When crossing a desert camels are expected to carry their loads 25 m.
The substitution of steel for iron as the material for rails which made possible the axle loads and the speeds of Lto-day, and, by reducing the cost of maintenance, contributed enormously to the economic efficiency of railways, was one of the most important events in the history of railways, and a scarcely less important element of progressive economy has been the continued improvement of the steel rail in stiffness of section and in toughness and hardness of material.
It may happen that from a large station sufficient traffic may be consigned to certain other large stations to enable full train-loads to be made up daily, or several times a day, and despatched direct to their destinations.
It is used to a limited extent for mountain-grade goods traffic, and has the advantage over the " Consolidation " or eight-coupled type of lighter axle loads for a given tractive capacity.
For a simple two-cylinder engine, and cylinder volume is slightly increased with the necessary accompaniment of heavier loads on the coupled wheels to give the necessary adhesion.
On the other hand, where, as in America, the great volume of freight is raw material and crude food-stuffs, and the distances are great, a low charge per unit of transportation is more important than any consideration such as quickness of delivery; therefore full car-loads of freight are massed into enormous trains, which run unbroken for distances of perhaps 1000 m.
The pair spent the balance of the morning emptying the washing machine and dryer, only to fill them with never-ending loads, while in between clearing dishes, brewing more coffee, and playing the jovial innkeepers.
An hour; and quick merchandise trains with limited loads of 300 tons make 35 to 40 m.
An hour, may weigh up to about 4000 tons, and loads of 2000 tons are common.
The orders actually granted have allowed 50 lb, 56 lb, 60 lb and 70 lb rails, with corresponding axle loads of 10, 12, 14 and 16 tons.
In 1898, at Birmingham, a prize of £ioo was given for a self-moving vehicle for light loads, ioo and 50 for self-moving vehicles for heavy loads, and fio for safety feeder to chaff-cutter, in accordance with the Chaffcutting Machines (Accidents) Act 1897.
On arriving in Paris, Deane at once opened negotiations with Vergennes and Beaumarchais, securing through the latter the shipment of many vessel loads of arms and munitions of war to America.
The peculiar two-wheeled carts of the country, carrying enormous loads of 4 to 6 tons, destroy even the finest road.
Merely has the effect of diminishing the maximum elongation and hastening the contraction; with the two greatest loads used in the experiment there was indeed no preliminary extension at all.'
Finally, experiments were made to ascertain the effect of ' The loads were successively applied in decreasing order of magnitude.
[[[Stress And Magnetization]] magnetized under very heavy loads, the wire was indeed found to undergo slight contraction.
The Villari critical point for aegiven sample of iron is reached with a smaller magnetizing force when the stretching load is great than when it is small; the reversal also occurs with smaller loads and with weaker fields when the iron is soft than when it is hard.
There is excellent fishing for salmon and trout, and in summer coaches leave their daily loads of tourists here.
To Ares they make a heap of faggots three stades square, with three sides steep and one inclined, and bring to it a hundred and fifty fresh loads of faggots every year.
Ruth put one on before going out of doors, and its folds could be used for carrying small loads (Ruth iii.
Deep were then sunk, and the chalk taken from horizontal tunnels was brought to the surface and spread on the land at the rate of about 60 loads per acre.
In some cases as little as 40 loads per acre have been used with benefit, in others 180 loads have not been too much.
Great care is necessary to prevent the heaps from becoming too hot, in which case the clay becomes baked into hard lumps of brick-like material which cannot be broken up. With careful management, however, the clay dries and bakes, becoming slowly converted into lumps which readily crumble into a fine powder, in which state it is spread over and worked into the land at the rate of 40 loads per acre.
Regulations were now stricti enforced, fixing the number of horses and carriers available at eac station, the loads to be carried by them and their charges, as well as the transport services that each feudal chief was entitled to demand and the fees he had to pay in return.
Steam at high pressure exhausting into the atmosphere is still commonly used, but the great power required for raising heavy loads from deep pits at high speeds has brought the question of fuel economy into prominence, and more economical types of the two-cylinder tandem compound class with high initial steam pressure, superheating and condensing, have come in to some extent where the amount of work to be done is sufficient to justify their high initial cost.
