons could not be hauled safely at a maximum of 30mph due to the inability to stop within the existing braking distances.

The specification quoted by the LTS Sub-Committee Chairman was very ambitious for a single diesel unit and the fact that locomotive 10800 did not fulfil it was not to be taken as a reflection on the locomotive itself. Within its rated power range, the work done during the trial period had been satisfactory and equivalent to a 3P/3F classification. In reality, there was a need for a more powerful locomotive type.

The report also included the following general observations on the locomotive:

•The locomotive was received by the enginemen enthusiastically. The selected drivers found the machine easy to handle.

•As expected, acceleration was very smooth when compared with a steam locomotive.

•During passenger running, the output from the steam heating boiler was insufficient to maintain satisfactory heating on more than six coaches.

•It was found that the boiler was liable to emit thick smoke and sparks when the fuel burning control automatically came into action on the pre-determined working pressure of the boiler.

•The non-circulating water radiators in the driver’s cab were entirely unsatisfactory and required improvement, either by the use of electric radiators or the existing radiators modified for hot water circulation.

•Windscreen wipers should be fitted to the cab windows.

•The vacuum exhausters were insufficiently powerful to ensure a quick release on passenger trains having more than eight coaches.

•During bad weather the horn ceased to operate on account of snow ingress.

•The engine compartment should be provided with drain holes to dispose of any leakage of water or fuel oil.

•An easier method of observing the level of water in the engine radiator was considered necessary.

•The interior surface of the cab should be treated to overcome condensation, and also to give some protection to the driver when coming into direct contact with the side panels in cold weather.

•Provision for storing the driver’s clothing and food should be enlarged and freed from condensation.

•It was considered advisable that all the instruments should be illuminated.

•The fuel transfer pump elbows should be of copper or brass as the existing iron elbows are prone to fracture.

•The width of the cab doors was inadequate.

•The cab windows were a source of danger to a man opening them by gripping the existing hand grip due to lack of clearance.

•The necessity for mechanical maintenance was reasonable.

In ‘Diesel Dawn: The 10800 Story’(British Railways Illustrated, May 2002, R. Fox and M. Kinder), the following comments are made:

‘With the benefit of hindsight it must be said that the retention of 10800 for so many years is quite inexplicable. The constant need for repair, much of it major, and the apparent impossibility of rectifying the problems should surely have become apparent and elicited, if not forced, some decisive action from management long before August 1959. The persistence with trials on the Southern were understandable.....for at that stage there must have been hopes at least that eventually solutions would be forthcoming. But by the end of that period and certainly within a short time of its arrival at Rugby the realisation should clearly have dawned that no improvement had been forthcoming, that the inordinate amount of time that Rugby staff (and others on the system) were having to waste on it, that various re-buildings had already proved abortive and that immediate withdrawal had become the only economically viable course of action. Not the brightest diesel dawn, by a long way.’

1.2.3 Lesson Learnt?

So the key question is: Were the lessons learnt from 10800 applied with respect ordering and design of the NBL (and indeed BTH) Type 1s?

The LTS trials of 1954/55 illustrated a mis-match between the operators’ requirements and 10800’s capabilities, indicating the need for a diesel of at least 1000hp. Fox and Kinder’s concluding comments in their ‘Diesel Dawn’ article were highly critical of the locomotive itself:

‘It should perhaps be mentioned that despite the seemingly endless problems (with 10800), NBL actually built ten 800hp Bo-Bos in one of the ill-fated Pilot Schemes – D8400-D8409 in 1958. How far 10800 was the basis for these is unclear, though there was certainly a close resemblance, in appearance at least. The engine was different though, and the generator and traction motors were by GEC, not BTH. There was one marked similarity – the D8400 locos were subject to constant problems and they too were withdrawn a mere ten years after they were built.’

10800 had already provided the answers to the questions which the Pilot Scheme locomotives were intended to answer. The decision to then allocate the inadequately powered NBL (and BTH) Type 1s to the Great Eastern and LTS areas was somewhat strange, even inexplicable, to say the least.

E.V. Richards (LMS Diesel Locomotives and Railcars, RCTS, 1996) also commented:

‘In view of the lack-lustre performance of 10800, it is perhaps of some surprise that BR persisted with the BTH Type 1, and 10800’s direct descendants, the NBL Type 1s D8400-9 on similar duties.....It would appear that 10800 was not in reality, a proper answer to anything.’

1.3 Order Placement.

1.3.1 D8200-D8209, D8400-D8409 (Ordered: 16/11/55)

The BTC Works & Equipment Committee (W&EC) Meeting (Min. 293, dated 17 November 1954) recorded approval in principle for 160 diesel-electric locomotives at a total estimated cost of £9.28m, 130 for construction by contractors and 30 in BR Workshops. The breakdown of the locomotives to be built by contractors was forty in the 600-800hp range (Type A), eighty in the 1000-1250hp (Type B) range and ten in the 2000-and-over hp range (Type C); locomotives to be built by BR Workshops were split twenty Type Bs and ten Type Cs. The remaining fourteen locomotives of the so-called ‘Pilot Scheme’ fleet of 174 locomotives were constructed with hydraulic transmissions.

