“The cover this week shows an aeroplane engine being prepared for a wind-tunnel test at the Royal Aircraft Establishment at Farnborough, Hants. The tunnel is equipped with a 30-feet fan and is built of steel and reinforced concrete.”
This cover was later used as the colour plate in part 21.
THE Great Western Railway has relied for a long period on the single-expansion 4-6-0 type of locomotive as most suitable for the haulage of its express trains. This policy is the fruit of careful experiments with simple and compound engines having various wheel arrangements.
Experiments were made many years ago by the Great Western Railway with Swindon-built locomotives converted to the 4-4-2 or Atlantic type, which were run concurrently with its contemporary 4-6-0s. In addition, the company bought in 1903 a French compound Atlantic, working on the De Glehn-Du Bousquet system, and in 1905 two similar but larger locomotives were imported from France. In 1908 there was turned out from Swindon works the first Pacific, or 4-6-2 locomotive, to run in Great Britain. This was called The Great Bear. The data obtained front these experiments suggested to the company that neither Atlantics nor Pacifics - at any rate, those of the period - were suitable for its line. The Swindon-built Atlantics were reconverted into 4-6-0s, the French Atlantics were scrapped after some years of service, and the Pacific was converted into a 4-6-0.
Since then the Great Western Railway has built a number of 4-6-0 express and mixed traffic locomotives, all having single expansion. Some of them have two cylinders, others four. Of the four-cylinder 4-6-0s the most powerful are those of the King class - so called because the engines are named after kings. No. 6000, the first of the series, appeared in 1927 and was called King George V. A typical King is No. 6028, King George VI, illustrated below. This locomotive has four cylinders, each 16¼ in diameter by 23 in stroke. The outside cylinders
drive the second pair of driving wheels, and the inside cylinders the leading pair. The driving wheels are of 6 ft 6 in diameter, 2½ in less than that of the Castles, the Great Western 4-6-0s next in order of power to the Kings. The diameter of the bogie wheels is 3 feet. The taper boiler barrel, characteristic of modern Great Western locomotives, has a length of 16 feet. The outside diameter tapers from 6 feet to 5 ft 6¼ in. The total heating surface is 2,514 square feet, including 313 square feet of superheating surface. In conformity with Great Western
practice, the boiler of No. 6028 works with a moderate degree of superheat. The working pressure is 250 lb per square inch - a high figure for British locomotives. The firegrate area is 34.3 square feet. Tractive effort, at 85 per cent boiler pressure, is 40,300 lb.
Among the most productive tin mines in the world are those in the Federated Malay States, where the ore is extracted by many different processes, all of them of great interest. From the time that tin-bearing ore is minded to when the tins are made and the food is packed, the engineer has been responsible for the processes. Tin has always been a much used metal, and for many centuries the tin mines of Cornwall were among the most prosperous in the world. To-day, however, the greater part of the world’s requirements is obtained from the Federated Malay States, where the ore is extracted from the earth by various methods. In this chapter Sidney Howard describes the tin mines of Malaya. A great deal of ore is obtained by the use of mammoth dredges, of which the majority are operated by self-contained steam plants. Another form of mining tin, popular with Chinese miners, is known as gravel pump mining. This method resembles the hydraulicking used for obtaining gold in California. Large excavations, too, are made by open cast mining in which rails are laid and mechanical excavators load the trucks with ore. The ore is treated in Malayan mills and refineries. All these processes are described in this chapter.
Below the streets of London is an amazingly complex system of tunnels which carry thousands of miles of electric cables, gas mains and the like, in addition to the underground rivers which drain the huge area. Of all these subterranean services in London, or in any great city, prhaps he most important are the water supply and the sewerage systems. In this chapter,
C Hamilton Ellis describes how the authorities deal with the important and difficult problem of draining such a city as London. An idea of the immensity of the system can be gathered from the fact that there are more than 2,500 miles of ordinary street sewers and 400 miles of main sewers in London. The larger sewers of to-day may be of brick, concrete or iron, and they may vary in diameter from 4 ft 6 in to 11 ft 4 in, comparable in size to a tube tunnel. This chapter does not, or course, describe the railway tunnels of London, because this is a subject so large that it must be treated in a separate chapter.
“ELECTRIC CABLES ARE CARRIED BENEATH THE River Thames in a tunnel from Deptford Power Station, London, to the north side of the river. The large cables are so heavy that they are made in short lengths and spliced together in position. The jointer is at work splicing the cables in the tunnel. In the London area are over 300,000 miles of underground telephone wires and nearly 4,000,000 miles of underground local wires.”
Building the Hindiya Barrage
“BUILDING THE HINDIYA BARRAGE across the channel into which the River Euphrates was diverted. The barrage has thirty-six openings, each 16 ft 5 in wide. All the piers, built of brickwork, have a width of 5 feet, except for two, which are 11 ft 6 in wide.”
OF the names heading the chapters of engineering history there are few which are duplicated.
