DAYS OF STEAM

These included Foden, Leyland, Thorny croft and Sentinel, whose
internal combustion engined vehicles stand in the front rank
today.

Excluding an order for 112 steamers built by Sentinel in 1950
for the Argentine Government, this type of vehicle was not produced
in this country much after 1933. The main reason for its demise was
the restriction of gross laden weights.

There were two principal classes of steamer, known respectively
as the overtype and under type, the former having its engine on top
of the boiler and the latter with its engine under the boiler.
Boilers, too, were classified as being either of the vertical type
or locomotive pattern and throughout the years the subject of
boilers was keenly debated.

It, one of a famous line of steamers, this Yorkshire 5 tonner,
whilst not a thing of beauty, was notable for its consistent
performance. The design of the boiler was one of its outstanding
features, being a double-ended locomotive type.

This Foden model attained great popularity in 1926. It was
followed by the Foden Speed Six fitted with giant pneumatic tires.
It sold well up to 1931.

The last models to be produced by both Foden and Sentinel were
of the under type with vertical boilers, although up to 1927 these
makers, along with numerous others, had adopted the overtype engine
with locomotive or horizontal boiler. Although the locomotive type
boiler was a good steamer, it suffered from the disadvantage, when
used in a road vehicle, that in climbing or descending a steep
gradient the fire tubes would temporarily be above water level.

This drawback did not apply to the vertical boiler or to the
special type of steam generator fitted to the Yorkshire steamer.
This was of the double ended locomotive type and, being mounted
transversely, was not affected by road gradient.

One of a batch of 112 Sentinel steam vehicles built for the
Argentine Government in 1950. A road-test report of this model was
published in The Commercial Motor on January 6, 1950. The payload
was 13 tons.

One of the most famous makes of steamer was the Yorkshire, and
this is a typical 5 ton model of the 1905 era. It ran on cast-steel
wheels, and because its gross weight was over 8 tons it was
restricted to a maximum speed of 5 mph. All Yorkshire steam wagons
had a double-ended, fire tube boiler placed transversely across the
frame, and this particular vehicle had twin cylinders, one on each
side of the frame underneath the body floor.

The all British motorbus made news in 1905 because of the large
number of German built chassis in use at that time. Although
bearing a Birmingham registration plate, this Thorny croft 24 HP
bus was owned by the London Motor Omnibus Co., Ltd., and leased by
them to the Birmingham Motor Express Co., Ltd. The total passenger
capacity was 36, including two alongside the driver, and the bus,
which had a top speed of 12 mph, cost 900, with tires and body.

A novel feature of this 1905 Maudslay double decker was that the
40 HP engine had mechanically operated inlet and exhaust valves, an
overhead camshaft being employed. The bus was built for the
Scottish Motor Traction Co., Ltd., and carried 16 passengers in the
saloon and 18 on top. Ventilation was stated to have been
‘carefully considered,’ but upper-deck passengers are
likely to have called this an understatement. The radiator cowl was
neat for this period and the mud guarding was thought to be
particularly comprehensive.

Specialized transport for the Army; a 1905 ambulance built for
the Royal Army Medical Corps. The chassis was a Straker Squire and
was similar to the bus chassis, but had a shorter wheelbase. The
sides, roof and floor were lined with 1 inch felt, presumably to
deaden the noise of the vehicle in motion, and a slight form
of.

It was not until the later years in the life of the steamer that
attempts were made by some manufacturers to tidy them up. For
example, the Foden Speed 12, produced in 1930, was similar in
appearance to a modern oil engined six-wheeler. The boiler was
behind the driver, so that it was not difficult to bring the
frontal styling into line with that of current combustion engined
vehicles.

Apart from Government policy, driver recruitment presented
difficulties, as the driver of a steamer had to be of an entirely
different calibre from those who had started out on petrol engined
vehicles. The fire had to be carefully watched, as did the water
level in the boiler if the correct head of steam for all
emergencies was to be available.

In the Clarkson steam vehicle, which was produced both for
passenger and goods work, a water tube boiler was employed. On bus
work this was oil fired, but in 1914 a coke fired version was
introduced on a goods chassis. The coke was preheated and fed to
the boiler automatically.

Although a steam driven vehicle is ideal in many ways, there is
little chance of its revival unless improvements can be made in
steam generation.