PENYDARREN TRAMROAD
HEW 705: SO 056 070
to ST 085 950
The Penydarren Tramroad,
engineered by George Overton and opened in
1802, has a unique place in railway history. On it, on 21 February 1804, what is
generally regarded as the first journey by a steam locomotive was made by a
machine built by Richard Trevithick. The L-section cast iron rails were 3 ft long,
weighing 56 Ib each, laid on stone blocks to a gauge of 4 ft 4 in. over the out-
sides of the flanges. The rails proved too fragile for the weight of the locomotive,
so that although the experiment showed the possibilities of this new form of
traction it also demonstrated that these could not be fully realized until a much
better track became available - which did not happen until 1825, on the
Stockton and Darlington Railway.
The Glamorganshire
Canal was completed between Merthyr Tydfil and the sea
at Cardiff in 1798. In consequence of disagreements between Richard
Crawshay, whose Cyfarthfa ironworks were best served by the canal, and the
other ironmasters of Merthyr, a tramroad was constructed from Samuel
Homfray's Penydarren works to a point on the canal at Abercynon (the
Navigation Hotel nearby was once the offices of the Canal Company). This route
effectively bypassed part of the canal route, particularly ten sets of locks north of
the junction at Abercynon.
From its southern terminus
at Abercynon (ST 085 950) the route of the
Tramroad runs along the eastern bank of the River Taff. Near Quaker's Yard the
river was crossed by timber bridges at ST 094 963 and ST 090 966 (HEW
799). About 1815, these were replaced by segmental, nearly semicircular,
masonry arches of 60 ft span and 9 ft wide, which have parallel rings about 18
in. deep composed of 2 to 3 jn. flat stone voussoirs similar to Pont y Gwaith
(HEW 800), and indeed, Pontypridd (HEW 27). The old alignment can still be
traced.
Further on, the Tramroad
was eventually crossed by the Taff Vale Railway on a
viaduct (HEW 801, ST 089 965). The section between Quaker's Yard and Pont
y Gwaith follows the deep valley of the Taff through pleasantly wooded country.
North of Merthyr Vale
the route crosses to the east side of the A470 trunk road
and continues to Merthyr where its course is perpetuated in the names of two
streets, Tramroadside South and Tramroadside North.
At SO 056 070, near
the point of termination, there is a memorial to Richard
Trevithick.
TAFF VALE RAILWAY
HEW 1219: SO 052 057
to ST 190 750
At Pontypridd the River
Taff is joined by the River Rhondda before flowing on to
Cardiff. Between the two rivers lies the valley of the Gynon, a tributary of the Taff.
At the turn of the
18th- 19th centuries the discovery of iron ore along the heads
of the valleys and coal in the valleys led to the establishment of ironworks, as at
Cyfarthfa and Dowlais near Merthyr Tydfil, and to a rapid expansion in coal
mining. These industries required means of transport for the raw materials and
for the finished products. The Glamorganshire Canal from Merthyr to Cardiff was
built between 1790 and 1798 to give communication with the sea, but in general
the South Wales countryside did not really lend itself to the development of
canals, and so there was a great proliferation of horse tramroads such as
Penydarren (HEW 705).
By 1830 canals and
tramroads were proving inadequate, so in 1835 the Merthyr
ironmasters engaged I. K. Brunei to construct the first major commercial railway
in South Wales. An Act of June 1836 authorized a single 4 ft 8y in. gauge track,
24^- miles long, with six passing places, from Merthyr, at the head of the Taff
Vale, to Cardiff, where dockland development was beginning.
Major works included
a rope-worked incline at 1 in 19 north of Navigation
(Abercynon); a masonry viaduct at Pontypridd (HEW 1220, ST 071 900) with a
skew span of 110 ft across the Rhondda; and the six span masonry viaduct
across the Taff and the Penydarren Tramroad at Quaker's Yard (HEW 801).
This is unusual in having octagonal piers with deeply chamfered arches. There
were three other crossings of the Taff, at Whitchurch and to the north and south
of Taffs Well. The southernmost sixteen miles were opened in October 1840
and the line was opened throughout on 28 April 1841.
In the course of time,
coal became the dominant traffic. The Taff Vale Railway
expanded into the Cynon valley from 1845; by 1856 it had reached Treherbert
near the head of the Rhondda Each and in the following year the line to Merthyr
had been doubled. Before the end of the century the company had penetrated to
Llan-trisant, Cowbridge and Aberthaw and beyond Cardiff to Penarth, where it
eventually owned the docks, and to Barry. The railway now had adequate outlets
to the sea, but, in spite of some not entirely satisfactory transfer arrangements
built at Cardiff, was not able to make use of the broad gauge South Wales
Railway (HEW 1191) to move its traffic eastward across the Severn into
England until the conversion of that railway to standard gauge in 1872.