At starting, when the full load is to be lifted, the balance chain uncoils, and continues to do so until the desired equilibrium between the working loads is attained, when it is coiled up again in the reverse direction, to be again given out on the return trip.
P and p may be measured directly by leading the belt round two freely hanging guide pulleys, one in the tight, the other in the slack part of the belt, and adjusting loads on them until a stable condition of running is obtained.
Whatever type of bridge is adopted, the engineer has to ascertain the loads to be carried, and to proportion the parts so that the stresses due to the loads do not exceed limits found by experience to be safe.
As railway loads increased and greater spans were demanded, the Howe truss was stiffened by timber arches on each side of each girder.
This bridge has now been replaced by a stronger bridge to carry the greater loads imposed by modern traffic. Fig.
The bridge is a deck bridge, the railway being carried on top. The transfer of the loads to the ends of the bridge by ..
In manufacturing districts and near large towns loads of 30 tons may come on road bridges, and county and borough authorities insist on provision being made for such loads.
In Switzerland roads are divided into three classes according to their importance, and the following loads are prescribed, the designer having to provide sufficient strength either for a uniformly distributed crowd, or for a heavy wagon anywhere on the roadway: - In England still larger loads are now provided for.
The following are some of the results Large as these loads are on short spans, they are not more than must often be provided for.
36 gives the loads per axle and the distribution of loads in some exceptionally heavy modern British locomotives.
I In Austria the official regulations require that railway bridges shall be designed for at least the following live loads per foot run and per track: It would be simpler and more convenient in designing short bridges if, instead of assuming an equivalent uniform rolling load, agreement could be come to as to a typical heavy locomotive which would produce stresses as great as any existing locomotive on each class of railway.
Bridges would then be designed for these selected loads, and the process would be safer in dealing with flooring girders and shearing forces than the assumption of a uniform load.
Waddell (De Pontibus, New York, 1898) proposes to arrange railways in seven classes, according to the live loads which may be expected from the character of their traffic, and to construct bridges in accordance with this classification.
Run for spans ll, l 2, and live loads p' per ft.
37 represent a beam with any system of loads W1, W2, ..
The total shear at a b is S = R-E(W1+W2 ...) where the summation extends to all the loads to the left of the section.
If the loads on the right of the section are considered the expressions are similar and give the same results.
Greatest Shear when concentrated Loads travel over the Bridge.
Beyond C, the shear at C will probably be greatest when W2 is at C. Let R be the resultant of the loads on the bridge when W 1 is at C. Then the reaction at B and shear at C is Rn/l.
Next let the loads advance a distance a so that W2 comes to C. Then the shear at C is R(n+a)/l - WI, plus any reaction d at B, due to any additional load which has come on the girder during the movement.
46) be the section at which the greatest shear is required, and let the loads advance from the left till W I is at C. If R is the resultant of the loads then on the girder, the reaction at B and shear at C is Rn/l.
In that case the loads on either side of C are proportional to m and l - m.
Machines used for lifting only are not called cranes, but winches, lifts or hoists, while the term elevator or conveyor is commonly given to appliances which continuously, not in separate loads, move materials like grain or coal in a vertical, horizontal or diagonal direction.
It is at once evident that hand power is only suitable for cranes of moderate power, or in cases where heavy loads have to be lifted only very occasionally.
Sometimes, especially in the case of overhead travelling cranes for very heavy loads, the chain is a special pitch chain, formed of flat links pinned together, and the barrel is reduced to a wheel provided with teeth, or " sprockets," which engage in the links.
This classification is based partly upon special conditions of service, which make some articles more economical to carry than others (with particular reference to the question whether the goods are offered to the companies in car-loads or in small parcels), but chiefly with regard to the commercial value of the article, and its consequent ability to bear a high charge or a low one.
In cases where the route of a line runs across a river or other piece of water so wide that the construction of a bridge is either impossible or would be more costly than is warranted by the volume of traffic, the expedient is sometimes adopted of carrying the wagons and carriages across bodily with their loads on train ferries, so as to avoid the inconvenience and delay of transshipment.
The clay is dug from the land or from ditches or pits and placed in heaps of 60 to ioo loads each, with faggot wood, refuse coals or other fuel.