Position at Grouping and its immediate effect

On 1st January 1923 Gresley was appointed CME and so replaced John Robinson at Gorton, Vincent Raven at Darlington, Arthur Hill at Stratford, Walter Chalmers at Cowlairs and Thomas Heywood at Inverurie.  He only just missed succeeding Patrick Stirling’s son Matthew at Hull, as the Hull & Barnsley had been absorbed by the NER in 1922.  Their Works retained a certain amount of autonomy, mainly as far as their own designs were concerned although later Darlington was responsible for new 0-6-0s, 4-4-0s, No. 10000 and Group Standard tenders.  Certain pre-Grouping classes which had been ordered before 1923 were not cancelled, whilst later, others, not just ex-GNR types were considered the correct solution for local problems.  For instance GER N7 with some Gresley modifications, or the NER J72 as originally built in 1898.  Those engines which appeared shortly after Grouping were as follows:

Cowlairs: Class N15 Nos. 9019 etc.
Darlington: Class B16 Nos. 1371-85, 2366-82; J27 Nos. 2383-92;
Class T1 Nos. 1656-60; Class Y7 Nos. 982-86
Doncaster Class A1 Nos. 4472-81; Class J50 Nos. 3231-40
Gorton: Class B7 Nos. 5475-84.

The LNER also purchased 273 ROD 2-8-0s (1923-29) which were added to stock as Class O4.

Certain existing classes were added to after Grouping, in some cases for use on other Sections, as follows:
Class A1 Nos. 2543-82
Class D11 Nos. 6378-6401
Class D16 Nos. 8780-89
Class J50 Nos. 583 etc.
Class J72 Nos. 500 etc., also 69001-28 built after Nationalisation
Class K3 Nos. 17 etc.
Class N2 Nos. 892-97, 2583-94, 2662-90
Class N7 Nos. 409 etc, 907 etc., 2699-61
Class S1 Nos. 2798/99 in connection with booster application.


No change was needed for the (straight) frames for engines with narrow fireboxes, but the Pacific frames (both A1 and A3) gave problems, with small cracks frequently appearing.  The problem eventually eased when the lightening holes in the frame plates were discarded (from October 1933) except for those ahead of the cylinders.  In the meantime most of original frames had received new “half-frames” or “three-quarter frames” where the cracks had been too severe to repair by welding.  Otherwise, the same frame design was used for the A1s, P1s and A3s.

The frames for Class W1 No. 10000 were probably designed at Darlington, to Gresley’s broad outlines especially at the rear end.  The main frames were 47ft.-2½in. long overall and the chief difference with their A3 counterpart was at the rear end where they were set in 3ft.-1¼in. apart instead of 3ft.-5in.  In addition, the outside frames were joggled outwards beyond the Cartazzi truck and were 6ft.-10in. apart alongside the Bissell truck.  The Cartazzi slides were arranged at a slope of 1 in 10.66 from the horizontal, with an initial restoring force of 1 ton rising to 1.2 tons with 2½in. sideways movement.  The Bissell truck had side control springs, with an initial load of 0.75 tons rising to 1.8 tons at full sideways displacement.  The original frames were retained when the engine was rebuilt in 1937.

The P2 frames were 45ft.-5¼in long overall, formed from three sections. These were the main frames 36ft.-9½in. long alongside the coupled wheels and under the cab, spaced 3ft.-11¼in. apart (to give extra clearance for the lengthy coupled wheelbase).  Under the cab they were set in to 3ft.-5in. as in the later A3s.  The front-end frames were 13ft.-1¼in. long and the normal 4ft.-1½in. apart.  Both the front-end and main frames were 11/8in. thick and their 4ft.-4½in. overlap gave extra strength around the leading driving horn guides.  The rear-end outside frames (now supporting a longer firebox than in the A1s and A3s) were 11ft.-3¼in. long, 1in. thick, and 6ft.-0½in. apart at the rear.

The frames for Class A4 were similar to those of Class A3, except at the rear end, where the parallel section under the cab was set in 3ft.-2½in. apart instead of 3ft.-5in.  The V2s had similar frames at the rear end.

The final Gresley class with a wide firebox was the V4.  The frame arrangement at the rear similar to that of V2, with the parallel section under the cab set in 3ft.-2½in. apart.  However the outside frames were 5ft.-10in. apart instead of 6ft.-0½in.


Boiler design was shared between the various Works, so that modifications affecting pre-Grouping classes would be dealt with by the appropriate Drawing Office.  New designs would be concentrated at Doncaster, with the other centres called upon to assist is necessary.  Boiler diagrams numbered in the upper end of the series used from July 1928 were as follows including for completeness those issued by Gresley’s successors.