The twenty diesel-electric Type C locomotives were approved by the Works & Equipment Committee on 9 February 1955 (Min. 357/40) and authorised by the BTC on 17 February 1955 (Min. 8/74[o]) at a cost of £1.68m and were included in the 1956 Building Programme.

The W&EC Meeting (Min. 388/26) of 23 March 1955 approved the construction of the remaining 140 diesel-electric locomotives provisionally as part of the 1957 and 1958 Locomotive Building Programmes, at a total estimated cost of £7.60m. Advance authority was given by the BTC on 24 March 1955 (Min. 8/142[i]).

Tenders for the 130 locomotives and power equipment for the 30 locomotives to be built in BR Workshops were invited from sixteen contractors, including five overseas companies. Notwithstanding gauge considerations, the tenders received from firms abroad were higher than for comparable British types of locomotives and, therefore, only tenders submitted by the selected British companies were accepted.

The recommended tenders (i.e. those which were considered to best meet requirements) for the 130 complete diesel-electric locomotives to be built by contractors amounted to £8,513,450 and for the 30 power equipment sets for the locomotives to be built in British Railways Workshops, £1,478,600, i.e. a total of £9,992,050 against a total authorised expenditure of £9,280,000, an increase of £712,050 (7.6%).

With respect to the Type A locomotives in the 800-1000hp category, three contractors were nominated for the supply of the required forty locomotives. Details of the selected tender submissions are given below:-

It will be noted that a strict leastcost selection methodology was not applied, ‘the aspect of lowest cost being conditioned by the wish to gain experience with a wide variety of makers and designs’. However, the combination of engine builders and electrical contractors recommended was ‘mainly governed by the selection of the lowest combined tender’ where alternatives were available.

A memorandum dated 29 September 1955 submitted by Chief Electrical Engineer, Chief Mechanical Engineer, Chief Financial Officer, Chief Operating and Motive Power Officer, Chief Commercial Officer and Chief Stores Officer to the W&EC recommended acceptance of the selected tenders at a total cost of £9.92m, together with the distribution of orders between manufacturers. The W&EC approved the memorandum on 12 October 1955 (Min. 517/16). Orders were placed with BTH and NBL on 16 November 1955.

A further Memorandum to the W&EC, dated 2 December 1955, proposed the allocation of the forty Type A locomotives to the 1957 Locomotive Building Programme and asked for approval for the additional expenditure over and above the original estimated costs. Due to time constraints, the W&EC effectively passed the contents of the Memorandum straight onto the BTC for authorisation which was given at their meeting on 15 December 1955 (Min. 8/590).

Official records show that, when ordered, the BTH fleet was intended for use on the Great Eastern. However, between December 1955 and their delivery in 1959 there was a significant change of plan which saw the ten locomotives diverted to the London Midland, specifically for operation from 1D Devons Road. This resulted very largely in response to pressures from Local Authorities on BR as a direct consequence of the passing of the Clean Air Act in 1956, in turn a direct political response to the Great Smog in London in 1952. The area around Devons Road with a significant local residential population was seen as one which could substantially benefit from an early substitution of steam by diesel motive power. The justification to up-grade Devons Road to become the first exclusive diesel depot relied heavily on the benefits of local environmental quality improvements.

The NBL locomotives were allocated for use on the Eastern Region (Great Eastern, and, London, Tilbury & Southend areas) and after construction were delivered there as planned.

Entries in the NBL Sales Ledger documents read as follows:

A Programme for Diesel-Electric Locomotives: North British Locomotive Company document dated 13 February 1956 provided the following introductory details:

D8401 and D8404, 30A Stratford, August 1958. When purchased, the date given for this photograph was incorrectly given as 9 August 1958; D8404 did not undergo mainline acceptance testing at Doncaster until 22 August 1958. D8401, after a return visit to NBL, Glasgow, undertook its second main-line test on 21 August. The locomotives may well have run together from Doncaster to Stratford soon after the 22nd. (Author’s Collection)

D8201, 1D Devons Road, February 1959. Note the residential flats in the background which undoubtedly suffered from very heavy smoke emissions during steam days. Depot building to the left of D8201. (RCTS Archive)

1.3.2 BTH Perpetuation (1): D8210-D8219 (Ordered: 17/12/58)

The intention was for the ‘Pilot Scheme’ designs to be tested over a three-year period with the deliberate objective of determining a limited number of types for volume production commencing 1961/62 based on the operational experience gained. However, facing deteriorating financial results, the BTC abandoned the three year trial period, and accelerated the introduction of diesel locomotives as fast as British production capacity would allow, believing that dieselisation and the consequent elimination of steam would dramatically improve the fiscal position.

Minute 9/384 of the BTC Meeting of 26 July 1956 recorded that:-

‘The Commission … discussed the purchase of additional main line locomotives and agreed that they would be prepared to consider requests for a number of these without further trials, provided that:-

1. There is sufficient technical evidence to show that the type of locomotive desired is fully and without doubt able to meet requirements which are comparable to those in the service for which it is intended.