The Newport Abergavenny
and Hereford Railway Co. exploited this situation to
gain a share of the lucrative business by pushing their Taff Vale extension
westwards to join the TVR at Quaker's Yard. It was over these routes that there
was a massive movement of coal northwards in the First World War to fuel th
Navy at Scapa Flow.
The Taff Vale being
first in the field, was able to choose the easiest routes m
difficult country. Later railways competing for the lucrative coal traffic had to
contend with a harsh topography sometimes having to move from valley to
valley, and at the expensi of long viaducts and tunnels. It is little wonder, then,
that the surviving lines of British Rail in the area largely use the pioneering
routes of the Taff Vale Railway.
PONTYPRIDD BRIDGE
HEW 27: ST 074 904
There are a number
of engineering works in the vicinity of the Taff and Cynon
valleys north of Pontypridd
No study of bridges
- and especially masonry arch bridges -would be complete
without a reference to William Edwards's famous arch across the River Taff at
Pontypridd. His first attempt in 1750, a multi- span bridge, was washed away in
a flood after only two years. Edwards then decided to span from bank to bank,
but again his arch was washed away in a flood even before the centre was
struck.
His next attempt was
also doomed to failure. The span 140 ft involved a rise of
35 ft and this meant a great weight of filling over the haunches compared with
the crown where there was only the arch ring and the parapets. During the
construction of the spandrel walls the excessive weight near the abutments
forced the crown upwards and the bridge again coliapsed. Fortunately this was
not a sudden failure and Edwards had time to observe the mode of collapse.
Jervoise has described
the third and successful single span as follows:
'Edwards then rebuilt the bridge to the same design except that he placed at
each end three cylindrical holes graduated in size, the largest being 9 ft in
diameter, to relieve the arch from the pressure of its haunches'. The spandrel
infilling was of charcoal, for further lightness.
This scheme proved
successful, and the bridge, which was completed in 1755,
still stands.
The bridge soffit is
an almost perfect arc of a circle 89 ft in radius and the arch
ring has a depth of construction of only 2j ft. The relatively large rise at the crown
resulted in steep slopes at either end of the bridge and this caused serious
problems for heavy carts - both during the ascent and descent. A modern bridge
has been built alongside and Edwards's masterpiece is preserved and used for
pedestrians only. It is 11 ft wide between parapets.
BERW ROAD BRIDGE, PONTYPRIDD
HEW 620: ST077 911
The Berw Road Bridge,
which crosses the River Taff about half a mile upstream
of William Edwards's masonry arch bridge, is one of several early reinforced
concrete bridges in South Wales built on the Hennebique system.
The bridge has a central
clear span of 116 ft and side spans of 25 ft. The width
between parapets is 26 ft.
The main span has three
parabolic arched ribs, at 12 ft centres, cross-braced at
intervals. The longitudinal beams supporting the deck are supported by columns
off the ribs over the outer thirds of the span and the arch itself serves as direct
support to the deck over the middle third.
The side spans have
their outer main beams arched to match the centre span.
The bridge was built
in 1907 to the design of L. G. Mouehel and Partners. The
deck was reconstructed in recent years.
PONTYGWAITH
HEW 800: ST 080 975
Pont y Gwaith is a
masonry bridge of 55 ft span, 15 ft 9 in. rise, over the Taff
about a mile north of Quakers Yard. It has several features in common with
Pontypridd (HEW 27), including the use of thin stones to form the arch ring; the
severe road gradient; and the narrowing in plan from abutments to mid-span;
but has no opening in the spandrels. Both span and width of bridge are much
less than those of Pontypridd. There is a noticeable tendency of the arch to be
pointed at the crown like the first Ouse Bridge at York. At the present time the
bridge is being affected by mining subsidence.
CEFN COED Y CYMMER
VIADUCT
HEW 171: SO 030 076
During the second half
of the 19th century the network of railways expanded
rapidly in South Wales to handle the vast tonnages of coal being produced. The
difficult terrain forced the construction of numerous viaducts, some with masonry
arches, some with metal spans. Often of great height and curved in plan, they
produced some excellent and sometimes unique examples of bridge
engineering. Many have since been demolished and others are disused, such
as Cefn Coed, a masonry viaduct which carried a part of the Brecon and
Merthyr and London and North Western Joint Railway over the Taf Fawr. It is
770 ft long and 115 ft high with 15 semicircular arches of 39 ft 9 in. and is on a
curve. It was designed by Alexander Sutherland in consultation with Henry
Conybeare and built by Savin & Ward in 1866.
The line was opened
on 1 August 1867 and closed in 1962.
