NER Class Y

The North Eastern Railway (NER) Class Y (LNER Class A7) 4-6-2T tank locomotives were designed whilst Wilson Worsdell was Chief Mechanical Engineer, but none were built until 1910 by which time Vincent Raven had taken over.

NER Class Y
LNER Class A7
No. 9772 at Hull Dairycoates Locomotive Depot 1947
Type and origin
Power typeSteam
DesignerWilson Worsdell
BuilderDarlington Works
Build dateOctober 1910 – June 1911
Total produced20
Specifications
Configuration:
​
 • Whyte4-6-2T
 • UIC2′C1′ n3t, later 2′C1′ h3t
Gauge4 ft 8+1⁄2 in (1,435 mm)
Leading dia.3 ft 1+1⁄4 in (0.946 m)
Coupled dia.4 ft 7+1⁄4 in (1.403 m)
Trailing dia.3 ft 9+1⁄4 in (1.149 m)
Wheelbase34 ft 3 in (10.439 m)
Length43 ft 10 in (13.360 m)
Axle load19.50 long tons (19.81 t; 21.84 short tons)
Adhesive weight55.50 long tons (56.39 t; 62.16 short tons)
Loco weight87.50 long tons (88.90 t; 98.00 short tons)
Fuel typeCoal
Fuel capacity5.00 long tons (5.08 t; 5.60 short tons)
Water cap.2,300 imp gal (10,000 L; 2,800 US gal)
Boiler pressure160 to 180 lbf/in2 (1.1 to 1.2 MPa)
CylindersThree
Cylinder size16+1⁄2 in × 26 in (419 mm × 660 mm)
Valve gearStephenson
Valve type7+1⁄2-inch (191 mm) piston valves
Performance figures
Tractive effort26,140 to 29,405 lbf (116.28 to 130.80 kN)
Career
Operators
Power classBR: 5F, 3F from May 1953
Axle load classLNER/BR: Route availability: 7
Withdrawn1951 - 1957
DispositionAll scrapped

Overview

The Class Y locomotives were intended for hauling coal trains and were developed from the NER Class X (LNER Class T1) 4-8-0T heavy shunters. However, they had larger boilers and smaller cylinders for higher working speeds. Twenty were built in one batch and numbered between 1113 and 1195. Originally built with saturated boilers pressed to 175 lbf/in2 (1.21 MPa), seven locomotives were later fitted with boilers equipped with superheaters and pressed to 160 lbf/in2 (1.10 MPa).[1]

All twenty locomotives passed to the London and North Eastern Railway at the 1923 Grouping. The LNER left the NER's locomotive numbers unchanged, but raised the boiler pressure of the saturated locomotives to 180 lbf/in2 (1.2 MPa). They also fitted ten more locomotives with the 160 lbf/in2 superheated boilers that the LNER classified as diagram 55.

By the time the A7s entered LNER ownership in 1923, the A7s had been relegated to shunting in the larger marshalling yards. Their power was invaluable when shunting heavy trains over the shunting hump. In the 1930s, Nos. 1136 and 1175 were allocated to hauling chalk quarry trains from Hessle Quarry to Stoneferry Cement Works, in the Hull area.

Heavy mineral traffic declined after the end of World War II, and the A7s moved to the Hull area, except for Nos. 1181 and 1192 which stayed at Stockton. At Hull, the A7s replaced the old Hull and Barnsley Railway (H&BR) types which were being withdrawn at that time.

During LNER ownership in the 1940s, two locomotives were rebuilt with diagram 63B superheated boilers pressed to 175 lbf/in2; the locomotives were then assigned to Class A7/1.

In the LNER 1946 renumbering scheme, the class received the 9770 to 9789 block; at nationalisation in 1948 all 20 locomotives passed to British Railways they were assigned the numbers 69770–69789, although the last locomotive was withdrawn before it was renumbered.

BR continued the rebuilding scheme, dealing with another 13 locomotives, although one received a diagram 63B saturated boiler and one a diagram 63C superheated one. Both were pressed to 175 lbf/in2.

Withdrawal

The A7s were withdrawn between 1951 and 1957 and none have survived into preservation.

Fleet list
Table of locomotives[2]
NER No.LNER 1942 No.Date builtDate superheatedDate rebuiltDate WithdrawnNotes
11139770Oct 1910May 1922Jul 1950Oct 1954
11149771Nov 1910Sep 1924Jun 1948Nov 1954
11269772Nov 1910Jul 1917—Dec 1957
11299773Dec 1910Oct 1930Jul 1951Mar 1955
11369774Dec 1910May 1932May 1950Aug 1954
11709775Dec 1910—Nov 1945Apr 1952
11749776Jan 1911Jan 1930Jan 1952Jun 1954
11759777Jan 1911May 1919—May 1952
11769778Feb 1911——May 1955
11799779Feb 1911Feb 1929Dec 1949Nov 1954
11809780Feb 1911Dec 1930Jan 1950Nov 1954
11819781Mar 1911Mar 1929Apr 1951Nov 1956
11829782Mar 1911Mar 1923—Dec 1957
11839783Mar 1911Nov 1928Apr 1948Dec 1956
11859784Apr 1911Mar 1922May 1948Mar 1956
11909785Apr 1911Nov 1918Sep 1943Nov 1955
11919786May 1911Apr 1930Apr 1948Dec 1957Rebuilt with superheated dia 63C boiler
11929787May 1911—Aug 1951Aug 1954Rebuilt with saturated dia 63B boiler
11939788May 1911Sep 1920Jul 1948Nov 1955
11959789Jun 1911Nov 1922—May 1951Withdrawn before BR number applied

References
  1. Fry 1964, p. 17.
  2. Fry 1964, p. 19.
  • Fry, E. V., ed. (April 1964). Locomotives of the L.N.E.R., part 7: Tank Engines - Classes A5 to H2. Kenilworth: RCTS. ISBN 0-901115-13-4.
  • Ian Allan ABC of British Railways Locomotives, part 4 (1948 ed.). p. 55.
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