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British Rail Class 28
The British Rail Class 28 (Metro-Vick Type 2) diesel-electric locomotives, known variously as 'Metrovicks', 'Crossleys' or 'Co-Bos', were built under the Pilot Scheme for diesel locomotives as part of the British Railways 1955 Modernisation Plan.
These Crossley-engined locomotives were one of two designs built under the Pilot Scheme to use two-stroke diesel engines, the other being the Class 23 'Baby Deltic' locomotives.
The locomotives had a Co-Bo wheel arrangement (a 6-wheel bogie at one end, a 4-wheel bogie at the other) – unique in British Railways practice and uncommon in other countries, although Japan also used some C-B diesel hydraulics. The maximum tractive effort of 50,000 lbf (220 kN) was unusually high for a Type 2 locomotive but, as there were five (not four) driving axles, the risk of wheelslip was minimal.
Work had begun on the Pilot Scheme in 1954 and the first plan for 174 locomotives (all classes) had been produced by October 1954, including 20 of these Metro-Vick Type B locos, although orders were not placed until November 1955. In July 1956 the Type A, B and C designations were changed to Types 1, 2 and 4, making this a Type 2.
The two-stroke engine was chosen as a comparison to the more common four-stroke engines used, and partly as a result of the influence of Oliver Bulleid. The leading manufacturer of such two-stroke locomotive engines was General Motors, but the national shortage of foreign exchange meant that imported engines were unaffordable. Crossley in Manchester had a suitable design in production as a generator set for the Admiralty and had also used it for a class of locomotives in Australia. Although Bulleid had left British railways and moved to Ireland and the CIÉ, he had been impressed by the Admiralty's experience of the Crossley diesel and had already ordered 60 similar locomotives, as the CIÉ 001 Class.
With low-speed Crossley 8-cylinder HST V8 two stroke engines, they represented an experiment in two stroke versus four stroke engines for diesel-electric traction.
The engines had exhaust pulse pressure charging and developed 1,200 horsepower (895 kW) at 625 rpm. There were no valves, and inlet and exhaust were via ports in the cylinder walls. The same engine was originally fitted in the Irish A Class and the Western Australian Government Railways X class. A similar, but smaller engine, the ESNT6 was used in the D3/3 shunters, an 08 with a Crossley engine rather than English-Electric.
Almost from the beginning, the Metrovick's Crossley engines were problematic. They suffered frequent failures and by 1961 the entire class was handed back to the manufacturer for remedial work on the engines and to cure problems with cab windows falling out while running. The cab windows were modified, such that instead of wrapping round to the side, the outer front windows were replaced by a flat piece of glass facing the front only.
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British Rail Class 28
The British Rail Class 28 (Metro-Vick Type 2) diesel-electric locomotives, known variously as 'Metrovicks', 'Crossleys' or 'Co-Bos', were built under the Pilot Scheme for diesel locomotives as part of the British Railways 1955 Modernisation Plan.
These Crossley-engined locomotives were one of two designs built under the Pilot Scheme to use two-stroke diesel engines, the other being the Class 23 'Baby Deltic' locomotives.
The locomotives had a Co-Bo wheel arrangement (a 6-wheel bogie at one end, a 4-wheel bogie at the other) – unique in British Railways practice and uncommon in other countries, although Japan also used some C-B diesel hydraulics. The maximum tractive effort of 50,000 lbf (220 kN) was unusually high for a Type 2 locomotive but, as there were five (not four) driving axles, the risk of wheelslip was minimal.
Work had begun on the Pilot Scheme in 1954 and the first plan for 174 locomotives (all classes) had been produced by October 1954, including 20 of these Metro-Vick Type B locos, although orders were not placed until November 1955. In July 1956 the Type A, B and C designations were changed to Types 1, 2 and 4, making this a Type 2.
The two-stroke engine was chosen as a comparison to the more common four-stroke engines used, and partly as a result of the influence of Oliver Bulleid. The leading manufacturer of such two-stroke locomotive engines was General Motors, but the national shortage of foreign exchange meant that imported engines were unaffordable. Crossley in Manchester had a suitable design in production as a generator set for the Admiralty and had also used it for a class of locomotives in Australia. Although Bulleid had left British railways and moved to Ireland and the CIÉ, he had been impressed by the Admiralty's experience of the Crossley diesel and had already ordered 60 similar locomotives, as the CIÉ 001 Class.
With low-speed Crossley 8-cylinder HST V8 two stroke engines, they represented an experiment in two stroke versus four stroke engines for diesel-electric traction.
The engines had exhaust pulse pressure charging and developed 1,200 horsepower (895 kW) at 625 rpm. There were no valves, and inlet and exhaust were via ports in the cylinder walls. The same engine was originally fitted in the Irish A Class and the Western Australian Government Railways X class. A similar, but smaller engine, the ESNT6 was used in the D3/3 shunters, an 08 with a Crossley engine rather than English-Electric.
Almost from the beginning, the Metrovick's Crossley engines were problematic. They suffered frequent failures and by 1961 the entire class was handed back to the manufacturer for remedial work on the engines and to cure problems with cab windows falling out while running. The cab windows were modified, such that instead of wrapping round to the side, the outer front windows were replaced by a flat piece of glass facing the front only.