LSWR M7 Class


This was a numerous and successful breed of tank engine, originally procured to speed up LSWR suburban services. It followed in the footsteps of an earlier 0-4-4T design laid out by Chief Draughtsmen at Nine Elms, under the direction of William Adams, the company’s then Locomotive Superintendent. Adams claimed he felt safer riding a bogie engine, and a four-coupled design with large driving wheels would remain stable at relatively high speeds. His counterpart on the LB&SCR, William Stroudley, was keen to forgo the 0-4-4 wheel arrangement, for he considered that when running forwards, the lateral control springs of the rear bogie had too strong an influence over the front driving wheels. Indeed, in terms of tender locomotives, bogie designs had generally been avoided because at the time (circa 1885), the largest turntables in use could only just about accommodate an 0-6-0 engine and its tender. Enlargement of many turntables was considered too costly, because it involved expensive alterations to other infrastructure. Unperturbed by Stroudley’s concerns over a bogie tank engine, Adams introduced the Class 415 ‘’Radial’’ Tank 4-4-2 in 1882, the Class A12 0-4-2T in 1887, the Class T1 0-4-4T in 1888, and finally, the Class 02 0-4-4T in the following year. These types were primarily employed on intensive commuter services from Waterloo, prior to electrification in the following century.

Adams retired from the LSWR in May 1895 through ill health, and in the following August Dugald Drummond became the company’s Locomotive Superintendent at Nine Elms. Born on 1st January 1840, Drummond had a complicated employment history up to this time, having started his career on an apprenticeship with Glasgow-based Messrs. Forest Barr, a general engineering firm. He subsequently gained railway experience with the Caledonian & Dunbartonshire Railway in Western Scotland, where his father was employed as a permanent way inspector. In 1862, he was employed at the Canada Works, Birkenhead, of Mr Thomas Brassey, who ran a civil engineering firm. The company was primarily a railway builder, being awarded contracts throughout the world to undertake works ranging from forging cuttings and creating embankments, to laying track and building viaducts. Drummond left Birkenhead in 1864, returning to his native Scotland to become Foreman at the Cowlairs Works of the Edinburgh & Glasgow Railway (E&GR). It was here where he first met William Stroudley, another giant of locomotive engineering. Stroudley had joined the E&GR in 1861, taking the post of Works Manager at Cowlairs at the age of 28.

The E&GR was absorbed by the North British Railway on 1st August 1865, but Stroudley had earlier left for the Highland Railway on 19th June of that year. He was appointed Locomotive & Carriage Superintendent at the company’s Inverness Works, and took with him his Foreman from the E&GR, Drummond. Stroudley had a five-year tenure with the Highland Railway, during which time scope for new locomotive development was virtually non-existent due to the impoverished state of his employer’s finances. Most of Stroudley’s work was thus concentrated on improving and maintaining the existing locomotive fleet, although he managed to produce one new type of locomotive, an 0-6-0T variant, which he would later perfect on the LB&SCR. Stroudley became Locomotive Superintendent of the LB&SCR at Brighton in 1870, where he soon began a large-scale standardisation programme of the company’s motive power. Facilities were modernised in the form of new, reorganised works and engine sheds, and he was again joined in his move south by Drummond. The latter returned to Scotland in February 1875, when he was appointed Locomotive Superintendent of the North British Railway at Cowlairs Works, Glasgow. In June 1882, he moved to the rival Caledonian Railway (CR), being appointed Locomotive Superintendent at St Rollox Works. It was here where Drummond initially toyed with the idea of developing a four-coupled tank locomotive with an 0-4-4 wheel arrangement and trailing bogie; indeed, 24 tank engines of this type, with 5-foot driving wheels, were built for the CR between 1884 and 1891. In 1890, prior to completion of this production run, Drummond resigned from the CR and made a drastic move overseas to Australia, where he founded the ‘’Australasian Locomotive Engine Works’’ in Sydney. This transpired to be a fruitless exploit, and within a year he returned to Britain to start a second business, that of ‘’Drummond D. & Son’’. This evolved into the ‘’Glasgow Railway Engineering Company’’, which Drummond left in August 1895 to take up the penultimate railway appointment in his career – that of Locomotive Superintendent for the LSWR at Nine Elms (he was promoted to Chief Mechanical Engineer in January 1905).

