British & Dominion Locomotives
Petrol Tractors
The
Motor Rail & Tramcar Company, who had been lobbying the War Office well before 1914,
supplied the majority of the British Army’s locomotives - eventually totalling well
over 1000 machines of various types. The British tractors comprised 5 basic types; 2
lightweight designs for use on very light (9lb/yd) rail; the McEwan Pratt 10hp & a Ford model ‘T’
car based Road/Rail “Crewe” Tractor, 2 distinct types of Motor Rail
petrol-mechanical and a Petrol-Electric Tractor.
Baguley 10hp Tractor in the Moseley Railway Trust collection
These
locomotives were a standard design of McEwan Pratt Ltd, E. E . Baguley Ltd having taken
over this firm in 1912 kept the name throughout the war period. Possibly the first
standard tractors to be delivered to France for British use, the initial 2 prototypes were
trailed at the Trench Warfare Research Unit in Audricq, near Calais in February 1916.
Weighing in at just under 2 tons, the tractors had a Baguley 10hp water cooled sidevalve engine and a patented Baguley 2 speed gearbox. Although 53 machines were delivered to the War Office, the design was not to prove very successful, contemporary reports stating that they were somewhat underpowered and difficult to handle. These tractors were eventually to find their niche shunting in base workshops where sharp curves and tight clearances were common.
Produced by the
London & North Western Railway Company, the “Crewe” tractor was a
lightweight convertible road/rail tractor based on a Ford Model T car– perhaps the
first type of road/rail vehicle. Designed with a maximum speed of about 13mph in rail
form, these vehicles had no reverse gears. They were equipped with an integral turning
plate, which would be lowered on to the track & enabled the car to be lifted and swung
round – in much the same way as the modern engineers’ Permaquip railcars, seen
on the national rail network today.
The concept is
said to have been derived in late 1916, by one of the daughters of Mr Bowen Cooke, the
then CME of the London North Western Railway. Whilst in Paris, she overheard a
conversation of an officer on leave, complaining about front-line transport. The idea was
to design a vehicle, which could quickly move by road to any given point, then easily
convert, and run the remainder of a journey on lightweight track – often laid over
heavily shelled devastated areas.
The Crewe
tractors were constructed under a Motor Transport requisition, as they were nominally road
vehicles. As a result they were assigned MT (Motor Transport) numbers rather than LR
(Light Railway). It is not certain how many of these vehicles were actually built. The
surviving records from British Rail (successors to the LNWR) show 132, whilst the WD
records show 138. There were several Ford 1ton lorries converted to rail use, which may
account for the discrepancy.
One of the
founders of the Motor Rail & Tramcar Company, Mr T. D. Abbott, had visited Germany in
about 1911 and was alarmed at the stockpiles of light railway equipment for army use,
including internal combustion locomotives. Worried that there was no British equivalent
for use on temporary military supply railways, he set about designing such a machine. The
first tractor was produced in 1915, although it was to be 1916 before the War Office
issued the contracts for equipping trench railway systems.
20hp Simplex
Tractor
Moseley Railway Trust 20hp Bent Frame Tractors at the Ffestiniog Railway
When the
contracts were finally issued, the War Office required “Petrol Trench Tractors”
of 600-mm gauge which were capable of drawing 10 to 15 Tons at 5 miles per hour; the MRTC
tendered for, and were successful in gaining this initial supply contract.
This type of
tractor, often known as a “bow” or “bent” frame simplex (due to the
elongated octagon shape of the main frames), was one of the most successful petrol rail
tractors to be produced in any quantity. 820 of these machines were ordered, with well
over 580 delivered & seeing active service in all theaters of war.
The success of
the design was due in no small part to the patented Dixon-Abbot gearbox, providing 2
speeds in each direction. This was mounted on a frame built of channel steel, and was
coupled to a 20hp, two-cylinder water-cooled Dorman 2JO petrol engine.
Moseley Railway Trust "Protected" 40hp Simplex - featuring in the UK TV program 'Salvage Squad' Photo - John Rowlands
With the success of the 20hp
tractor well proven, Motor Rail were again approached by the War Office to submit a design
for a larger 40hp machine to work up to frontline areas, often on exposed sections of
track.
The design would appear to have
been accepted with no prototypes built, although the second 40hp machine built (MR381, an
“Open” type) was dispatched to the Woolmer Instructional Military Railway at
Longmoor, Hants – presumably for initial trials.
The design of the 40hp machine
was based very closely on its smaller 20hp cousin, again utilising the patented
Dixon-Abbot gearbox. This time the power was supplied by a 40hp, four-cylinder
water-cooled Dorman 4JO petrol engine. The main
frames, again of an elongated octagon shape, were built out of heavy plate, rather than
channel. The “Open”
tractors weighed 6tons 3cwt, rising up to 7tons 2cwt for fully Armoured. A total of 317 of
the 40hp type tractors appear to have been supplied to the War Office, for service in
various theatres of war including France, Italy, Salonica (Greece) & Egypt.
Designed for
operation in forward areas, the 40hp tractor was supplied in three variants; “Open”,
“Protected” and “Armoured”. The “Open”
consisted of heavy steel curved end plates covering the vital parts and a light canopy
roof on height-adjustable pillars. The “Protected” had all this plus
shrapnel-proof side doors and visors all round. The “Armoured” version was
similar to the “Protected”, but in addition had an armour-plated roof, which
curved down at each end and had slits for the driver to look through - rather like a tank.
Reputedly, a .303” caliber bullet shot at 50 yards range would make only a small dent
in the plate!
When originally
conceived, the War Office plans were for some 800 steam locomotives (covered in the next
thrilling installment!) to work “main line” supply trains, then handing over to
overhead-wire electric traction (200 off) to work in the exposed forward areas.
The overwhelming
success of the initial Simplex tractors seems to have made the War Office revise their
plans, resulting in the cancellation of the overhead line equipment & generating
stations. This was perhaps a wise move, as camouflaging the overhead equipment in forward
areas would have required some significant ingenuity!
The War Office
would appear to have covered themselves incase the Petrol Tractors proved to be unreliable
in the longer term. The 200 electric locomotives were built, but as self-contained units
– comprising a Dorman 4JO petrol engine, generating set and traction motor. In
addition, they could run equally as well as pure electric locomotives, drawing power from
overhead lines.
The
Petrol-Electric tractors were built by 2 manufactures, British Westinghouse Ltd & Dick
Kerr Ltd. British Westinghouse actually undertook the initial design work, and were
awarded the contract for the first 100 machines. By February 1917 the first 3 of the
production Petrol-Electric (believed to be Dick Kerr) tractors were sent to the then North
Wales Narrow Gauge Railway (later Welsh Highland Railway) near Caernarfon, for extensive
trials. It is believed that these were later sent on to the WD Testing & Training
depot at Longmoor – eventually going to France.
In service
the Petrol-Electric tractors seem to have been well liked, although they were less stable
when in motion than their Motor Rail cousins. The appeal appears to be due to their
ability to function as mobile electrical generating stations – powering all most
anything in the field.
As further pictures and drawings become available I will endeavor to further enhance this area. Click here to Contribute to this section - please replace (AT) with @ to make e-mail work.