NER Class Z

NER Class Z LNER Class C7
Type and origin Power type Steam Designer Vincent Raven Builder North British Locomotive Co. Build date 1911-1918 Total produced 50
Specifications Configuration: ​  • Whyte 4-4-2 Gauge 1,435 mm (4 ft 8 1⁄2 in) Leading dia. 3 ft 7 1⁄4 in (1.099 m) Driver dia. 6 ft 10 in (2.083 m) Trailing dia. 4 ft (1.219 m) Tender wheels 3 ft 9 1⁄4 in (1.149 m) Wheelbase 53 ft 3 9⁄10 in (16.253 m)  • Engine 29 ft 6 in (8.992 m)  • Tender 12 ft 8 in (3.861 m) Axle load 20 4⁄5 t (20,800.000 kg) Loco weight 79 4⁄5 t (79,800.000 kg) Tender weight 46 3⁄5 t (46,600.000 kg) Total weight 125 3⁄10 t (125,300.000 kg) Fuel type Coal Firebox:  • Firegrate area 27 sq ft (2.5 m2) Boiler: ​  • Diameter 5 ft 6 in (1.676 m) Boiler pressure 175psi Heating surface:  • Tubes and flues Tubes: 763.9 sq.ft. (90x 2in) Flues: 534.5 sq.ft. (24x 5.25in)  • Firebox 185 sq.ft. Superheater: ​  • Heating area 392 sq.ft. (24x1.1in) Cylinders 3 Cylinder size 16.5×26in
Career Operators North Eastern Railway, London and North Eastern Railway, British Railways Class NER Z, LNER C7 Withdrawn 1943-1948 Disposition 2 rebuilt into C9s(see below), all scrapped

LNER Class C9
Type and origin Power type Steam Designer Nigel Gresley Rebuild date 1931 Number rebuilt 2
Specifications Configuration: ​  • Whyte 4-4-2 Gauge 1,435 mm (4 ft 8 1⁄2 in) Leading dia. 3 ft 7 1⁄4 in (1.099 m) Coupled dia. 6 ft 10 in (2.083 m) Trailing dia. 3 ft 8 in (1.118 m) Tender wheels 3 ft 8 in (1.118 m) Wheelbase 55 ft 7 in (16.942 m) Axle load 20 1⁄20 t (20,050.000 kg) Total weight 135 2⁄5 t (135,400.000 kg) Fuel type Coal Firebox:  • Firegrate area 2,317 3⁄5 sq ft (215.312 m2) Boiler: ​  • Diameter 5 ft 7 1⁄4 in (1.708 m) Boiler pressure 200psi Heating surface:  • Tubes 1178.4 sq.ft. (143x 2in)  • Flues 519.2 sq.ft. (24x 5.25in)  • Firebox 203 sq.ft. Superheater: ​  • Heating area 417 sq.ft. (24x1.2in) Cylinders 3 Cylinder size 16.5×26in.
Career Operators North Eastern Railway(before rebuild only), London and North Eastern Railway Class C9 Number in class 2 Numbers 727, 2171 Withdrawn 1942-1943 Disposition Both scrapped

The NER class Z (LNER Class C7) was an Atlantic class of locomotives designed by Vincent Raven. It was introduced in 1911.

Construction

Originally classified NER Class V2, the first 20 were built in 1911. Ten were saturated and the others were superheated. The saturated locos were superheated between 1914 and 1915, while all subsequent locomotives were superheated. 50 class Zs were built between 1911 and 1918, in 5 batches. Originally the locomotives were built with Schmidt superheaters, however from 1931 onwards 27 C7s were fitted with Robinson superheaters.

Variations

No.2212

The last of the 50 locos, No.2212 was built with Stumpf Uniflow cylinders. This arrangement had been used on LNER Class B15 No.825 with an untidy result, however the arrangement had been tidied up for No.2212. Double-length cylinders were required, thus a longer front bogie and smaller wheels were fitted. This arrangement, although requiring special attention (as with No.825) was used until 1934, when No.2212 was fitted with standard cylinders.