In his new post, Drummond immediately set to work on a new class of tank engine, with the intensive suburban services from Waterloo in mind. As per those engines procured during his time with the CR, he opted for an 0-4-4 arrangement, although with larger driving wheels of 5-foot 7-inch diameter. In April 1896, the decision was taken by the LSWR Board to tender out the contract to build an initial batch of 25 of these engines, numbered in the series 242 to 256 and 667 to 676. The cheapest quote received was from Sharp Stewart & Co. at £2475 per engine (£213,000 at 2008 prices), significantly higher than what the company had envisaged. As a result, all locomotives were instead built in-house, the vast majority at the LSWR’s Nine Elms Works, at a cost of £1400 each (£121,000 at 2008 prices). Eventually, fourteen separate orders with a cumulative total of 105 engines were put into production over a fourteen-year period. During 1909, Nine Elms Works was replaced by a completely new complex at Eastleigh, and it was at the latter where the final ten Drummond tanks were completed.

The engines were designated ‘’M7’’, which derived from the alphanumerical order number of the early batches at Nine Elms Works. When the first ‘’M7’’ Tanks entered service in March 1897, the LSWR’s suburban locomotive fleet had reached saturation point. There already existed a large number of relatively new tank engines on commuter workings, procured under the leadership of Drummond’s predecessor, William Adams. Consequently, many of the first ''M7'' engines were sent to far-flung corners or the LSWR network, as distant as Exeter and Plymouth in the west, and a little closer to the capital, at Bournemouth, Salisbury, and Portsmouth.

The fifty locomotives built from 1903 onwards featured frames 15-inches longer than earlier batches; this produced a long front overhang, under which an air reservoir was eventually fitted. In addition, engines prior to 1903 were equipped with a lever reverser, whilst later batches were fitted with a steam reverser. Post-1903 engines were also fitted with a feed-water heater. The latter was simply used to pre-heat the water before it went to the main boiler. Drummond’s past involvement in Scottish railways was reflected by the incorporation of deep-toned organ pipe whistles, as found on engines of the CR. This was, however, a short-lived feature which was soon replaced. A second Drummond innovation that had brief use on these engines was the spark arrestor. The first batch of 25 engines were equipped with a complicated arrestor system, which filled up the firebox with a series of hoods and deflecting plates. The spark arrestor was there to prevent burning embers and sparks from escaping through the chimney, where they could pose a fire risk. The size of the spark arrestor required a conical smokebox door to be fitted to engines, but subsequent builds without this cumbersome set-up were equipped with flatter doors.

An early incident involving an ‘’M7’’ Tank occurred on 6th March 1898, when No. 252 suddenly left the rails two miles north of Tavistock station, Devon. It was hauling the 5:30 PM Exeter to Plymouth service at an estimated 40 MPH. Trailing the engine were seven vehicles (a covered carriage truck; two third class carriages; two guard’s vans; two bogie composites), which also derailed, and the formation came to a stop after travelling 210 yards through the ballast. There were no injuries to passengers or the crew, but the carriages sustained slight damage; in addition, the engine had its brake gear torn off. A Board of Trade report concluded that the cause of the accident was obscure and no single explanation for it was forthcoming. It was noted that the locomotive was brand new in June 1897, the carriages had recently been overhauled, and the route itself was of recent origin, too. No faults were detected in the engine’s wheels or springs during examination after the incident. However, previous experience had shown that whilst these engines were good hill climbers, they became unstable at speed when travelling downhill with slack couplings, and had a severe effect on the track. Given that the train had been travelling downhill, it was suspected that it had been running at a speed far greater than the 40 MPH quoted by the driver.

Displacement and a Curious Rebuild

In 1913, the LSWR announced electrification of its suburban lines as far out as Guildford, via Woking, Cobham, and Epsom, using the 600 Volt D.C. third rail system. In addition, Hampton Court and Shepperton branches were to be similarly treated, as were the Kingston and Hounslow Loops. The opening and electrification of the Piccadilly and District Lines respectively, combined with the spread of tramways, had seen patronage of LSWR suburban services drop significantly. Electrification was seen as the only way forward, and electric services commenced on the majority of the aforementioned routes as follows:

Naturally, this eradicated much steam from the LSWR suburban area, but the Windsor Line remained unconverted and indeed, no further electrification took place until after the Grouping. Drummond’s Tanks became increasingly used for branch line duties; for this, from 1912, engines started being equipped with apparatus for push-pull working. As the name suggests, this enabled locomotives to push or pull their carriages (which had to be similarly modified) in service, and negated an engine run-a-round manoeuvre at the end of a journey. The driver was situated at least a carriage length away from the engine, but in the cab of the trailer could be found a duplicate regulator handle, which allowed the movement of the locomotive to be controlled. Later systems had the duplicate handle connected to the regulator in the engine cab by means of a shaft, which ran the length of the coach and then projected up through the footplate, to be pinned to the handle. The early LSWR system, however, devised by Drummond, involved a more primitive cable and pulley system. Wires ran along the boiler between the chimney and dome, and just under half the class were so modified. Until completion of the suburban electrification scheme by the Southern Railway, a push-pull service was maintained between Claygate and Guildford.

On 8th November 1912, Drummond died at age 72 at his home in Morven, Surbiton, as a result of tragic and unusual circumstances. He had sustained severe burns as a result of scalding his feet with boiling water. The burns, left untreated, then transformed into gangrene, which in turn required amputation. Drummond opted out of an anaesthetic and consequently died of shock. He was replaced by Robert Urie, who had originally joined the LSWR in 1897 as Works Manager at Nine Elms, after a move from the Caledonian Railway. Urie was a respected all-round locomotive engineer, and although noted as less autocratic than his predecessor, remained a formidable character among the foreman at Eastleigh Works. He had earlier held the post of Chief Draughtsman on the CR. Urie remained as CME until the 1923 Grouping, during which time he undertook a rebuild of ‘’M7’’ Tank No. 126. In 1921, this engine was equipped with enlarged cylinders and a superheated boiler, featuring an elongated smokebox and a Urie stovepipe chimney. Reportedly, the rebuild produced an engine which consumed less coal and water than its classmates, but at the cost of raising the centre of gravity to make high-speed running unstable. In addition, oil usage was also unusually high, and the engine was deemed too heavy for many of the LSWR’s suburban lines. As a result, No. 126 was confined to the role of Waterloo station pilot, and hauled empty carriage stock between Waterloo and Clapham Junction Carriage Sidings. The results from the experiment put a stop to rebuilding a further twenty examples in the same fashion.

In 1920, ‘’M7’’ Tanks started to receive enlarged coalbunkers. When new, these engines could hold 3-tons of coal, but modification resulted in bunkers being heightened by the addition of extra metal rails, raising capacity by half a ton.

Southern Railway Takeover

The LSWR was absorbed into the Southern Railway on Grouping in 1923, accompanied by the neighbouring LB&SCR and SE&CR. At this time Urie retired, and Richard Maunsell, a former SE&CR man, was appointed as the first CME of the SR. It was during this period that steam took a rather secondary role, the SR Board being preoccupied with electrification. On the South Western Section, public electric trains reached Dorking North and Guildford on 12th July 1925, and the Windsor lines, too, became electrically worked on 6th July 1930.

The ‘’M7s’’were the largest single class of tank engine to be inherited by the SR, and under this company’s auspices their operational scope increased. The LSWR numbering series was retained, but between 1923 and 1928 an ‘’E’’ prefix was displayed in front of the number (simply denoting ‘’Eastleigh’’). Several of the type were cascaded to the Central Division which, in spite of the electrification mania of the 1930s, still retained large pockets of un-electrified railway. Typically, they were employed on push-pull branch services, featuring on those rural lines around Oxted and Tunbridge Wells West.

The early Drummond cable and pulley push-pull system was vastly improved upon, given a series of malfunctions that led to the equipment’s removal from engines. Push-pull workings could be found on LMS and GWR systems (being known as ‘’auto-trains’’ on the latter), but it was perhaps on the SR network where they were most abundant. From 1929 onwards, ‘’M7’’ Tanks started being fitted with a compressed air system for such trains. This involved attaching a Westinghouse pump to the right-hand side of the smokebox, a regulator-operating cylinder in front of the water tank on the same side, a back-pressure cylinder on top of the same tank, and finally, a large air reservoir underneath the long front overhang of the frames. The compressed air was required to work the locomotive’s regulator when the train was being driven from the cab of a trailer. The back-pressure cylinder was there as a safety device, keeping a reserve of low-pressure air constantly exerted on the underside of the piston in the regulator-operating cylinder. Thus, should an air supply failure occur (i.e. due to a broken pipe), this reserve pressure would be enough to return the piston up in the cylinder and shut the regulator. The Westinghouse pump was driven by steam from the boiler and, should too low a pressure be detected in an air reservoir elsewhere on the tank engine, the pump cut in and puffed away until the pressure had been restored to the required level.

