Thomas Codrington

“ The joints are fished in the ordinary way, and are as strong as the rail itself. Cross ties are sometimes used, but when the rail is slightly bedded in the concrete foundation they are dispensed with. The paving is set in cement close against the rail, and is bedded directly or in sand on the base of the rail, upon which there is a bearing of 1^ or 2 inches. Such a tramway will stand steam traction and the heaviest street traffic, but the rail, which is of an expensive section, requires entire renewal when the head is worn out. ”

“ The regularity of the surface of the plains, where they are not cut up by streams, is very remarkable, more so on the ground than would perhaps appear from some of the sections, in which the vertical heights being necessarily greatly exaggerated, every irregularity is magnified to about thirteen times its natural scale.
To the westward of the Avon, the triangular tableland between Christchurch, Wimborne, and Poole is cut off on the north by the Stour valley. ”

“ There is much extra wear, and a tendency to form a rut alongside the rail, arising from ordinary wheels using the tram rail, and unless the surface of the paving is kept to the level of the rail the wheels of carriages are caught by the rail, and damage and accidents are caused. To resist the wear near the rails, chilled cast-iron blocks have been used where the traffic is great. On a macadamized road there is the same tendency to form a rut along the outer edge of the tramway paving, which is to some extent prevented by giving a serrated edge to the paving. ”

“ The main mass of gravel consists of rounded chalk-flints, imbedded in sand and distinctly stratified in layers of pebbles of assorted sizes, dipping slightly northward. The flints, though well rounded, have not the finish of the pebbles in tertiary pebble-beds, and the structure shows it to be a beach-deposit. Seams of pure sand overlie bands of pebbles as large as oranges, and layers of pebbles stained a dark red are succeeded sharply by bands of white pebbles. ”

“ It is a great advantage to the ordinary traffic to have the cars moving always in the same direction on the same line of rails.
Points and crossings.For horse traction fixed points of chilled cast-iron or steel are sufficient, as the driver can turn his horses and direct the car on to either line of rails. When mechanical power is used, drop points or movable points are required. In the former the groove leading into the road to be taken is of the full depth, and the other groove shallow, so that the engine and cars naturally take the former. ”

“ The nature of the geological formation appears to have had no part in influencing the destruction or the preservation of the surface. Barton Clay, Bagshot Sand, and Headon Marls alike underlie the gravel of the New-Forest tableland, and have alike been removed over the area drained by the tributaries of the Boldre river, of which Lyndhurst is the centre. The gravel covering itself is probably the protective agent, and it may have been thinner or more loamy where the old surface has been destroyed. ”

“ No carriage used on a tramway must extend more than 11 inches beyond the outer edge of the wheels, and there must be a space of at least 15 inches between the sides of the widest carriages or engines to be used, when passing one another. A width of not less than 3 feet 2 inches between double lines and at passing places is thus necessary, and a double line of tramway, leaving 9 feet 6 inches space on each side, requires a street at least 32 feet 6 inches wide between the footways. ”

“ Northward of the escarpment the general surface of the country is 80 or 100 feet lower, much intersected by the tributary streams of the Beaulieu river, and generally covered by a wash of gravelly loam; but detached gravel-topped hills rise in the lower ground to levels corresponding to the plains, and are evidences of the former extension of the tableland beyond its present northern edge. ”

“ Steam traction.The application of steam as a motive power on street tramways is attended with special difficulties, arising from the conditions under which the engines have to work. A tramway engine must be able to draw its load up steep gradients, demanding perhaps seven or eight times the power required on a level, and it must have the necessary adhesion without being too heavy for the permanent way. It must be capable of traversing sharp curves, of going backwards or forwards with safety, and of stopping and starting quickly. ”

“ In a section in a brick-yard to the east of Lymington the red gravel seems to have been cut away before the white was deposited on its flank. In the chines or bunnies to the west of Bournemouth there are sections at right angles to the coast showing the reel gravel with brick-earth over it, ending against a slope of Bagshot sand on the land side and thinning out towards the sea, so that the white gravel which overlies both overlaps the brick-earth, and rests directly on the red gravel, reduced to less than half its thickness in the sea face of the cliff. ”

“ Passing places.A single line of tramway must have passing places for the cars, consisting of pieces of double line of length sufficient to hold two cars at least, with connecting curves and the necessary points and crossings. Where steam or other mechanical power is to be used the passing loops should be at least 200 feet in length. There is inevitable delay and interference with the street traffic at passing places, and where cars are to be run at frequent intervals it is better to lay down a double line if the street is wide enough. ”

“ The peat-bed does not much exceed a foot in thickness; it is described by Mr. Godwin-Austen, who examined it with Professor E. Forbes, as having the usual characteristics of accumulations of vegetable matter in damp situations, and containing the remains of large trees, hazel-nuts, and beetles [25] . The top of the cliff where the peat-beds are is less than 25 feet above the mean sea-level, and the gravel is much more clayey than the pebble-gravel proper, and confused in the bedding. ”