2. The substitution of the diesel locomotives for steam locomotives is economically justified by the manner in which they will be operated.’

The dangers of giving up the trial period were made very clear by R.C. Bond (Chief Mechanical Engineer) but Chairman Sir Brian Robertson insisted that the Board’s decision was adhered to, and against the specific condition that reliable locomotives were introduced. The Commission also insisted that the number of different designs of locomotives should be reduced to an absolute minimum. This, as already mentioned, was one of the key objectives of the ‘Pilot Scheme’ process but it had now become necessary to recommend the smallest possible number of types without any operating experience having been obtained with the locomotives then on order. The only way of now achieving this was to base recommendations on engineering judgement, knowledge of various firms’ products, and the operating experience of other railways.

As far as the 1958 Building Programme was concerned no Type A (by now Type 1) locomotives were included, building being restricted to fifty-six Type B (Type 2) locomotives (D5020-9, D5320-37, D6110-37).

A Memorandum to the BTC dated 16 May 1957 acted as a cover note for a Report entitled Modernisation of British Railways: Report on Diesel and Electric Traction and the Passenger Services of the Future. This report highlighted ‘the very much more rapid introduction of diesel locomotive traction than had first been intended’, and stated that the Plan for diesel locomotive manufacture up to 1962 ‘sets a production task of magnitude’. It envisaged the ordering of a further 1,889 main-line diesel locomotives during the period 1957-62. The BTC at their Meeting on 23 May 1957 (Min. 10/212) approved the general concept of the extension and acceleration of introduction of diesel traction as contained in the report, but without any commitment to the exact pace of extension, stating that:

‘The Commission would be prepared to go further than they have already gone in regard to ordering diesel main-line locomotives, in spite of the risk of unsatisfactory performance in the early stages, if the Regions presented them with a limited number of firm plans for their use in specific areas [so-called Area Schemes], containing as clear a justification as possible’.

The Commission again asked that the question of limiting the number of main-line diesel locomotive types be specifically addressed, and to advise on what was practicable. The Report Main Line Diesel Locomotives: Limitation of Variety (R.C. Bond & S. Warder, 26 July 1957) was produced in response to this request. The principles used in the Limitation of Variety report governing the selection of locomotive types for ordering, beyond those already ordered, were (i) reliability, and, (ii) as much standardisation as British production capacity would allow.

On the basis of these key considerations, the recommendation was that any diesel-electric locomotive orders placed in the 1959 and subsequent Building Programmes should be limited to the following types (plus the BRCW Type 3s for the Southern Region which were seen to be a special case), subject to the phasing of the Regions’ specific requirements and manufacturing capacity:

English Electric and Sulzer engines featured strongly. It was considered that English Electric had the largest experience and productive capacity of any British manufacturer and had the resources to ensure the delivery of a reliable product, whilst the Sulzer engine was the best known and widely used product outside of the USA, and was recognised for its excellent design and workmanship. Paxman engines were proposed as a reserve type.

Subsequent discussions with industry soon showed, however, that it was not possible to strictly adhere to these recommendations; as a consequence, and to meet BR’s latest forecast demands for diesel-electric locomotives and to fully capitalise on available production capacity, the use of ‘non-recommended’ contractors became essential. Over the subsequent two to three years, there was substantial ordering of equipment of ‘non-recommended’ Types, from English Electric (Type 4s) and Brush (Type 2s) in particular, but also from British Thomson-Houston.

At the BTC Meeting on 19 September 1957 (Min. 10/406), the Commission approved, in principle, a 1959 Building Programme of the order of 750 to 800 locomotives. It was recognised that this was a large requirement and that available production capacities may dictate some deferral into 1960. However, a subsequent capital investment restriction in late 1957 severely limited the purchase of locomotives for delivery in 1959 and it was, therefore, impossible to take full advantage of the building capacity for main-line diesel locomotives available in that year.

The revised 1959 Building Programme was, therefore, restricted to eighty-four Type 2 diesel-electric locomotives (plus shunting and electric locomotives); all of these Type 2s were to be built in BR Workshops employing Sulzer engines (subsequently D5030-D5113). The W&EC approved the building of these locomotives at their meeting on 22 January 1958 (Min. 1110/20) and authorised by the BTC on 13 February 1958 (Min. 11/53). The remaining requirements were deferred into 1960 and 1961. Contractors were, however, invited to tender in anticipation of these later Building Programmes.

The financial situation eased during 1958 and as a consequence there were two Supplements to the 1959 Building Programme, with locomotive types selected on the basis of the tenders now received from contractors. The First Supplement (ninety locomotives), including no Type 1s; however, the Second Supplement (for forty-nine locomotives) included ten Type 1s.

Contractors had previously offered available capacity for the construction of locomotives during 1959; in the Type 1 range, English Electric had offered thirty locomotives and BTH ten, both of designs already being supplied.

A Memorandum to the W&EC dated 3 November 1958 proposed acceptance of these offers given the additional capital expenditure now permitted. However, in the preamble, the authors of the Memorandum recognised that:

‘… the Regions have paid