In May 1937, unique ‘’M7’’ No. 126, the Urie rebuild, was withdrawn from service as a non-standard engine. It was dismantled and many of its components re-used to maintain the rest of the ‘’M7’’ fleet, notably No. 254, which receive its long frames. In the following November, Oliver Bulleid replaced Richard Maunsell as CME of the SR.

British Railways: The Twilight Years

Of the 105 ‘’M7’’ Tank Engines built, all but one member, No. 126, were absorbed into British Railways ownership in January 1948. SR modifications to date had included the fitting of compressed air push-pull gear to around thirty members of the fleet, and the addition of plating within the rails of the coalbunker, to prevent small lumps of coal from escaping. A second engine of the class, No. 672, had a BR career of just 3½-months. On 13th April 1948, the engine propelled four loaded coal wagons onto the hydraulic hoist of the Waterloo & City line at the London terminus. The lift began to fall and took all four wagons and the engine with it, the latter’s driver and fireman jumping clear. The coal wagons were smashed up at the foot of the lift shaft and the engine landed on them upside down. No. 672 was dismantled in situ and its parts used as spares for the rest of the fleet.

General withdrawals commenced in 1957, with No. 30042 disappearing in June of that year. At this time, the type was spread throughout the Southern Region, allocated to every ‘’A’’ shed bar those of the South Eastern Division. Their demise gathered a pace thereafter, and in 1959 ‘’M7s’’ were ousted from Waterloo pilot duties. They were replaced by a mixture of 0-6-0 WR Pannier and BR Standard 2-6-4 Tanks. On the advent of the 1960s, push-pull workings were rapidly decreasing as branch lines completely lost their services or, for those which retained trains, were dieselised. By May 1964 just nine ‘’ M7’’ Tanks remained in service, all of which were withdrawn during that month. Of the entire fleet of M7 engines which remained in existence, No. 30245 was the eldest, having been completed in April 1897 and withdrawn over 65-years later, in November 1962. As a result, it was selected for preservation as part of the National Collection. A second ‘’M7’’, No. 30053, was also cherry-picked for preservation, this time privately. It was one of the last nine of the type to be withdrawn in May 1964, and had been in service since December 1905. After a period of sitting out in the cold at Eastleigh, the engine was cosmetically restored and shipped to the United States in April 1967, for exhibition at Steamtown USA, Scranton, Pennsylvania. There it remained for twenty years, out in the open, the sun bleaching its paintwork and leaving the humble tank engine in a very sorry state. Happily, it was purchased by the Drummond Locomotive Society in 1987, and in that year returned to Britain. After a thorough restoration, it once again moved under its own power on the Swanage Railway, Dorset.

November 1958

In fine external condition, No. 30051 is seen at Redhill Shed. At this time, the locomotive was allocated to Horsham, both the shed there and that at Redhill coming under Brighton's "75" series. This was one of thirty-six of the "M7" Class to be equipped with a compressed air system for push-pull working. © David Glasspool Collection

3rd August 1959

A grubby No. 30039, still wearing early BR "Cycling Lion" crest, is seen at Fratton, the shed to which it was allocated in the year of this photograph. The locomotive had disappeared from lists by January 1963. © David Glasspool Collection

April 1960

No. 30248 is seen shunting empty carriages (the vehicle in view being a Bulleid design) in the unmistakeable environs of Clapham Junction. It was at this time that ex-GWR "5700" Pannier Tanks started arriving in force at Nine Elms to replace the "M7" Tanks on empty stock workings to and from Waterloo. © David Glasspool Collection

7th October 1962

A little grubby, but still in fine fettle, No. 30032 is depicted on the shed lines at Eastleigh. As of 30th January 1963, the Ian Allan ABC locoshed book has No. 30032 as being allocated to Feltham (70B); by the subsequent edition current to 11th November of that year, the engine had disappeared from lists. © David Glasspool Collection