274 13/5/1913 456-60 O1, O3
283 8/2/1916 461 O2
N.B. Loco. Co.  2/1918 462-71 O1, O3
N.B. Loco. Co. 2/1918 472-76 O1,O3
N.B. Loco. Co. 18/3/1919 477-86 O2/1
298 26/2/1923 3487-96 O2/2
326 12/1929 2954-61 O2/3
328 2/1932 2430-37 O2/3
359 6/1940 3833-42 O2/3
364 6/1941 3843-52 O2/3
365 6/1941 3853-57 O2/3


 No. 456 CLASS

4ft-8in wheels, cyls 21in x 28in, 10in piston valves, Gresley Dgm 13 boiler, LNER Dgm 2 boiler

BO 616 issued (24/2/1913) for five boilers for Nos. 456-59,
BO 616 amended to six boilers (17/3/1913) to provide one spare for EO 274,
BO 616 originally ordered with 165 x 2in boiler tubes, later amended to 167 x 2in,

Cylinders dwg M171 (4/1913),
Frame dwg O106 (4/1913) was for Nos. 456-60,
Pony truck dwg O107 (5/1913) for EO274,

Firebox dwg N251 (5/1913) for BO 616,
Boiler dwg N256 (-) for BO 616,
EO 274 issued (13/5/1913) for Nos. 456-60,
General Plan dwg P54 (28/5/1914) for 456-60,

Frame plate dwg O121 (17/4/1918) for 462-76,
Frame dwg O122 (5/5/118) for 462-76,
General Plan dwg P57 (8/1918) for 462-76,
General Plan dwg P60 (10/1921) for 462-76.

Nos. 456-60 were built at Doncaster (1913-14), Nos. 462-71 were built by North British Locomotive Co. (1919) (using American material) and Nos. 467-76 were built by North British Locomotive Co. (1919) (using British material).

Gresley conducted several feed-water experiments with these engines.  Nos. 456-60 when new had a Weir pump and water heater, located between the frames.  In October 1916 No. 459 was modified.  The heater was dispensed with.  Cold water was now pumped into the top of the boiler on to collection trays inside an additional dome casing located behind the ordinary dome.  A single elongated cover was fitted over both domes.  The Weir feed pumps were later removed from Nos. 456-60.  No. 476 was fitted in November 1922 with a Worthington feed water heater and boiler feed pump mounted on the left hand side of the engine to make it more accessible. 

Class O1 became Class O3 (February 1944) so that O1 could be used for Thompson's rebuilds from Class O4.  The engines were renumbered 3475-94 (1946).  Nos. 3487/90/92 were withdrawn in 1947, leaving seventeen to enter into BR ownership.  Nos. 3489/94 were withdrawn in 1948 and the survivors had 60000 added to their numbers (1948-50).  The remainder were withdrawn in 1951-52. 


No. 461 CLASS

4ft-8in wheels, cyls (3) 18in x 26in, Gresley Dgm 13 boiler, LNER Dgm 2 boiler

Frames were ordered 23/2/1916,
Cylinders dwg M212 issued (3/1916),
Pony truck dwg O117 (3/1916) for No. 461,

EO 283 was issued (8/12/1916) for No. 461,
Frame dwg O119 (12/7/1917) for No. 461,

Remainder of material ordered from 2/1917 onwards,
The spare boiler provided for Nos. 456-60 (see above) was taken for No. 461

No. 461 was built at Doncaster 1918.

Its cylinders were inclined with their exhaust steam pipes out of sight.  This was Gresley's first application of his 2-to-1 conjugated valve gear.  This was the first Doncaster-built engine with vertical screw reversing gear.  No. 461 was renumbered 3461 (1925).  It was given a side-window cab (3/1940) to clear the 13ft gauge of the proposed electrification scheme.  It was renumbered 3921 (1946) and withdrawn in May 1948.


4ft-8in wheels, cyls 18in x 26in, Gresley Dgm 13 boiler, LNER Dgm 2 boiler

EO 288 was issued (18/3/1919) for Nos. 477-86,
Cylinders dwg M261 issued (12/1919),
Nos. 477-86 were ordered (4/1920) from North British Locomotive Co., without tenders, with the bulk of the material supplied by the GNR.

Nos. 477-86 were delivered in May 1921.

These engines were originally intended to have Ramsbottom safety valves.  After Class H4 No. 1000 appeared (3/1920) the O2 order was amended (26/4/1920) for them to have 2in Ross "pops", later amended to 3in, "to blow off at 180 & 182 lb as on 1000 eng."  (The front valve blew off at 180lb and the hind valve at 182lb.)

BO 660 was issued (16/5/1922) for five spare boilers.  Instead they were taken for Nos. 487-91.


LNER Class O1 was intact at Grouping : 20 in service
LNER Class O2 was intact at Grouping : 11 in service, added to by new construction

BO 663 issued 27/1/1923 was the first BO issued after Grouping, for Nos. 487-96.  Instead they were taken for Nos. 492N-3501,
BO 664 was issued (26/2/1923) for (GNR) Nos. 497-501.  Instead they were used as spares during 1924,
EO 299 was issued (2/1923) for (GNR) Nos. 487-501,
EO 300 was issued (26/2/1923) for (GNR) Nos. 497-501.

Nos. 3487-91, 492N-95N, 3498-3501 were built at Doncaster (1923-24).

These engines had a lower cab profile to clear the Composite Load Gauge (13ft-1in).

These engines were renumbered 3477-86 (1924-26).  In January 1925 No. 3500 was fitted with a Dabeg feed water heater and pump, located on the left-side running plate.  In August 1931 No. 3499 acquired two such feed water heaters, in this case incorporated in an elongated dome casing on the boiler top in the boiler previously fitted to class to No. 3459 (see earlier).  The apparatus was removed in October 1937.  In February 1929 No. 3461 acquired this double domed boiler and in December 1931 it acquired a similar feed water arrangement to No. 3499 except that the top feed was inside the extra dome.  This experiment ended in November 1935 when the boiler was condemned; No. 3461 was reboilered and reverted to normal.

Nos. 3477-86 were given side-window cabs (1939-40) to clear the 13ft gauge of the proposed electrification scheme.  There was no need to alter Nos. 3487 onwards as they already cleared this gauge.

No. 3480 (latterly 63925) was given a Thompson Dgm 100A boiler (10/1943).  No. 3487 (latterly 63932) was given a similar boiler and fitted with a side-window cab (10/1944).  These rebuilds were classified Class O2/4 (1947).

The engines were renumbered 3922-46 (1946) and 63922-46 (1948-50).

A further ten O2s, Nos. 63925/26/28-31/33/35/38/45, were fitted with Dgm 100A boilers (1956-62); also side-window cabs where not already fitted.  However for a short time No. 63932 (which had been altered in 1944) temporarily reverted to a Dgm 2 boiler (6/1949-1/1958) though of course the side-window cab was retained throughout.

For details of LNER-built O2s refer to LOCOMOTIVES OF THE L.N.E.R. (RCTS) Part 6B.

Preamble,  Plant Works,  A 4-2-2,  A 4-6-2B 2-2-2C 4-4-2C 4-4-2TD 4-4-0E 2-4-0F 0-4-2,
F 0-4-2T,  G 0-4-4TH 2-6-0
J 0-6-0 J 0-6-0ST,  J 0-6-0T,  K 0-8-0,  L 0-8-2T,  MC Motor coach,
N 0-6-2T