The principal lines branching off from the Great Western, and since incorporated with it, are, on the south, the Berks and Hants, from Reading to Basingstoke and Hungerford; and the Wilts and Somerset, to Weymouth and Salisbury. On the north-west is the Cheltenham and Great Western Union Railway, from Swindon to Cheltenham and Gloucester. This line passes through the Cotswold Hills at Sapperton by a tunnel 1⅜ mile in length. The Gloucester and Dean Forest Railway runs from Gloucester to Grange Court, and thence to Ross and Hereford.
The South Wales Railway, which extends from Grange Court to Milford Haven, contains a tunnel at Swansea ⅓ mile long, and some of Mr. Brunel’s most important works, including the Chepstow bridge and several other bridges of considerable size, and the viaducts at Landore and Newport. There are also on this line four opening bridges across navigable channels. The works at the termination of the line at Neyland, in Milford Haven, are described in Chapter XIV. Mr. Brunel considered that Milford Haven, with its excellent harbour, which can be entered at all times of tide by the largest vessels, would probably become a great port for ocean steamers, and especially for the ‘Great Eastern’ and ships of her class.
There are also in South Wales the following railways: the Taff Vale, the Vale of Neath, the Llynvi Valley, and the South Wales Mineral. The Taff Vale, a line from Cardiff to Merthyr, was opened on the narrow gauge in 1841.[46] On this railway is the lofty masonry viaduct at Quaker’s Yard.
On the Vale of Neath Railway, from Neath to Aberdare and Merthyr, there is a tunnel, near Merthyr, 1¼ mile long, and 650 feet below the summit of the hill.
Full advantage is taken on this railway of the facilities which the broad gauge offers for heavy traffic. The line has long steep gradients, and the locomotives used on it, of the class known as tank engines, are of great power. One of these gradients is 4½ miles long, with an inclination of 1 in 50. Large quantities of coal are brought down by this railway to the Swansea and Briton Ferry Docks. The coal of South Wales is of a friable nature, and, in order to avoid the breakage consequent on the ordinary mode of shipping coal, by tipping it down a shoot, Mr. Brunel introduced on a large scale the use of trucks carrying four iron boxes, each box about 4 feet 8 inches cube, and containing two and a half tons of coal. At the docks machinery is provided by which each box is lowered down into the hold of the ship, and the under side being allowed to open, the coal is deposited at once on the bottom of the vessel.
The Llynvi Valley Railway is a short line, leading from the South Wales Railway at Bridgend into the coal and iron districts.
The South Wales Mineral Railway is another line of the same class. It passes through a very heavy country, and has on it a self-acting incline of 1 in 9, ¾ mile long, worked by a rope, and a tunnel ⅝ mile long, and 470 feet below the surface.
In connection with the South Wales district is the Bristol and South Wales Union Railway, a line running from Bristol to the banks of the Severn, across which the traffic is carried by a steamer to a short branch from the South Wales Railway on the other side. This railway had been for a long time contemplated, and Mr. Brunel devoted much time to a careful investigation of the Severn in order to determine the most suitable point for the crossing. He decided that the best place would be at what is known as the New Passage. The arrangements had to be made in accordance with the requirements of the Admiralty. Trains run to the end of timber piers extending into deep water, and there are staircases and lifts leading to pontoons, alongside which a steamer can come at all times of tide. The tide at this part of the Severn rises 46 feet.
The three railways last mentioned were not completed during Mr. Brunel’s lifetime.
The Bristol and Gloucester Railway, on which is the tunnel at Wickwar, ¾ mile long, was opened in 1844, and passed into the hands of the Midland Company in 1846.