C9

In early 1931, Gresly rebuilt No.727 and 2171 (who were entering Darlington for repairs) with an articulated booster bogie, thus making them technically 4-4-4-4s. However the articulated bogie was considered split between the loco and tender in order to simplify classification. Originally the booster gearing was 1.5:1, however the trials of C1 No.4419 (also having boosters) showed that the booster help was practically nonexistent above 25 mph (40 km/h), meaning that the locomotives’ boosters were practically useless with the express, which would have to run with a speed of at least 30 mph (48 km/h). Hence, Darlington recommended that the booster gearing was to be changed to 1:1. This required larger cylinders to supply the same tractive effort, which required the boiler to operate at 200psi (25 psi higher than the C7s, which are 175psi) . Some have concerned about engaging the booster at higher speeds, however the unitary 1:1 gearing was considered to make this easier. The boilers were “Diagram 100” boilers (the ones used on the B17s), and followed Doncaster practises, rather than Darlington practises (which was used on the standard C7s). They also have Robinson superheaters, rather than Schmidt ones.

The growing amount of Gresley A1s, A3s and A4s marked the experiment redundant (seeing the A4s were scheduled to climb Cockburnspath hauling a 312 tons load at an average speed of 55 mph [89 km/h]).

Withdrawal

Withdrawal of the C7

Had World War 2 not intervened, withdrawal would have started before 1940. However withdrawal was pushed back to August 1943. Withdrawal was quick, however, with only 14 surviving to nationalization. Within a year, British Railways withdrew the remaining C7s, with none surviving into preservation.

Withdrawal of the C9

Their boilers were considered non-standard (compared to the C7s), thus they were withdrawn in April 1942(2171) and January 1943(727), before the first standard C7 was withdrawn. Neither of the two survived into preservation.

Loco details

List of NER Class Z locomotives

NER/LNER 1924 number	LNER 1946 number	BR number	Built date	Withdrawal date	Notes
706	(2950)	—	07/1911	12/1946
709	(2951)	—	07/1911	03/1946
710	(2952)	—	07/1911	02/1944
714	(2953)	—	07/1911	01/1944
716	2954	(62954)	07/1911	26/06/1948
717	(2955)	—	08/1911	04/1944
718	2956	—	08/1911	06/1946
719	(2957)	—	08/1911	04/1944
720	2958	—	08/1911	08/11/1947
721	(2959)	—	09/1911	02/1944
722	2960	—	08/1911	03/1947
727	—	—	09/1911	01/1943	Rebuilt as C9 in 11/1931
728	(2961)	—	09/1911	11/1945
729	(2962)	—	09/1911	11/1945
732	2963	—	10/1911	12/1946	Rebuilt with Lentz rotary cams-operated valve gear in December 1933
733	(2964)	—	10/1911	08/1945
734	(2965)	—	10/1911	09/1944
735	(2966)	—	10/1911	06/1945
736	(2967)	—	11/1911	04/1946
737	(2968)	—	12/1911	12/1945
2163	(2969)	—	05/1914	01/1946
2164	2970	(62970)	05/1914	27/12/1948	Last withdrawn C7
2165	2971	—	06/1914	02/1947
2166	2972	(62972)	06/1914	30/08/1948
2167	2973	(62973)	06/1914	26/06/1948
2168	2974	—	06/1914	05/1947
2169	2975	(62975)	06/1914	10/07/1948
2170	(2976)	—	06/1914	08/1943	First C7 withdrawn
2171	—	—	07/1914	04/1942	Rebuilt as C9 in 12/1931
2172	(2977)	—	08/1914	12/1944
2193	2978	(62978)	12/1914	30/08/1948
2194	(2979)	—	12/1914	09/1944
2195	2980	—	12/1914	06/1947
2196	2981	(62981)	02/1915	10/07/1948
2197	2982	(62982)	02/1915	24/07/1948
2198	2983	(62983)	03/1915	24/07/1948
2199	(2984)	—	03/1915	06/1944
2200	(2985)	—	03/1915	04/1946
2201	2986	—	04/1915	09/1947
2202	(2987)	—	05/1915	10/1943
2203	2988	(62988)	06/1915	24/07/1948
2204	2989	(62988)	06/1915	30/08/1948
2205	(2990)	—	11/1916	02/1945
2206	2991	—	11/1916	08/11/1947
2207	2992	(62992)	01/1917	01/11/1948
2208	2993	(62993)	02/1917	05/03/1948
2209	(2994)	—	04/1917	02/1944
2210	2995	(62995)	05/1917	10/07/1948
2211	2996	—	06/1917	08/11/1917
2212	(2997)	—	06/1918	10/1945	Fitted with Uniflow cylinders as built; rebuilt with standard cylinders and Lentz rotary cam-operated valve gear in 1934

