LNER Cock O The North The locomotives were designed by Nigel Gresley to haul express trains over the difficult Edinburgh to Aberdeen section of the London and North Eastern Railway. In the design Gresley was influenced by recent French practice, in particular passenger locomotives of the Paris à Orléans railway. The first locomotive of the class, No.2001 Cock o' the North, was introduced in 1934. It was built at Doncaster Works, with Lentz- type[citation needed] rotary-cam actuated poppet valve-gear supplied by the Associated Locomotive Equipment Company, and a double-chimney Kylchap exhaust, each chimney using four nozzle blastpipes. The chimney system was designed to take different fittings to allow experimentation with exhaust arrangements.[citation needed] The boiler barrel was of the design used on Gresley Pacifics, fitted to a larger firebox. The front end design was of the same form as the Class W1 locomotive, No. 10000, derived from Dr. Dalby's wind tunnel research, and the attached tender was of the standard design used on Gresley Pacifics. The P2 introduced a wedge-shaped cab front end, designed to give a better view forward. The same design was used on the later A4 and V2 express engines. No. 2001 was fitted with a Crosby chime whistle which Gresley had obtained from Captain Howey of the Romney, Hythe and Dymchurch Railway, and which was originally intended for one of that railway's Canadian Pacific style locomotives. The second locomotive of the class, No.2002 Earl Marischal was completed by 1935, also at Doncaster, and was fitted with Walschaerts valve gear, as used on Gresley Pacifics, and had a greater superheater heating area of 776.5 sq ft (72.14 m2), obtained by using larger diameter fire tubes. At low cutoffs smoke clearance on No.2002 was unsatisfactory: wind tunnel experiments led to an additional second pair of smoke deflectors being fitted inward of the first. No. 2002 proved to be more efficient than 2001, due to a lower cylinder clearance volume and because the stepped-cam cutoff modifications made to No. 2001 reduced economical working relative to the infinitely variable cutoff of No. 2002. Consequently, the following locomotives were built with piston valves. By June 1936 the third engine had been produced: No. 2003, Lord President, based on the design of No. 2002 but with the external design modified to resemble the Silver Link locomotives. (see LNER Class A4). The locomotive weight was reduced to 107 long tons 3 cwt (240,000 lb or 108.9 t).[15] The wedge-shaped front was found to lift the engine's smoke clear of the driver's view;[15] No. 2002 was altered to this form in 1936, and No. 2001 in 1938. Three further locomotives, Mons Meg, Thane of Fife and Wolf of Badenoch, were under construction at Doncaster in 1936.
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LNER Cock O The North The locomotives were designed by Nigel Gresley to haul express trains over the difficult Edinburgh to Aberdeen section of the London and North Eastern Railway. In the design Gresley was influenced by recent French practice, in particular passenger locomotives of the Paris à Orléans railway. The first locomotive of the class, No.2001 Cock o' the North, was introduced in 1934. It was built at Doncaster Works, with Lentz- type[citation needed] rotary-cam actuated poppet valve-gear supplied by the Associated Locomotive Equipment Company, and a double-chimney Kylchap exhaust, each chimney using four nozzle blastpipes. The chimney system was designed to take different fittings to allow experimentation with exhaust arrangements.[citation needed] The boiler barrel was of the design used on Gresley Pacifics, fitted to a larger firebox. The front end design was of the same form as the Class W1 locomotive, No. 10000, derived from Dr. Dalby's wind tunnel research, and the attached tender was of the standard design used on Gresley Pacifics. The P2 introduced a wedge-shaped cab front end, designed to give a better view forward. The same design was used on the later A4 and V2 express engines. No. 2001 was fitted with a Crosby chime whistle which Gresley had obtained from Captain Howey of the Romney, Hythe and Dymchurch Railway, and which was originally intended for one of that railway's Canadian Pacific style locomotives. The second locomotive of the class, No.2002 Earl Marischal was completed by 1935, also at Doncaster, and was fitted with Walschaerts valve gear, as used on Gresley Pacifics, and had a greater superheater heating area of 776.5 sq ft (72.14 m2), obtained by using larger diameter fire tubes. At low cutoffs smoke clearance on No.2002 was unsatisfactory: wind tunnel experiments led to an additional second pair of smoke deflectors being fitted inward of the first. No. 2002 proved to be more efficient than 2001, due to a lower cylinder clearance volume and because the stepped-cam cutoff modifications made to No. 2001 reduced economical working relative to the infinitely variable cutoff of No. 2002. Consequently, the following locomotives were built with piston valves. By June 1936 the third engine had been produced: No. 2003, Lord President, based on the design of No. 2002 but with the external design modified to resemble the Silver Link locomotives. (see LNER Class A4). The locomotive weight was reduced to 107 long tons 3 cwt (240,000 lb or 108.9 t).[15] The wedge-shaped front was found to lift the engine's smoke clear of the driver's view;[15] No. 2002 was altered to this form in 1936, and No. 2001 in 1938. Three further locomotives, Mons Meg, Thane of Fife and Wolf of Badenoch, were under construction at Doncaster in 1936.