Rhondda Tunnel

Construction

During much of the 1800s, the rich coal deposits found in and around the Rhondda were a highly important part of the local economy.^[2] By the 1870s, the sheer volume of coal being extracted was threatening to exceed the capacities of the dominant rail-based carriers of the era, the Taff Vale Railway and Cardiff Docks; reportedly, a typical return journey took two days due to the congestion and inadequate handling. This became a hindrance to waiting customers, particularly the recently opened coal shipping facilities at Swansea, and there was a demand to develop a new railway line to relieve the situation.^[2] Out of the varied proposals emerged the Rhondda & Swansea Bay Railway (R&SBR), which was incorporated on 10 August 1882. The new company set about establishing a shorter export route via the Afan valley; however, it was apparent that the proposed route for the line featured a significant natural barrier in the form of the 1,700 foot-high Mynydd Blaengwyfni hill.^[2]

The R&SBR assigned to engineer Sydney William Yockney the construction of a viable route across this obstacle. Yockney had prior connections to tunnel engineering through his father, Samuel Hansard Yockney, who had acted as engineer and manager during the construction of Box Tunnel on the Great Western Railway and had gone on to work for famed engineer Isambard Kingdom Brunel on a number of other tunnel projects.^[2] The contract for producing the section of the line that included the construction of the Rhondda Tunnel was awarded to Neath-based contractor William Jones, while William Sutcliffe Marsh served as the project's resident engineer. Even before construction started, it was clear that a long tunnel would be needed: as of 2016, the Rhondda Tunnel remains the second longest in Wales at 3,443 yards.^[2]

On 30 May 1885, the first ground was broken on the endeavour; the tunnel was planned to be completed in three years.^[2] However, progress was initially hindered because the purchase of land at the eastern end of the route was delayed; this took 15 months to resolve. Early reports by Yockney to the R&SBR's directors were positive, stating that ground conditions were favourable and that there was relatively little water ingress being encountered.^[2] Reportedly, the miners, who were mainly accessing the site via shafts driven into either end of the approach cuttings and equipped with contemporary compressed air-powered rock-drilling apparatus, were driving a bore into the sandstone at a rate of 240 yards per month. Due to the high levels of ground cover, in excess of 900 feet, the use of conventional intermediate shafts in order to speed construction had been discounted as impractical.^[2]

The tunnel construction workers faced dire conditions, resulting in a number of injuries and deaths, several of these were due to included rock falls and explosions.^[2] By 1887, the tunnel building had slowed to roughly 70 yards per month in some months; according to author Graeme Bickerdike, this was attributed to a shortage of men willing to participate, as well as the discovery of underground springs.^[2] As a result, the company was forced to push back the contractual completion date to 31 July 1889. The two headings met on 16 March 1889 and were found to be perfectly aligned, but the delays led to William Jones being stripped of the contract in favour of Westminster-based Messrs Lucas & Aird in September 1889.^[2]

The new contractor quickly brought 1,600 men on site; to house them, 300 more homes were built on the Rhondda side of the bore.^[2] Around this time, electric lighting was installed to aid their work. Construction soon returned to a satisfactory rate.^[2] On 2 May 1890, the Rhondda Tunnel was officially inspected by Colonel Rich of the Board of Trade; however, Rich said that the tunnel should have been fully lined, and would not authorise its use for passenger traffic until this was done. Accordingly, 759 yards of brick arch were installed over the arched concrete sidewalls; this was done within 54 days, in part due to Lucas & Aird having anticipated such a demand by the inspector.^[2]

Operating life

On 2 July 1890, the Rhondda Tunnel was officially opened.^[2] But the R&SBR failed to purchase adjacent coal seams running both above and below the tunnel which, according to Bickerdike, was common practice to prevent other parties from mining and perhaps damaging the tunnel. Within decades of opening, these seams were exploited and the tunnel began to distort.^[2]

Between 1938 and 1953, around 500 steel ribs were installed along the tunnel's length, to try to resist pressure which was causing noticeable inward movement of the side walls, as well as consequential pushing-up of the crown, particularly towards the tunnel's eastern end.^[2] But it did not work; Bickerdike notes that a settlement of 15 inches was recorded across a 12-year period. More problems were caused by the substantial water penetration from underground springs that had been met during construction, which had weakened and washed out the mortar between bricks in places.^[2] Several lengths of arch were relined as sporadic sections of brickwork became loose and would often fall onto the track. This impacted operations as speed restrictions were soon imposed to guard against the threat posed by a collision with debris.^[2]

A survey of the Rhondda Tunnel in 1967 revealed severe distortion around the middle of the tunnel, close to a natural geological fault.^[2] The rate of deterioration was so severe that the inspecting engineer decided to close the tunnel to traffic on safety grounds. On 26 February 1968, the tunnel was closed, supposedly as a temporary measure, whilst a decision was made on the future of the line.^[2]

In December 1970, the Ministry of Transport announced the formal withdrawal of all passenger services via the Rhondda Tunnel, citing a decline in usage and the provision of a bus service in its official justification for the decision.^[2] The ministry deemed the estimated cost of £90,000 to be prohibitive; but this also conveniently coincided with the Beeching cuts; the two stations either side of the tunnel, (Blaenrhondda and Blaengwynfi), were also closed at the same time. Following a decade of disuse, in 1980, both of the Rhondda Tunnel's portals were covered over and landscaped to prevent unauthorised intrusions, which had reportedly become commonplace in the years since its closure.^[2]