Post-Grouping Boiler Classes


LNER Classes

25A B12, J20


A1, A2 (2404), P1
A1 (A10), P1
A3, P1




K5, certain K3


D49, J38/2, J39




B12/2 (later became Dia 25)


B1, B2, B3/3, B17/6, O1, O2/4, O4/8






W1 (new)




S1/2 (1 engine), S1/3, O4 (1 engine)


P2/1, P2/3
A2/2 (5 engines)


A1/1, A4, A3


A2/2 (1 engine)


A2/1, V2




W1 (rebuilt)




V4 (with thermic syphon)






K1, K1/1


A2/3, A1, A2, A2/2


A1, A2, A2/2, A2/3





DIAGRAM 94.  Twenty boilers were ordered (12th October 1923) for new engines Nos. 2543-62.  The order was amended (23rd December 1924) for two of these boilers to have “E” type superheaters instead of the Robinson type.  Eighteen of the boilers were taken by Nos. 2545-62, the other two by Class P1 Nos. 2393/94.  Boilers with “E” type superheaters were fitted to Nos. 2562 and 2394.  The two boilers ordered (28th December 1923) for the P1s then became spares (not needed until 1926).  N. B. Loco. Co. built Nos. 2563-82.  No further Diagram 94 boilers were constructed, so there were just two spares for both A1 and P1 classes.  Rebuilding to Class A3 (with Diagram 94HP boilers) commenced in 1927, releasing further Diagram 94 boilers, one of which was fitted to Class A2/2 No. 2404 (June 1929).  This was the only Raven Pacific fitted and it was withdrawn in February 1937, its boiler then becoming just another spare A1 boiler.  The last Diagram 94 boiler was taken out of service in November 1948 when Class A10 No. 68 entered Works for rebuilding.

DIAGRAM 94HP.  The first five boilers were ordered 11th March 1927 for five A1 to A3 conversions, two for fitting at Doncaster to right-hand drive engines (late 1927), and three for fitting at Darlington to left-hand drive engines (early 1928).  Ten further boilers were ordered (3rd August 1927) for new A3s 2743-52.  Four more boilers were ordered 25th February 1928 as spares.  Eight boilers were ordered (18th December 1928) for new engines Nos. 2595-97, 2795-97, 2598/99, but construction delays meant that four of those engines (Nos. 2595-97, 2795) instead took boilers from the February 1928 “spares” order.  This left four “spares” in the December 1928 order, which were used for existing A3s in 1930-31.  Two more spare boilers were ordered 22nd February 1933 but not used until 1935.  No further Diagram 94HP boilers were constructed.

DIAGRAM 94A.  The first of these boilers, i.e. with perforated steam collectors, were ordered 4th November 1933 for new engines, Nos. 2500-08.  Ten spare Diagram 94 boilers were ordered (17th January 1938) for Class A1, but this was corrected eight days later to read 94A boilers. These were fitted in 1939-41, some to existing A3s, and others used for conversions.  From then onwards new boilers were shared between existing A3s and those needed for conversion.  Further Diagram 94A orders were made 13th April 1939 (10 boilers, fitted 1941-43), 2nd November 1942 (10 boilers, fitted 1943-44), 12th March 1943 (5 boilers, fitted 1945-46), 11th May 1943 (7 boilers, fitted 1946).

Ten further Diagram 94A boilers were ordered (10th May 1944), but the last nine were turned out as 94HP, i.e. no perforated steam collector, in line with Thompson’s present thinking, though by the time they had been completed Thompson had retired.  The solitary 94A boiler was fitted in December 1946, the nine 94HPs between January and June 1947.  Ten more Diagram 94A boilers were ordered (26th March 1947) and fitted in 1949.  The final Diagram 94A order for ten boilers (19th August 1947) was completed in 1950.  A start was made in 1954 fitting A3s with Diagram 107 (A4 type) boilers.

DIAGRAM 95.  This was the Beyer Peacock boiler for the Class U1 Beyer-Garratt 2-8-8-2 No. 2395.

DIAGRAM 96.  This was the GN-designed boiler for Class K3, mentioned already.

DIAGRAM 97A.  This boiler was designed at Darlington for new class J38 0-6-0 mineral engines for operating in Scotland only.

DIAGRAM 97.  This was designed at Darlington for Class J39, which had larger wheels than Class J38.  Thus the boiler was based on Diagram 97A, but with a 2½in shallower firebox to clear the larger wheels. These boilers could be fitted to a J38 but not vice-versa.  The J39 was a universal 0-6-0 type intended to supersede almost all pre-Grouping 0-6-0s.  They could be seen operating just about anywhere, except for the GNS section which had never any indigenous 0-6-0s anyway.  They did operate from Aberdeen (Ferryhill) so could have visited Kittybrewster shed for repairs, and even Inverurie Works.  The boiler was also fitted to Class D49 4-4-0 passenger engines, basically intended to replace pre-Grouping 4-4-0 classes in Scotland and the NE Area.  From a design point of view D49 and J39 boilers were not strictly interchangeable.  During construction their expansion brackets were attached to the firebox sides at different heights (almost 1ft difference). There were a handful of examples of boilers migrating between these classes, which meant first of all replacing their expansion brackets.