It is seldom that father and son both prove worthy of the honour. One such name is that of Brunel. Isambard Kingdom Brunel was the son of Sir Marc Isambard Brunel, the engineer of the first Thames Tunnel (see the chapter beginning on page 341). Sir Marc was a man of great inventive genius, resourceful and indomitable, but he received from his adopted country much less than was his due. With such a father, the boy Isambard, born at Portsmouth (Hants) on April 9, 1806, had fewer difficulties to face in becoming an engineer than had many other pioneers, but that is not to say that he was not the maker of his own reputation. His early education was of the kind then current in Great Britain, save that he spent two years in a mathematical college in Paris, in which he achieved distinction. At the age of seventeen he started practical work in his father’s office.
The Thames Tunnel was begun in 1825 and young Brunel found himself in the thick of the battle against the river overhead. On one occasion, after a break-in had driven out the workers, he returned to the rescue of an old engine attendant who had been left behind; on another occasion he narrowly escaped the death that overtook six of the men in the workings.
The tunnel was formally opened in 1843, but long before that Brunel had been employed on other important matters. In 1836 work was begun on the well-known Clifton Suspension
Bridge, near Bristol. This bridge was built, with a span of 702 ft 3 in and a deck 245 feet above the River Avon, to the designs that Brunel had prepared five years before. He was engaged also on docks and railways in England and on the Continent.
It is, however, as the engineer for the Great Western Railway that most people remember Brunel. The last of his broad gauge track was taken up in 1892, and its disappearance was tacitly accepted in many quarters as an admission of failure. But to the better-informed it is still an open question whether Brunel was not right in his persistent advocacy of the 7-feet gauge
against the now standard gauge of 4 ft 8½ in. The locomotive of to-day is handicapped by the small size of its boiler, and the narrow gauge imposes severe limitations on the size of the firegrate. A larger boiler would have been practicable on the frame of the broad-gauge engine. The broad gauge had, moreover, other advantages likely to be of considerable value to-day. Not least of these advantages was the greater roominess of the coaches. The narrow gauge had, however, too long a start and, in unifying the railway system of the country, it was much
simpler to reduce the broad than to widen the narrow gauge. The change was not made all at once, as much of the Great Western Railway had latterly three rails, making it possible to run
broad-gauge and standard-gauge trains on them. The removal, then, of Brunel’s permanent way does not prove that he was wrong, and his layout of the Great Western Railway is still regarded as a fine piece of work. The great bridge over the River Tamar at Saltash (Cornwall), a compound of the chain suspension and bow suspension principles, remains his chief visible monument. Even when judged by the exacting standards of to-day it is a notable achievement. His fine timber viaducts across the deep valleys of Cornwall also demonstrated up till quite recently his great constructive ability, and in the Box Tunnel, near Bath, on the London-Bristol main line, Brunel confounded those who had predicted that he had undertaken an impossible task.
The early engineers had an immensely harder task than their successors. They had weaker materials to deal with; the ubiquitous steel of to-day did not exist; there were only comparatively primitive tools and apparatus for handling heavy masses; and few data for reference had been accumulated. Brunel was a good example of the pioneer worker, and his
name is also closely associated with the early steamships, in the building of which he led his contemporaries by recognition of the merits of the screw propeller and the iron hull. A wooden vessel, the Archimedes, had been built to demonstrate the screw to the Admiralty. Brunel, having grasped the possibilities of this form of propulsion, changed his designs for the 3,618-
tons steamer Great Britain, then building at Bristol, from paddle to screw propulsion. This vessel was launched in 1843 and had an iron hull without external keel, and a balanced rudder. These were at the time innovations for a sea-going vessel. Encouraged by the success of this
vessel, Brunel, in conjunction with a naval architect, Scott Russell, designed the famous Great Eastern, a vessel 680 feet long, with a tonnage of 18,914 gross. This ship was of iron and was
launched after great difficulties in 1858. It is said that the anxieties connected with the building of the Great Eastern, not due to faults in design, hastened Brunel’s end. At all events, he was taken ill at her engine trials and died shortly afterwards, on September 15, 1859, a
SHORE END of the King George V Graving Dock during construction. At this end of the dock was set up the special plant which washed the gravel excavated from the dock site and mixed the concrete used for building the floor and walls of the dock.
World’s Largest Graving Dock: The Floor of the Dock
THE FLOOR OF THE DOCK is built of concrete 25 feet thick. This slab of concrete, 200 feet wide and 1,200 feet long, serves the double purpose of supporting the weight of the world’s largest liners and of holding down the pressure of artesian water from underneath. At intervals of 200 feet the walls of the dock are vertical buttresses.
A Tin Mine Dredge
THE ENDLESS CHAIN OF BUCKETS in a modern tin mine dredge. The buckets are made of manganese steel and have a capacity of about 16 cubic feet. They dredge to a maximum depth of about 120 feet. The chain of buckets is carried on rollers resting on a steel frame or ladder which is pivoted to the superstructure at the top and suspended at the bottom by cables leading through the sheaves to a winch. Thus the lower end of the chain of buckets can be raised or lowered as required. The men standing on the deck of the pontoon give an indication of the size of the dredge.
