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Specifications
Specifications
Configuration:;
• UIC	Bo′Bo′
• Commonwealth	Bo-Bo
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Wheel diameter	3 ft 7 in (1.092 m)
Minimum curve	3.5 chains (70.41 m)
Wheelbase	28 ft 6 in (8.69 m)
Length	42 ft 6 in (12.95 m)
Width	8 ft 8+1⁄2 in (2.654 m)
Height	12 ft 8 in (3.861 m)
Loco weight	68 long tons (69 t; 76 short tons)
Fuel capacity	400 imp gal (1,800 L; 480 US gal)
Prime mover	Paxman 16YHXL
Displacement	78.4 L (4,780 cu in)
Generator	GEC WT 881 (plus GEC auxiliary generator
Traction motors	4 x GEC WT 441, nose suspended, with single reduction gear drive
Cylinders	16
Cylinder size	7 in (178 mm) bore ; 7+3⁄4 in (197 mm) stroke
Transmission	Diesel electric
MU working	● Red Circle
Train heating	None; through steam pipe
Train brakes	Vacuum

Type and origin
Type and origin
Power type	Diesel-electric
Builder	North British Locomotive Company
Serial number	27671–27680
Build date	1958
Total produced	10

NBL Type 1
British Rail Class 16
NBL Type 1; British Rail Class 16
	No. D8403 in green livery with all-yellow front end at Stratford MPD in July 1966
Power type
Type and origin
Power type	Diesel-electric
Builder	North British Locomotive Company
Serial number	27671–27680
Build date	1958
Total produced	10
Configuration:;
Specifications
Configuration:;
• UIC	Bo′Bo′
• Commonwealth	Bo-Bo
Gauge	4 ft 8+1⁄2 in (1,435 mm) standard gauge
Wheel diameter	3 ft 7 in (1.092 m)
Minimum curve	3.5 chains (70.41 m)
Wheelbase	28 ft 6 in (8.69 m)
Length	42 ft 6 in (12.95 m)
Width	8 ft 8+1⁄2 in (2.654 m)
Height	12 ft 8 in (3.861 m)
Loco weight	68 long tons (69 t; 76 short tons)
Fuel capacity	400 imp gal (1,800 L; 480 US gal)
Prime mover	Paxman 16YHXL
Displacement	78.4 L (4,780 cu in)
Generator	GEC WT 881 (plus GEC auxiliary generator
Traction motors	4 x GEC WT 441, nose suspended, with single reduction gear drive
Cylinders	16
Cylinder size	7 in (178 mm) bore ; 7+3⁄4 in (197 mm) stroke
Transmission	Diesel electric
MU working	● Red Circle
Train heating	None; through steam pipe
Train brakes	Vacuum
Maximum speed
Performance figures
Maximum speed	60 mph (97 km/h)
Power output	Engine: 800 hp (597 kW); At rail: 627 hp (468 kW)
Tractive effort	Maximum: 42,000 lbf (186.8 kN)
Brakeforce	31 long tons-force (310 kN)
Operators
Career
Operators	British Rail
Numbers	D8400–D8409
Axle load class	Route availability 4
Retired	1968
Disposition	All scrapped

The British Rail Class 16 also known as the North British Type 1 was a type of diesel locomotive designed and manufactured by the North British Locomotive Company. A total of ten were produced, these being numbered D8400-D8409.^[1]

The type was ordered by British Railways (BR) as an element of the 1955 Modernisation Plan. The design was largely derived from North British's earlier prototype locomotive, designated No. 10800, produced during the late 1940s; it also incorporated several engineering approaches common to steam locomotives, the company allegedly having difficulty transitioning to the new traction format. Akin to several other Type 1 designs, they were relatively compact locomotives that were intended primarily for local freight traffic. The performance of the type was found to be lacking in comparison with its peers, thus the potential for follow-on orders evaporated and no further examples were constructed beyond the original batch. The Class 16 shared numerous design features with those used on subsequent locomotives by the company, particularly the British Rail Class 21 locomotive.

Background

In less than a decade following the formation of British Railways (BR), substantial changes were being made. Under the 1955 Modernisation Plan, a long-term strategy of replacing steam locomotives with a combination of diesel locomotives and electric locomotives was adopted, with the former being largely intended as an interim measure for most areas ahead of widespread electrification of trunk routes. There was also a strong political desire to support British manufacturers in transitioning towards the design and production of these favoured forms of traction. Due to a lack of expertise, this often involved the pairing of traditional locomotive manufacturers with various firms within the electrical sector, even though the latter typically had very limited experience of the railways.^[2]

In accordance with these policies, BR ramped up its efforts to convert its fleet, placing numerous orders within a short timeframe for diesel locomotives to several different specifications with various manufacturers. On 16 November 1955, a small order for ten Type 1 freight locomotives was placed with the North British Locomotive Company.^[3] Under BR's 'pilot scheme', such batches were intended for evaluation purposes under competitive conditions against rival designs in which the better models would receive follow-on orders.^[3] In the Class 16's case, this included the British Thomson-Houston Class 15 and English Electric Class 20

Construction

Distribution of locomotives,
October 1967^[4]
Code	Name	Quantity
30A
30A	Stratford	10
Total:		10