DIAGRAM 98.  This was designed at Doncaster (drawing N493, September 1926) for new Class N7/3 0-6-2T Nos. 2600-31 built at Doncaster, to supplement the existing members of the class operating on the GE Section.  The boiler had a round-topped firebox in accordance with Gresley practice, whereas the earlier N7s all had Belpaire fireboxes.

DIAGRAM 101.  This was a revised version of Diagram 98, with an altered tube arrangement, and possibly a shallower firebox.  This may have been designed at Stratford.

DIAGRAM 99.  These were ten boilers built by Beyer Peacock for Class B12/2 Nos. 8571-80.  This diagram was incorporated with Diagram 25 (1938), from which they differed little.

DIAGRAM 99A.  This was a 5ft.-6in. diam. boiler designed (by Thompson) at Stratford to replace the existing smaller diameter boilers on the B12s.  These engines were Class B12/3.  Far more B12s were rebuilt with these boilers than with the smaller Diagram 25A mentioned next.

DIAGRAM 25A.  This round-topped boiler (5ft.-11/8in. diam) was drawn out at Doncaster (N1033, February 1940) for fitting to Classes B12 and J20, to supersede the Belpaire-type Diagram 25.  The first fifteen boilers ordered (BO890, issued 29th July 1941), numbered 9410-24, were constructed at Doncaster (1942-44).  Boilers 9410/11/19/24 went to Cowlairs for fitting to B12s (1943-45), becoming Class B12/4, and the remainder went to Stratford for fitting to J20s (1943-45), becoming Class J20/1. A further batch of 15 boilers was ordered in September 1944 from Doncaster. Five boilers (numbered 4465-69) went to Inverurie for B12s, five (numbered 4470-74) went to Stratford for J20s.  Construction of the final five (numbered 4475-79) was diverted to Stratford Works, where they were built and fitted to J20s.

DIAGRAM 100.  The boiler for Gresley’s Class B17 4-6-0s had fireboxes 10ft.-1½in. long, including a combustion chamber, so the length measured at the base was 9ft.-0in, which made it 6in. shorter than the Diagram 2 firebox on Class O2.  There is no evidence that Doncaster was involved in its design and it was presumably dealt with by North British Locomotive Company, to Gresley specification.  There was a scheme to fit the fireboxes with thermic syphons (N1003, September 1939), but this was cancelled a month later.  The Diagram 100 boiler was adapted by Thompson as his standard Diagram 100A boiler.

DIAGRAM 102.  This boiler was design for Gresley’s Class V1 2-6-2T, introduced in 1930. 

DIAGRAM 102HP.  This version differed from Diagram 102 in having the boiler pressure raised from 180 to 200 lb/sq in.  The majority of V1s were rebuilt to Class V3.

DIAGRAM 103.  This was the water-tube boiler built by Yarrow for Class W1 No. 10000.

DIAGRAM 104.  This was the round-topped boiler fitted to Class C9 Raven Atlantics Nos. 727 and 2171 rebuilt with boosters, and was presumably designed at Darlington to Gresley specifications.  The tube arrangement was similar to that of Diagram 100.

DIAGRAM 105.  This was the round-topped boiler fitted to Class S1 Nos. 2798/99, built at Gorton with boosters 1932.

DIAGRAM 106.  These were the boilers originally intended for Gresley’s Class P2 2-8-2s. The differed from the A3 boiler in one major respect. The firebox was larger providing a grate area of 50 sq. ft.  Two boilers were ordered (1st March 1933), reduced to one only (1st April 1933). This was fitted to No. 2001.   A second boiler was ordered (4th November 1933) for No. 2002.  The final four boilers were ordered (same date) for Nos. 2003-06).  However, only three of these were fitted in 1936, to Nos. 2003/04/05, as in the meantime a Diagram 108 had been ordered for No. 2006 (see later).  The spare boiler was at last fitted (as a replacement) to No. 2002 (April 1940).  All six boilers were subsequently rebuilt by Thompson to Diagram 106A.

DIAGRAM 107.   This was perhaps Gresley’s most successful boiler, fitted to Class A4.  The boiler had a large firebox like that of the P2 boiler, but with increased working pressure raised to 250 lb./sq. in.  An A4 boiler was used in Thompson rebuilding of Class A1 No. 4470, and they were used from 1954 as general replacements for Class A3.