Numbers in parentheses were allocated but not applied.

See also

• NER Class 4.6.2, which was based on the C7s
• NER Class R1, which the C7s were initially based on
• NER Class V and V/09, which the C7s were similar to

References

• Boddy, M. G.; Brown, W. A.; Fry, E. V.; Hennigan, W.; Hoole, Ken; Manners, F.; Neve, E.; Platt, E. N. T.; Russell, O.; Yeadon, W. B. (November 1979). Fry, E. V., ed. Locomotives of the L.N.E.R., Part 3A: Tender Engines—Classes C1 to C11. Kenilworth: RCTS. pp. 99–117, 122–129. ISBN 0-901115-45-2. Search this book on

Further reading

• Ahrons, E.L. (1987) [1927]. The British Steam Railway Locomotive 1825-1925. London: Bracken Books. p. 337. ISBN 1-85170-103-6. Search this book on
• Allen, Cecil J. (1974) [1964]. The North Eastern Railway. Shepperton: Ian Allan. pp. 200–1. ISBN 0-7110-0495-1. Search this book on
• Baxter, Bertram (1986). Baxter, David, ed. British Locomotive Catalogue 1825-1923, volume 5A: North Eastern Railway; Hull and Barnsley Railway. Ashbourne: Moorland Publishing. pp. 201–204. ISBN 0-903485-54-0. OCLC 503662482. OL 19991012M. Search this book on
• Brewer, F.W. (15 June 1925). "Atlantic type express engines, North-Eastern Section, L. & N.E. Ry". The Locomotive Magazine and Railway Carriage and Wagon Review. Vol. 31 no. 394. pp. 178–9.
• Gairns, J.F. (February 1915). The Railway Magazine. Vol. 36 no. 212.
• Grafton, Peter (2005). Sir Vincent Raven and the North Eastern Railway. The Oakwood Library of Railway History. Usk: Oakwood Press. pp. 73–75. ISBN 0-85361-640-X. OL137. Search this book on
• Hoole, Ken (1988). An illustrated history of NER locomotives. Sparkford: Oxford Publishing. pp. 175–9. Search this book on
• Hoole, Ken (1965). The North-Eastern Atlantics. Hatch End: Roundhouse. Search this book on
• MacLean, J.S. (c. 1923). The locomotives of the North Eastern Railway, 1841–1922. Newcastle: R. Robinson & Co. pp. 103–5. Search this book on
• Nock, O.S. (1974) [1954]. Locomotives of the North Eastern Railway. Shepperton: Ian Allan. pp. 136–9. ISBN 0-7110-0493-5. Search this book on
• Nock, O.S. (1983). British Locomotives of the 20th Century: Volume 1 1900-1930. London: Book Club Associates. pp. 91–93. CN5096. Search this book on
• "North-Eastern Three-cylinder Four-coupled Express Passenger Engine and Tender" (PDF). The Engineer. 112: 455. 3 November 1911.

External links

• LNER Class C7/NER Class Z
• LNER Class C9

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