“ In a combined engine and car the weight of the car and passengers is utilized for adhesion of the driving wheels, and this is conveniently effected in Rowan's car, in which there are two four-wheel bogies, the leading one carrying the engine and boiler, and half the body of the car and passengers. The engine can be detached from the car for repair and another engine can be substituted in a few minutes. Economy of rolling stock, and the advantage of being able to use cars intended for horses, are in favour of independent engines. ”

“ The raised shingle of the Foreland, the marine gravel of the south of Sussex, and the beach-deposits with sea shells at Avisford and Waterbeach are evidences that at a time geologically recent the land stood 80 or 100 feet lower. Flint implements, however, are found imbedded in gravel 120 feet above the sea on the Bournemouth cliffs, and 150 feet above the sea on Southampton Common; and an hypothesis which assumes that man existed when gravels, now 120 and 150 feet above the sea, were forming at or below the sea-level may be on that account alone considered as untenable. ”

“ The system has advantages on double lines with few and easy curves when the gradients are long and steep, and it can be employed on gradients too steep for steam traction. On level lines it is doubtful if it could compete in economy with steam, or even with horse traction, unless with a very frequent service of cars, though then it presents the advantages of being comparatively quiet, and free from smoke and steam, and of admitting a frequent service of cars with little extra cost. ”

“ Denudation of the surface by subaerial action, and of the coast by the sea, must have gone on pari passu with upheaval ever since the high plains were first raised above the sea-level. As the land gradually rose, the effect would have been to contract the inlet and bring it into the condition of an estuary branching into the Solent and Southampton Water. Of these, the latter remains an estuary, while the Solent has become an arm of the sea by the severance of the Isle of Wight from the mainland. ”

“ Smaller cars to carry 20 or 14 persons inside, drawn by one horse, are useful to run at short intervals when the traffic is not great, a frequent service of cars being a great element of success. The car wheels are usually of steel or chilled iron, with a flange half an inch deep, and are fitted with powerful brakes. The axles are about 6 feet apart, giving a short wheel-base to enable the cars to pass sharp curves, but with the disadvantage of overhanging ends. ”

“ The main mass appears to fill up an old channel cut through the shingle, and its highest part could hardly have been deposited much above the level of the sea, which, as the shingle shows, must have been near. A rise of land to the extent of 70 or 80 feet appears, therefore, to have taken place since the deposition of the brick-earth in which the flint implement was imbedded. The peat-beds, and the gravel and brick-earth over them, must have been formed at or above their present level and subsequent to the upheaval. ”

“ In one form of spring point one groove is filled up by a tongue which is pressed down by wheels passing out of a loop, but which forms the side of the groove for wheels running the opposite direction. A spring point of steel, which is forced aside by the flange of the wheel passing out, and shuts close again by its own elasticity, is also successfully used. A movable point on one side of the way is sufficient. ”

“ But if the great height attained by the gravel-covered plains is evidence of an antiquity far greater than that of the Milford Hill, and other high-level valley-gravels, the uniform surface of the tableland points to a continuance of similar conditions from the time of deposit of the highest gravels down to that of the gravel containing flint implements at Bournemouth, Lymington, Hill Head, &c. ”

“ The speed of the cable, which is gene rally 6 to 8 miles an hour, is thus imparted to the car gradually and without jerk. The arrangements for passing the pulleys, for changing the dummy and cars from one line to the other at the end of the road, for keeping the cable uniformly taut, and for crossings and junctions with other lines are of considerable ingenuity. When the cars are cast off from the cable they must be stopped by hand brakes, which on steep gradients especially must be of great power. ”

“ The physical features of the country, and its superficial deposits, are so closely connected that they must be considered together. The New Forest, and the neighbouring country between Poole and Southampton Water, is characterized by high level plains, very generally covered with gravel or brick-earth. ”

“ There is a considerable loss of heat during the expansion of the air which is attended with a serious loss of pressure, and in Mékarski's system, which has been in use for the propulsion of tramcars at Nantes for seven years, the loss of pressure is considerably lessened by heating the air during expansion. The air, at a pressure of 426 lb per square inch, is stored in cylindrical reservoirs beneath the car, and before use is passed through a vessel three quarters full of water heated to 300° F., by which it is heated and mixed with steam. ”

“ From the coast to the escarpment the ground has a uniform inclination of about 20 feet per mile, or one-fifth of a degree with the horizon. The surface is generally covered with gravel, which appears to thicken as the ground drops towards the valleys; the sides of the valleys are free from gravel, and the bottoms contain a gravel much mixed with locally derived clay and marl, and distinct from that covering the plains. ”