Kettle Rapids Bridge
KETTLE RAPIDS BRIDGE is the longest bridge on the eastern section of the Hudson Bay Railway. The bridge, which crossed the lower reaches of the Nelson River, is 3,000 feet long. In winter, work on the bridge had often to be suspended because of severe storms. Machinery and tools often had to be lashed down to prevent them being blown away.
An Inverted Siphon
“AN INVERTED SIPHON is built to carry a sewer under an obstruction such as an underground railway or an open watercourse. This diagram show the usual arrangement of an inverted siphon. From an inspection chamber equipped with a manhole the sewage passes through a sliding gate or penstock into an inclined passage leading to a vertical upflow channel provided with a sump.”
Pneumatic Sewage Ejector
“PNEUMATIC SEWAGE EJECTOR invented by Isaac Shone and designed to raise sewage from low-lying drains to the main sewers. Sewage coming from the inlet fills a chamber until it raises a float which opens a valve admitting air under pressure. This forces the sewage up in the discharge pipe to the main sewer.”
Junction Between Lesser and Main Sewers
“JUNCTION BETWEEN LESSER AND MAIN SEWERS is effected through a penstock and a drop pipe connecting the two. The flow through the drop pipe is controlled by the penstock, which is situated in a spacious inspection chamber. Access to the inspection chamber is given by a manhole at ground level and by a series of steps in the walls. The main sewer is at a lower level than the branch sewer, and another series of steps give access to it from the inspection chamber.”
An enormous feat of engineering was involved by the building of the largest graving dock in the world, at Southampton on a site reclaimed from the sea. Named the King George V Dock, it is large enough to accommodate a vessel of 100,000 tons. One of the most important assets of a seaport is a graving dock which can accommodate the large vessels that call at that port. Southampton is a port of call for the largest liners in the world, and the King George V graving dock at this port is capable of accommodating a vessel of 100,000 tons. The Queen Mary, which sails regularly from Southampton, has a gross tonnage of 80,773, so that Southampton’s great dock will be able to accommodate vessels considerably larger than the Queen Mary if and when they should be built. The site of this great dock, the largest graving dock in the world, was once a mud flat, and the first task confronting the engineers was to reclaim the land from the sea. The whole task of reclaiming the land and building the dock was an engineering feat of immense proportions. The dock is 1,200 feet long, 135 feet wide at the entrance and 59 ft 6 in high. More than one and a quarter million cubic yards of material were removed from the site by mechanical excavators. This chapter by F E Dean describes the building of the huge graving dock and is illustrated with a section in photogravure.
Work in Progress
“WORK IN PROGRESS on the huge basin of the King George V Dock at Southampton. From the site of the dock about 1,258,000 cubic yards of material were removed. The material was composed mainly of gravel which was used in making the concrete walls and floor of the dock.”
Building the King George V Graving Dock
THE CAISSON “CAMBER”, or cavity. of the King George V Graving Dock, at Southampton, was excavated at the eastern side of the dock entrance. The dock is closed by a huge steel caisson. To open the dock the caisson is moved into the camber along steel runways. In the background is the line of the new quay wall and embankment which has reclaimed a considerable area from the sea and has added nearly 7,500 feet to the length of quays at Southampton.
BEHIND AN EARTHEN EMBANKMENT the reclaimed area was pumped dry and the huge graving dock built. When the dock was completed the embankment which covered the entrance to the dock was dredged away and the dock was open to the sea.
Photogravure Supplement - 3
A MINIATURE DOCK, opening off the entrance to the graving dock, was built to receive the caisson gate when the graving dock entrance is open. The caisson is hauled into this dock, or “camber”, by an electrically-driven winch operating massive steel chains.
Hong Fatt Mine
THE LONG INCLINE up which excavated material is hauled to the puddlers on the surface. The photograph shows the Hong Fatt Mine, one of the largest open cast mines in the Federated Malay States. The mine is 3,700 feet long, 1,600 feet wide and nearly 300 feet deep.
Over muskeg and swamp for 500 miles a railroad was built from the prairies of Manitoba to Churchill, on the shores of Hudson Bay, where a grain elevator and other port facilities were provided as a new outlet for the produce of Western Canada. Of recent years the building of the Hudson Bay Railway and the establishment of the port of Churchill on the shores of Hudson Bay have aroused considerable interest. The new outlet for the wealth of the prairie lands of Manitoba has justified the expenditure of £6,000,000. The engineers who forced a way in the little-known regions of the Far North to link Hudson Bay with the prairies of Manitoba endured great hardships. This chapter, by Harold Shepstone, describes the building of this pioneer railroad. The chapter is concluded in part 19. It is the sixth article in the