DIAGRAM 108.  This was a Diagram 106 boiler with 1ft shorter barrel and 1ft longer firebox casing and combustion chamber.  It was fitted when new to No. 2006, and was subsequently rebuilt by Thompson to Diagram 108A.

DIAGRAM 109.  This was the boiler fitted to the Gresley Class V2 2-6-2s, and was an A3 boiler with a 2ft shorter barrel.  Thompson retained this boiler for his four Class A2/1 4-6-2s that had been ordered as V2s. The only change was the increase in working pressure from 220 to 225 lb./sq. in, without any strengthening of boiler plates being needed.

DIAGRAM 109 MODIFICATION.  Gresley intended fitting V2s with boilers working at 250lb./sq. in. (drawing N1058, March 1941).  The fireboxes would have been made of steel plate and fitted with Nicholson Thermic Syphons.  This scheme was cancelled and interestingly the next boiler drawing number, N1059 (dated March 1942), was for Thompson’s B1 boiler, which suggests a deliberate lengthy delay in completion by unenthusiastic LDO staff after Thompson had issued his instructions. 

DIAGRAM 110.  This was the boiler (N860, September 1936) for the Gresley Class K4 2-6-0s.  The length of barrel was 11ft.-9in., and the length of the firebox at the foundation ring was 8ft.-11in. 

DIAGRAM 111.  This was the boiler fitted to Class W1 No. 10000 when rebuilt in 1937.  It was based on the Diagram 107 boiler but with a larger firebox (N878, January 1936).  There was no spare boiler, though consideration was given in later years to it being given a Diagram 118 boiler.

DIAGRAM 112.  This was the boiler fitted to Class V4 No. 3401.  The diameter of the barrel was 5ft.4in. at the firebox end, tapering to 4ft.–93/16in. just ahead of the dome.  The firebox was the wide type, like the V2s, but on a smaller scale.

DIAGRAM 113.  This boiler was fitted to Class V4 No. 3402 and was similar to Diagram 112, except that the firebox incorporated a thermic syphon.  This was removed in March 1945, so effectively the boiler became Diagram 112.

Safety valves

Shortly after Grouping, many D1s and N2s finished up in Scotland where it was usual to remove their Ramsbottom safety valves and substitute Ross “pop” valves on special brass seating blocks.  Several C1s were similarly altered after Grouping.  However the general application of Ross valves on new boilers for GNR classes (surprisingly including new engines in Classes J50 and N2) was not until 1926. The last boilers built at Doncaster and drilled to take Ramsbottom valves were four Diagram 8 boilers for the M & GN. These were despatched in July 1926 without tubes or mountings.


The “E” type superheater had 45 x 2¼in. diam. small tubes and 124 x 3½in. diam. flue tubes. The flue tubes were traversed by 29 “2-element” units, each traversing four adjacent flue tubes, and 4 “single-element” units, each traversing two flue tubes.  The “2-element” units branched into two elements near to the front tube plate one above the other.  The two branches united prior to entering the superheater header.  Each branch thus traversed two adjacent flue tubes once, as against the standard arrangement of each element traversing the same flue tube twice.  No. 2562 received one of these superheaters so it could be compared in trials against another Pacific with an ordinary boiler.  The results from the trials convinced Gresley there was no advantage in adopting the “E” type superheater.  No. 2562 was reboilered in August 1930, and its displaced boiler was given a conventional superheater.  The P1, No. 2394, received a standard 32-element superheater in November 1931, without a boiler change.

The “E” type having proved unsuccessful Gresley asked Doncaster (8 January 1927) to consider increasing the number of flues in the conventional Robinson superheater.  It was decided to use a similar arrangement to that of the German State Railways 4-6-2s which had 43-element superheaters.  There was insufficient clearance in the Gresley Pacific smokebox for the wider header and this was solved by fitting cover plates over the holes need for the headers.  The arrangement of the header was one row of 10 elements below which were three rows of 11 elements.

The Beyer-Garratt Class U1 2-8-8-2 No. 2395 (new August 1925) had a 45-element Robinson superheater.  Two anti-vacuum valves were fitted behind the chimney.

The multiple valve regulator with superheater header fitted to Class D49 No. 335 (new August 1928) would probably have had ball-joint (BJ) connections for their elements instead of the traditional Robinson type.  This could have passed unnoticed in Doncaster LDO as the engine was maintained at Darlington.  Darlington also built five V2s Nos. 4804-08 (1938) with a similar arrangement, for which Doncaster LDO had prepared the drawings (N893, May 1937).  The method of attachment of elements to header was the Through-bolt.

From January 1941 replacement headers for A3s (which basically involved the remaining A1s when rebuilt to A3) were the BJ-type.

