TRANSPORTER BRIDGES
by John Ince
Webmasters note: My family and I have ridden on the Newport Transporter Bridge and can vouch for the fun of the ride!
Have you watched Auf Wiedersehen, Pet which screened on TV1 recently? If you did you
will have noticed that Oz is a bit older and wasn't scratching his b......s, you
know what I mean, quite as much. But he was there with the gang from the 1980s
TV series trying to make some cash out of dismantling the Middlesbrough
Transporter Bridge. And, you've guessed they made a complete, er, hash of it.
Perhaps you've had a ride on a
transporter bridge, or perhaps you have built a model of one using Super Model
Plan No 21, published first in 1928 and again in 1936.
There are two working transporter
bridges in the British Isles, while world wide there are seven that have
survived out of fifteen originally built .
Here is what the Meccano Magazine of
March 1928 had to say about the subject:-
There are few branches of engineering
that appeal more to imaginative boys than bridge-building. In it are to be found
some of the greatest structures and most creditable achievements in the history
of engineering, while in no other branch do we find the amazing adaptability of
the engineer emphasised in so many remarkable ways. In numerous cases the
engineers have had to face what seemed to be insurmountable difficulties in the
erection of their bridges, and they have shown undaunted courage in the face of
obstacles. They have responded to every demand made upon them, and have even
offered to bridge the English Channel between Dover and Calais! These facts
appeal to our imagination and make us enjoy reading of the trials and triumphs
of bridge builders.
There are many types of bridges, each
of which has some outstanding feature that makes it particularly suitable for
some special and individual purpose. These different types include arched
bridges of stone, cast or wrought iron girder bridges, cantilever and suspension
bridges, drawbridges, and transporter bridges. It is to the latter class that
the Meccano model illustrated on this page belongs.
The problems confronting a bridge
builder are indeed many and vary with each individual case. Because of this,
nearly every bridge of importance embodies some original feature that is found
in no other bridge, so it may be said that no two bridges are exactly alike. The
Tower Bridge with its pair of bascules, the Forth Bridge with its mile-long
roadway, and the high Menai Suspension Bridge, are all "bridges" but
each differs from the other in almost every particular owing to the
peculiarities of the local conditions.
When it is desired to bridge over a
river the local conditions must of course be taken into consideration before the
type of bridge can be decided upon. Should the river be navigable the bridge
must be placed at such a height that it will not interfere with the traffic on
the water. On the other hand, in cases where the river banks are almost on the
same level as the river the construction of a high bridge many feet above the
water line is not always practicable, for the cost and inconvenience of building
the necessary inclined approaches would be very great.
In some cases the difficulty has been
overcome by the construction of swing bridges (as over the River Tyne at
Newcastle) or drawbridges (as in the case of the Tower Bridge over the Thames)
but it may be said that the use of bridges of this type is confined generally to
comparatively narrow rivers. More over, the steering of large steamers through
the narrow opening of a swing bridge calls for considerable navigating skill,
and if a strong tide is running at the time, there is considerable risk of the
ship fouling the piers of the bridge.
Consequently in certain places, use is
made of transporter bridges. These consist essentially of a girder suspended at
such a height that it clears the tallest masts, and rails fixed to this girder
carry a trolley from which a car is suspended by steel cables. The car is moved
across the river by steam or electric power, and the level of the car platform
being the same as that of the approaches the road traffic passes direct from the
shore into the car and vehicles and pedestrians are carried bodily across the
river. The chief drawback to bridges of this type is, of course, the time taken
in loading and unloading the car. Also whilst the car is taking one load across
other road traffic may be held up until the car has completed the double
journey. Hence it is improbable that transporter bridges will be made use of in
the future except in places where the amount of road traffic is small.
The first transporter bridge was
designed in 1872 to cross the River Tees at Middlesbrough, but owing to
financial reasons the bridge was never built. For some years thereafter the
transporter type of bridge remained more or less a novelty until Palacis, an
architect of Bilbao, and Arnodin, a French engineer, took out a patent for this
system of bridge design. In 1893 they designed and erected a transporter bridge
at Portugalte, near Bilbao, the main span of the bridge being 148 feet above
high water level and built in the form of a suspension bridge with "
stiffening " girders. In 1897 a transporter bridge was erected across the
River Seine at Rouen. It has a span of 472 feet and is operated by electric
motors fixed to the top of the car. The towers are 280 feet in overall height.
Perhaps the most notable example of a
transporter bridge is that which crosses the River Usk at Newport in
Monmouthshire. The following are a few details of the principal features of the
bridge: the span between the towers is 645 feet and the girders are clear of
high water level by 177 feet. The car itself is 33 feet in length by 40 feet in
width and is driven by two electric motors each of which is of 35 h.p. The legs
of each end tower are hinged and sixteen steel cables, eight inside and eight
outside, suspend each of the two stiffening girders. Each of these cables
contains 127 wires and weighs 4 tons There is also a similar number of anchor
cables which are fixed to foundations consisting of large blocks of masonry
totalling 35,000 cubic feet. Each of the end towers rests on piers containing
some 19,500 cubic feet of masonry and concrete.