The design drew heavily upon North British's earlier prototype locomotive, designated No. 10800, which had been developed between 1947 and 1950. Having been ordered originally by the London, Midland and Scottish Railway prior to its absorption into BR, No. 10800 was designed for use on branch and secondary lines; according to railway historian Rodger Bradley, this early British diesel locomotive functioned not only as the direct predecessor of the Class 16, but can be more broadly considered to be the forerunner of all BR designs orientated towards this type of work up until the 1980s.^[3]

The design also shared some similarities with the contemporary British Rail Class 15; both locomotives adopted the road-switcher layout that had been rapidly becoming the standard approach on the railways of both North America and Australia at the time; they were also both powered by an 800 hp (600 kW) Paxman 16YHXL prime mover.^[2]^[3] However, the North British design suffered a major setback as a result of external policy decisions; while the company had decided to approach the new era of diesel traction by specialising in hydraulic transmissions in partnership with the West German industrial interest Voith, BR planners had decided to favour electric transmissions instead, putting the firm at a competitive disadvantage to those locomotive builders that had opted for this transmission system.^[3]

The locomotive's construction was based on fabricated mainframes that ran the entire length of the locomotive; this practice was inline with traditional steam locomotive designs.^[3] According to Bradley, North British found it difficult to translate their steam engineering skills to the newer diesel and electric traction designs.^[3] The mainframes were carried on a pair of four‑wheeled bogies and supported the single drivers cab and the superstructure in which the engine and other apparatus was accommodated within. Both the electro‑pneumatic control system and traction motors of the Class 16 were identical to those used on the subsequent British Rail Class 21 locomotive, albeit with the traction motors being downrated to 152 hp and 420 rpm.^[3] As they were intended exclusively for hauling freight trains, they were not equipped with train heating boilers.^[3]

The original delivery schedule agreed between North British and BR called for the delivery of the first locomotive to occur 21 months from the date of settlement of technical details, resulting in an intended delivery date of August 1957. However, there was considerable complications encountered during the type's construction, which has been typically viewed as not unexpected in light of a general lack of experience with mainline diesel traction on Britain's railways, and as such did not come as a surprise to many officials at the time. The first Class 16 locomotives did not emerge from North British's Queen's Park Works in Glasgow until the summer of 1958, roughly one year behind schedule.

Operation

Upon their completion, all ten Class 16 locomotives (numbered D8400–D8409) were delivered to Devons Road depot, Bow, North-east London on the London Midland Region of British Railways between May and September 1958. There, the type underwent evaluation against the rival designs, but were promptly relocated to nearby Stratford depot on the Eastern Region, where they remained for the rest of their operating lives.^[3] The allocation of all ten locomotives in October 1967 was Stratford.^[5]

The results of the evaluation were not positive for the type, thus no further Class 16s were ever produced. While the Class 15s also suffered problems with the Paxman engines, these were worse on Class 16 because inadequate ventilation resulted in frequent engine seizures.^[3] Another problem was coolant contamination of the oil, due to cylinder head failure^{[clarification needed]}. They were fitted with a non-standard type of electro-mechanical control equipment (coded "red circle" by BR) which was prone to failure, and they could not operate in multiple with locomotives fitted with the more common electro-pneumatic ("blue star") controls.^[3]

Withdrawal

Being both non-standard and fairly unreliable, the locomotives were an obvious candidate for early withdrawal despite barely being ten years old as BR planners were coming to this conclusion.^[3] Accordingly, they were all withdrawn between February and September 1968; all ten Class 16s had been cut up for scrap by the end of 1969.

References

Citations

^ "NBL Ltd 16 Bo-Bo". brdatabase.info. Retrieved 7 December 2020.
^ ^a ^b Bradley, Rodger. "BTH Type 1 Bo-Bo – Happy 60th Birthday". twsmedia.co.uk. Archived from the original on 2 December 2020. Retrieved 7 December 2020.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Bradley, Rodger. "The Last North British Type 1 Diesel". twsmedia.co.uk. Archived from the original on 2 December 2020. Retrieved 7 December 2020.
^ British Rail Locoshed Book. Shepperton: Ian Allan. February 1968. p. 31. ISBN 0-7110-0004-2.
^ British Rail Locoshed Book. Shepperton: Ian Allan. February 1968. p. 32. ISBN 0-7110-0004-2.

Sources

Clough, David N. (2005). "Pilot Scheme Prototypes of Type A/Type 1: NBL D8400 series (later Class 16)". Diesel Pioneers. Ian Allan. pp. 44–50. ISBN 978-0-7110-3067-1.
Stevens-Stratten, S.W.; Carter, R.S. (1978). British Rail Main-Line Diesels. Shepperton: Ian Allan Ltd. ISBN 0-7110-0617-2.
Sugden, S.A. (April 1994). Diesel & Electric Loco Register (3rd edn). Sheffield: Platform 5. ISBN 1-872524-55-9.
Grindlay, Jim (2006). British Railways Locomotive Allocations 1948-1968 (Part 6 - Diesel & Electric Locomotives). Troon: Modelmaster Publications. ISBN 978-0-9544264-6-0.