Steam Collection

Class D49 4-4-0 No. 335 (new August 1928) had a multiple valve regulator and superheater header. As with the Swindon arrangement the regulator valve was in the smokebox on the output side of the header, with the same advantages.  Five Class V2 2-6-2s Nos. 4804-08 (new 1938) received a similar arrangement.  The equipment was eventually removed from these five engines by Thompson during 1942-44.  In BR days multiple valve regulators and superheater headers was fitted to Peppercorn Class A2 Nos. 60526/29/32/33/38 (fitted 1949), and they became a feature of the BR Standard engines Doncaster subsequently built.

The boiler for Class P2 2-8-2 No. 2001 (new May 1934) Gresley had a perforated steam-collector inside the dome. This was fed by a series of ½in. slots, eighteen in number, in the top of the barrel plate.  Steam collectors were afterwards fitted to all new boilers for his big engines, Classes A3, A4, P2, V2 and W1, but not fitted to existing boilers.  They were even fitted to the smaller Class V4 2-6-2s, though they only needed eleven slots.  It was later thought that furring up of the slots would in time become a limiting factor for steam flow at high speed, and from May 1941 the slots were replaced by eighteen rows of 5/8in diam. holes.

Conjugated Valve Gear

The arrangement on the LNER classes posed little trouble, except for the Darlington-built Class D49 Shire 4-4-0s.  As the cylinders were in the same plane it was possible to arrange the 2 to 1 levers behind the cylinders, away from smokebox ash which could no longer affect the pin joints.

Seven B16’s were rebuilt in 1937-40 (Nos. 846, 926, 1372/74, 2364/66/67), including the removal of the inside valve gear and replacing it with the 2 to 1 gear arrangement.  Design work appears to have been carried out at Darlington, where the engines were rebuilt.  As was to be expected, later rebuilds under Thompson retained their third set of Walschaerts valve gear.

This was one feature that Thompson was at pains to get rid of, in particular by rebuilding No. 4470 “Great Northern” and the six P2s.  But it was relatively trouble-free, and would have been a costly exercise to alter the Gresley engines with this gear.


Gresley bogies continued to have swing link side-control (until the merits of the D49 bogie dictated that the helical spring side-control was to be preferred) and the usual helical load bearing springs.  His standard bogie wheelbase was 6ft.-3in., with the exception of Classes D49 and W1, whose bogies were designed at Darlington.  The Doncaster bogie was pivoted 1½in behind its centre line, normal practice since 1870, but this was altered later.

The D49-type bogie first appeared in 1927 and was designed at Darlington.  The wheelbase was 6f.-6in., wheel diameter 3ft.-1¼in., axle journals were 10in. long (11in. from 1932) by 6½in. diam, sideway movement was controlled by helical springs and the weight was supported by laminated bearing springs.  The D49 bogie was not fitted to any other class and the term “D49 bogie” chiefly referred to the method of sideways control.

Gresley’s next design was the B17, though Doncaster had little to do with it. It had D49-type side control springs, but the wheelbase and wheel diameter were the Doncaster standard.  D49-type laminated bearing springs may have been fitted at first, but this has not been confirmed.

The solitary W1 appeared in 1929.  Its bogie too had been designed at Darlington and its frames were constructed of 11/8in. thick steel plate spaced 4ft.-0in. apart.  It had the D49-type features of 6ft.-6in. wheelbase, wheels pivoted at their central point, generous axle journals 11in. long (at that time only 10in in Class D49) by 6½in. diam., helical spring side control, and laminated bearing springs.  The wheel diameter though was the Doncaster standard, 3f.-2in.

From April 1931 the swing-link bogies were converted to spring-side control.  The first drawing O193 (April 1931) showed the wheelbase as 3ft.-3in. + 3ft.-0in. and this arrangement was fitted to No. 4478 (April 1931). This was followed by O194 (August 1931) with the wheelbase 3ft.-1½in. + 3ft.-1½in. and this arrangement was fitted to No. 2747 (October 1931).  Both had the usual helical bearing springs.  After trials were completed (August 1932) the majority of Pacifics received O194 bogies in 1933-34. 

The A4 bogies were the same as those fitted to the A3s, with the now standard spring side control.  The sideways movement was greater, presumably because of the extra weight being supported. Stiffer helical bearing springs and longer axle journals (11in. instead of 9in.) were tried out on No. 4498 (January 1939) but made no improvement.  Various other experiments were tried out, but were curtailed at the outbreak of War in September 1939, other than the extended fitting of stiffer springs and longer axle journals.

The W1 was rebuilt in 1938 and its original non-standard bogie received helical bearing springs.  It is understood that the original fames had to be replaced at its March 1939 repair because of cracking.