PONTYCAFNAU
HEW 656:SO 038071
This unique cast iron
'bridge of troughs' still spans the River Taff where it was
built in 1793 to carry a tramroad and water supply into the Gyfarthfa ironworks in
Merthyr Tydfil. The designer was the chief works engineer, Watkin George. In
1795 a second bridge, which no longer exists, was cast from the same patterns
to an extension of the tramroad from the works to the bridge, now used by
pedestrians, spans 47 ft. Two substantial A-frames, one on each side of the
deck, have their feet embedded 'n the river walls, with the apex at mid-span. The
frames are held together by rnortice-and- tenon and dovetail joints (George was
a former carpenter) and incorporate sockets which carry transverse members at
mid-span and at the quarter points. These in turn support the deck structure,
which is a closed rectangular box about 2 ft deep and 6 ft 2 in. wide.
Pont y Cafnau undoubtedly
had its influence on other, better known, aqueducts.
In 1794 the Shropshire ironmaster, William Reynolds, sketched the bridge and
in the following year Telford reported that the design and method of construction
of Longdon-upon-Tern Aqueduct, itself a prototype for Pontcysyllte (HEW 112)
had been referred to Reynolds and himself.
RAILWAY BRIDGE AT CWMBACH,
ABERDARE
HEW 1055:SO 024 Oil
This steel truss bridge,
which carries the only remaining railway line in the
Aberdare valley over the Afon Cynon, played an interesting role in the
development of modern design practices and construction techniques.
In the 1960s, the A40
trunk road east of Oxford was bein& widened from single
to dual carriageway, and at Wheatley a bridge was erected in 1961 to carry the
single-track Oxford to Tharne branch over the new carriageway. It was required
to match in general appearance the adjacent rivetted truss bridge over the
existing road.
P. S. A. Berridge was
responsible for the design and chose to develop a
structure which was largely prefabricated by welding, but with the necessary
degree of site assembly carried out by Tor-shear bolts, which acted by applying
a known pressure to the mating surfaces of the joints.
The experience gained
was used in the construction of the much larger trusses,
also designed by Berridge, which, in 1962, replaced I. K. Brunei's tubular
suspension bridge at Chepstow.
Both bridges were fabricated
at the Fairfield works at Chepstow, successors to
Messrs. Finch, who did so much work for Brunei.
In 1973, on closure
of the Thame branch, the bridge at Wheatley was
dismantled and re-assembled near Aberdare. This time the more recently
developed Huck fasteners were used for joint assembly.
ROBERTSTOWN CAST IRON
TRAM BRIDGE, ABERDARE
HEW 371:SN 997 037
This interesting little
bridge is certainly one of the oldest surviving 'railway'
bridges in the world. In 1811 the Aberdare Canal Company completed a
tramway between Hirwaun and the canal head at Cwmbach. The bridge carried
the tramway across the River Cynon between Trecynon and Robertstown.
Four arched and trussed
cast iron beams spring from continuous cast iron
brackets built into the abutments. The width of each truss is only 3 in. and the
depth varies from 1 ft at the centre to over 5 ft at the ends. Seventeen cast iron
plates 9 ft 11 in. wide make up the total length of deck of 36 ft 8 in. The stone
abutments were built with obvious skill.
HENGOED VIADUCT
HEW 804: ST 155 949
The masonry Hengoed,
or Maes-y-Cwmmer viaduct, like the iron viaduct at
Crumlin (HEW 72) was one of the major structures on the Taff Vale extension of
the Newport, Abergavenny and Hereford Railway, and was built in 1857. It has
16 spans of 40 ft semicircular arches and a maximum height of 130 ft. It is built
in rough stone, on a curve, and crosses the A469 (spans three and four), River
Ryhmney (span seven), and a minor road (span eleven).
CRUMLIN VIADUCT
HEW 72: ST 213 986
Of all the many viaducts
in South Wales, perhaps the most interesting and
certainly the most dramatic was that at Crumlin.19'20 It is still worth describing
although it was demolished in 1966. There is a small model in the National
Museum of Wales and traces of the piers can be found on site.
Crumlin Viaduct had
ten spans, divided into two groups, of seven and three, by
a rock knoll. The total length approached 1700 ft. Grossing the valley of the
Ebbw river at a height of 200 ft, the viaduct was built in 1857 by the Newport,
Abergavenny and Hereford Railway for their extension to the Taff Vale. The piers
Newport Transporter
Bridge each consisted of 12 cast iron columns 12 in. dia.
in three rows of four, with an additional raker at each end, covering an area of
about 42 ft by 21 ft. Each column was in eight pieces with wrought iron cross-
bracing to adjacent columns. There were four lines of Warren truss girders, each
of 150 ft span and 15 ft deep, cross-braced by iron plates in 1868 and by steel
from 1930. This was the first large scale multi-span use of this design in wrought
iron.
The viaduct was designed
and built by T. W. Kennard, the partner of James
Warren, who devised the truss configuration which bears his name, and which
was first used for a major bridge at Newark Dyke, on the Great Northern
Railway main line (HEW 1023, SK 801 558).21 The Crumlin columns were cast
at his works and the wrought iron, supplied by Blaenavon Works, was fabricated
at site and hoisted into position.