Another famous transporter bridge is
that which crosses the River Mersey between Runcorn and Widnes. This bridge is
of the suspended girder type and is of very massive construction. The structural
details of the Meccano model follow the lines of the Runcorn Bridge very closely
- most of the principal features of the actual bridge being reproduced in the
model.
A special automatic mechanism by means
of which the travelling carriage will traverse slowly from one end to the other
of the bridge and then reverse and travel back again is also included in the
model. Each time the carriage reaches the landing platforms at either end of the
bridge it pauses for a brief period before moving away again to the opposite
end. This process is repeated automatically so long as the electric current is
supplied.
The constructional details of the
towers and the main bridge are dealt with fully in this issue. The automatic
reversing gear and the construction of the travelling carriage will be described
and fully illustrated in next month's MM.
These model instructions were published
in 1928 as a Super Model Plan .
The transporter bridge featured in the
BBC programme was the one in Middlesbrough. This is not the one used for the
Meccano model; its construction is rather different.
The Middlesbrough Transporter
Bridge
The Middlesbrough Transporter Bridge was
built in 1907 by Cleveland Bridge and Engineering of Darlington and opened in
1911. It spans the River Tees and carries 750 people and 600 vehicles a day in
the carrying car which crosses over 160 feet above the river. The crossing takes
about two and a half minutes.
Passengers and vehicles are transported by means of a large moving platform
which is capable of carrying nine vehicles at a time.
Middlesbrough is in the north east of
England, about 50km south of Newcastle. The
Transporter Bridge crosses the River Tees and is 850 feet (255m) long,
225 feet (67.5m) high. It is a giant crane like structure, which is a cross
between a ferry and a bridge. Every year the bridge carries approximately
350,000 vehicles and 1,500,000 passengers .
There were two other transporter bridges
in England:
The Widnes-Runcorn Transporter
Bridge
This is the bridge on which the Meccano
Super Model is based, no doubt because it is not far from the home of Meccano in
Binns Road, Liverpool. The
Widnes-Runcorn Transporter Bridge was opened in 1905
to replace the previous ferry and to supplement the toll footbridge that ran
beside the railway bridge across the River Mersey.
The transporter design was chosen here
because the Manchester Ship Canal, running alongside the River Mersey at Runcorn,
carried tall ocean-going ships, which a low-level bridge would have obstructed.
At the time, the expense and engineering complexity of a high-level road bridge
were prohibitive, although a high-level railway bridge had been constructed some
years earlier (1868). The total cost of the Transporter Bridge was £130,000,
about one third of the cost of a high-level bridge.
The bridge was a magnificent feat of
Edwardian engineering. The span of the bridge across the Mersey was 1000ft
[305m]. The bridge towers stood 190ft [58m] above high water, and the main
cables supporting the bridge were 12in [300mm] thick. However, the suspended car
was very sensitive to adverse weather, and would often be closed down in high
winds.
Widnes Corporation had a controlling
interest in the bridge, and as the operators of the bus department, arranged a
fairly integrated transport service, with a Corporation bus stop only yards away
from the bridge ticket office. The bus service on the Runcorn side was privately
operated, and not so well integrated: the nearest bus stop was about a mile from
the bridge.
When a high-level road bridge was
finally built and opened on 21 July 1961, the
Transporter Bridge was closed. Demolition proceeded almost immediately.
The Warrington Transporter Bridge
The Warrington Transporter Bridge, which
was constructed in 1916, also over the River Mersey, is maintained in working
order but hasn’t been in use since 1964.
The Newport Transporter Bridge
Another working bridge in the UK is in
Wales. It is the Newport Transporter Bridge over the River Usk in Monmouthshire.
Built by a Frenchman Monsieur F Arnodin, the bridge was opened in 1906. It has
now become a tourist attraction. The bridge has a span of 645 feet measured from
the centre of each of its towers. The gondola is 33 feet long, 40 feet wide and
travels at 10 feet per second and can carry a maximum of 6 cars or small vans at
one time. The whole contrivance is driven by two electric motors.
The Newport Transporter Bridge is a
steel hybrid suspension/cable stayed bridge near the mouth of the River Usk. The
bridge stands some 75m tall with a clear span of 197m. In 1985, wire breakages
within the cables resulted in closure, and a level of holding maintenance was
established while funds were sought for more permanent remedial measures.
A £3m scheme to conserve and refurbish
the bridge began in 1992 and resulted in the bridge being reopened in December
1995. The project has ensured the survival of this landmark structure.
Other Surviving Transporter
Bridges
Elsewhere in the world Transporter
Bridges can be found in Rendsburg in Germany and in Portugalete (Vizcaya) in
Spain.
Who Designed These Bridges?
The construction of the two bridges
across the Mersey, the Widnes Transporter Bridge and the Warrington Bridge at
Bridge Foot were the work of John James 
Webster (1845-1914), a Warrington born
engineer. This eminent Westminster-based engineer had a worldwide reputation for
bridge and pier building, before he embarked on the design of Britain's first
transporter bridge early in 1900. He then built the Shepherds Bush Stadium for
the 1908 Olympic games before the Warrington Corporation commissioned him in
1912 to oversee the new crossing at Bridge Foot.