Several Gresley classes appeared after Grouping, P1, P2, V1 (V3), V2, K4 and V4, all with double swing link pony trucks, 3ft.-2in. diam. wheels, and helical bearing springs.  Only the length of radius of the bar arm was different, as shown below:
Class P1 (1925), 6ft.-6in.
Classes V1 (1930) and V3 (1939), 5ft.-11½in.
Class P2 (1934), 6ft.-9½in.
Class V2 (1936), 6ft.-63/8in.
Class K4 (1937), 6ft.-7in.
Class V4 (1941), 6ft.-1in.

No details are available for Class U1 2-8-8-2T other than it had 2ft.-8in. wheels like Class O2 (production).

P2 Crank Axle Failures

There were three recorded examples of crank axles failing in traffic, as follows.

18/7/1939. No. 2005 broke its axle which was 2y-11m old.
27/5/1942.  No. 2004 broke its crank axle starting out of Kirkcaldy with the 2.0 p.m. Edinburgh – Aberdeen express, with driver L. Daniel.
29/7/1944. No. 2003 broke its crank axle 2 miles south of Aberdeen working the 8.50 Aberdeen – Edinburgh express. The axle mileage was 243,267.

Thompson could be excused for rebuilding these engines, though they didn’t have a good reputation afterwards either. No. 2005 for example had eight light repairs at Cowlairs Works during 1945, at the end of which it was reported “Trouble mainly due to (1) cylinders working loose, (2) exhaust pipe failure, (3) steam pipes torn away from header.  Alterations have been made to overcome the difficulties.”  Whether these were design errors or the result of war-time maintenance is not known.


Post Grouping, the first four Doncaster Tender Orders were a continuation of GNR practice.
TO42/43 (9/4/1923) Ivatt Class B 3500 gallon tenders,
T.5233-42, T5243-52. Fifteen of these were intended for new Class O2 Nos. 3487-3501.
TO44/45 (29/10/1923) Class G 5000 gallon tenders for Class A1 Nos. 2543-62, T.5253-72.

Tenders built later at Doncaster were to LNER designs, built in large numbers. These were:

Group Standard. designed at Darlington, developed from the NER 4125 gallons type, six-wheel, 3ft.-9in. wheels, wheelbase 7ft.-3in. + 6ft.-3in., carrying 4200 gallons and 7½ tons coal.

Also designed at Darlington, was a shorter version, 7ft. + 6ft. wheelbase, carrying 3500 gallons water and 5½ tons coal.

Eight-wheel 5000 gallon version based on GNR Class G designed at Doncaster, no coal rails.


Doncaster’s own first post Grouping design for Class P1 Nos. 2393/94 was R108 a non-standard tender, carrying 4700 gallons water and 7 tons coal, ordered as follows: TO46 (12/2/1925), T.5293/94.  The design incorporated certain features of the 8-wheel tenders, such as tank width and depth and certain Darlington features adopted for the Group Standard 4200-gallons type, including inside frames parallel to the main frames and 3ft.-9in. wheels.  The wheelbase was 6ft.-6in. + 6ft.-6in., providing extra overhang at the rear to make room for the booster under the cab.  The tender wheelbase was not altered when the boosters were removed (1937-38), but they were completely refurbished at Darlington (1946) prior to being used for Thompson Class B2.  The main frames were 23ft.-53/8in. long, 1in. thick set up 6ft.-1½in. apart.  The inside frames (more like strengthening plates) ran between the front and rear drag-boxes, were 20ft.-7¼in. long, 1ft.-3in. deep, ½in. thick and set up 4ft.-1in. apart.  The respective frames were 11¾in. apart.  The width over the side sheets was 8ft.-0½in. and that over the running plate was 8ft.-9in.  The overall length inside the main tank was 21ft.-2in., and was effectively in three sections.  The rear section was 10ft.-2in. long and 5ft.-2in. deep.  The middle section sloping downwards and inwards towards the front.  The front section was 4ft.-0in. long and 1ft.-35/8in. deep.  Thus coal stacked above the tank was self-trimming towards the front with the movement of the tender at speed.  The inside dimensions of the well tank were 12ft. long, 3ft.-9¾in. wide and 1ft.-91/8in. deep.  Splashers over the tender wheels were unnecessary as the rims of the tyres just cleared the tank bottom.

The length over the side sheets was 22ft.-6½in.  The width over the tank side sheets was 8ft.-0½in. and that over the running plate was 8ft.-9in.  The inside dimensions of the well were 12ft. length, 3ft.-9¾in. width and 1ft.-91/8in. depth.


The design was drawn out at Darlington who based it on their 4125 gallons type, with both outside and inside frame plates.  The main frames were ?ft-?in long, ?in thick and set up ?ft-?in apart. The inside frames plates were ?ft-?in long, ?in thick and set up ?ft-?in apart. Dimensions not obtained

Except where otherwise stated, these tenders had straight sides and vacuum brakes.

TO47/48/49 (26/3/1926) T.5295-5304, 5305-14, 5315-22, sent to Darlington for
Class D49 (Nos. 234/51/53/56/64/65/66/36/70/77, 245/81/46/49/50, 306/07/09/10/11,
318/20/22/27/35/27/29/52/36.  These tenders had stepped-out coping plates.

TO51/52 (about 8/1927) T.5456-65, 5466-75 for 1300 Series.
Class K3 Nos. 1300/12/18/31/45/64/65/67/68/86.  These tenders had Westinghouse air brakes.

TO58 (8/3/1932) T.5554-57 for Class O2 Nos. 2434-37.

TO65 (5/1935) T.5631-35 for Class V2 Nos. 4771-75.

TO70 (27/7/1938) T.5715-24 for Class V2 Nos. 4843-47.
4843-47 received T.5715-19/24, but T.5719-23 were sent to Darlington.

TO72 (12/12/1939), material ex-Darlington, T.5726-30 for Class V2 Nos. 4848-52.

TO73 (24/12/1939) T.5731-40 for Class V2 Nos. 3655-64 (actual fitting not confirmed).

TO74 (25/1/1940) 10 V2s, Nos. 3665-74.  Order transferred to Darlington (9/6/1941).

TO75 (3/6/1940) 10 O2s. Order cancelled, new O2s Nos. 3833-42 to receive D49 tenders.  These latter had been released by providing the D49s with surplus GCR 4000 gallon tenders.


All these tenders had straight sides and vacuum brakes.

TO55 (8/5/1931) T.5519-26 for existing J38, whose displaced 4200 gallon tenders would be renumbered T5542-49 for new Class O2 Nos. 2954-61.

TO57 (8/3/1932) T.5350-53 for existing J38, whose displaced 4200 gallon tenders would be renumbered T.5561-64 for new Class O2 Nos. 2430-33.

TO71 (18/10/1939) T.5714/25 for Class V4 Nos. 3401/02.        


These tenders are mentioned for completeness but Doncaster was not concerned with their design and construction.  The design was based on the ex-GER B12 tender with its short wheelbase (6ft. + 6ft.) and 4ft.-1in. diam. wheels.  The tenders attached to Nos. 2800-15 had Westinghouse brakes, Nos. 2816-42 had steam brakes and Nos. 2843-47 had vacuum brakes.  Nos. 2800-09 were built by N B Loco. Co.  The remainder were built at Darlington.   Later engines had Group Standard 4200 gallons tenders, with vacuum brakes. 


There were several varieties and the principle differences were clearly discernable.  For the purpose of this article, code letters have been introduced (though they had no official status) as follows:

GN GN-type, two coal rails above the coping plates.
NTC New-type Corridor, introduced 1928, no coal rails.
NT New-type Non-Corridor, introduced 1930.
SC Streamlined Corridor, introduced 1935, no beading running the length of the tender sides at the top.
SNC Streamlined Non-Corridor, introduced 1937.

Similar codes appear in “Locomotives of the LNER”, Part 2A (RCTS, 1973) though unfortunately in the Summary tables NTC and SC were lumped together as C, which is of limited use in particular to the model maker.

Except where otherwise stated, all these tenders had vacuum brakes.

TO44/45 (29/10/1923) GN T.5253-62, T5263-72 for Class A1 Nos. 2543-52, 2553-62.

In addition N.B. Loco. Co. built GN T.5273-92 for Class A1 Nos. 2563-82.
Of these T.5278-92 had Westinghouse air brakes.

The first New Type tender had a corridor down one side, to facilitate crew change en route on the non-stop “Flying Scotsman” service between London and Edinburgh.  To maintain the same 5000 gallons of water capacity the tank sides were 17in. wider, so that the overall width at 8ft.-9in. was same as that of the footplate.  This left just enough space for an 18in. wide corridor, on the right-hand side.  The overall length inside the main tank was 22ft.-2in., i.e. 5in. longer than in the earlier GN- type.  The frames were 2¾in. shorter at the rear end where the vestibule connection was provided.

TO50A (about August 1927) NTC T.5323-29 for new Class A3 Nos. 2743-49.

Instead attached to Classes A1 and A3 Nos. 4472/76, 2573/80/46/69/56.

TO50B (about August 1927) NTC T.5330-32 for new Class A3 Nos. 2750-52.
Instead attached to Nos. 2743-45, though they didn’t stay long with these engines.

The next requirement for a 5000 gallons tender was in December 1928 when an order was placed for a further eight Pacifics.  The tender design presented two choices: normal width providing 5000 gallons, or wider as in the corridor tender (NTC) but without the corridor thereby increasing the water capacity to 5450 gallons.  First of all Gresley agreed to the second choice and drawing R144 (10 May 1929) was sent to Gresley on the 16th for his approval.  He signed the drawing, which was then submitted to the Running Department for their comments.  They were less enthusiastic and the scheme was endorsed “not approved” (10 August 1929).  So the main tank of the New Type (NT) non-corridor tender for the Pacifics was 8ft.-0½in. wide as in the GN type, and the frame length was restored to 24ft.-1½in.

TO53 (2/1/1929) NT T.5476-83 for Class A3 2595-97, 2795-97, 2598/99.      

One further New Type Corridor tender was required for No. 10000 being completed at Darlington.  TO54 (8/3/1929) NTC T.5484 for Class W1 No. 10000.

Further New Type (NT) non-corridor tenders were ordered for new A3s and P2s.

TO56 (28/4/1932) NT for 5 Class A3, but cancelled (3/1933) due to industrial depression.

TO59 (4/3/1933) NT T.5565(/66) for new Class P2 No. 2001(/02). Order reduced to 1 (12/4/1933). The tank was of all-welded construction and manufactured by Metropolitan-Vickers at Trafford Park and delivered to Doncaster Works.

TO60 (7/11/1933) NT T.5567-75 intended for new Class A3 Nos. 2500-08.
Instead T.5567/68/70/71/73 attached to new Class A3 Nos. 2500-04.
T.5569/72/74 attached to Raven Class A2 Nos. 2402/01/03,
T.5575 attached to new Class P2 No. 2002.

TO61 (7/11/1933) NT T.5566 intended for new Class P2 No. 2002. 
Instead attached to new Class A3 No. 2505.

The tender side sheets were redesigned and the beading along the top was omitted, to give a smooth finish.  These were known as Streamlined Non-Corridor (SNC) tenders.
TO62 (7/11/1933) SNC T.5576-79 for new Class P2 Nos.

TO63 (11/12/1933) SNC T.5580-84 intended for Raven Class A2 Nos. 2400-04.
Instead T.5580/83 attached to Class A2 Nos. 2400/04
T.5581/82/84 attached to new Class A3 Nos. 2506-08.

NT tenders T.5569/72/74/80/82 were retrieved from withdrawn Class A2 engines
and attached to Class A3 Nos. 2599/98 (1936), 2746/52/53 (1937).

The next order TO64 (11/3/1935), T.5589-92 for Class A4 Nos. 2509-12.  These tenders were the Streamlined type but with Corridors (SC), and so had wider bodies (8ft.-9in. across) and shorter frames (23ft.-10¾in.) like the 1928 New Type Corridor (NTC).  Later, T.5590 was fitted with Timken roller bearings for its axle boxes (10/1938) which it retained to the end.

TO66 (about 1/1936) SNC T.5636-45 for the Classes A1 and A3 engines currently attached to NTC corridor tenders to release them for new Class A4 Nos. 4482-91. 
Attached 1936-37 to Nos. 2572/67, 2752,
2507, 2796, 2508, 2746, 4481, 2545/58.
This released NTC corridor tenders T.5323-32 for new 4482-91, which were instead  
attached to new Nos. 4482/85/88/89/84/90/98/87/83/86.  Note that No. 4498 “Sir Nigel Gresley” had been substituted for No. 4491.

TO67 (about 1/1936) SC T.5646-52 for new Class A4 Nos. 4492-98. 
Instead attached to Nos. 4491-97.  These were last Streamlined Corridor tenders built.  T.5647 was fitted with Hoffman roller bearings for its axle boxes (3/1938) which it retained to the end.  T.5648 was fitted with Skefko roller bearings for its axle boxes (9/1939) which it retained until August 1958 when some axle boxes reverted to plain bearings, the others remained fitted to the end.

TO67A (about 11/1936) SNC T.5667-69 for new Class A4 Nos. 4462-64.
Instead attached to Nos. 4462/63/65.

TO68 (11/1936) SNC T.5670-79 for new Class A4 Nos. 4465-69/99, 4500, 4900-02.
Instead T.5670-75 attached to Nos. 4466/67/69/99, 4500, 4900.
T5676-79 cancelled, remaining A4s were to receive (directly or indirectly) Streamlined (SNC) tenders from A1s and A3s released by New Type (NT) tenders from withdrawn Raven A2s.

TO69 (11/1936) SNC T.5680 for new Class A4 No. 4903.
Order cancelled.  Engine to receive the tender from a withdrawn Raven A2.

Further SNC tenders (with steam brake and therefore not interchangeable) were built after Gresley’s death.