From the lower flange of a suspended !; runway, made of a single I section, run wheels, from the axles of which the transporter is suspended.
In whatever form energy is produced and distributed to the train it ultimately appears as mechanical energy applied to turn one or more axles against the resistance to their rotation imposed by the weight on the wheels and the motion of the train.
If the energy supplied is distributed between several axles the relation becomes l l 2 3 w 3.
= RV (2) where T 1, T2, T3, &c. are the torques on the axles whose respective angular velocities are wl,w2, W3, &c.
The fundamental condition governing the design of all tractive machinery is that the wheels belonging to the axles to which torque is applied shall roll along the rails without slipping, and exert a tractive force on the train.
If there are several driving-axles in a train, the product Tw must be estimated for each separately; then the sum of the products will be equal to RV.
This perfection of distribution is practically attained in present-day practice by the multiple control system of operating an electric train, where motors are applied to a selected number of axles in the train, all of them being under the perfect control of the driver.
The fundamental difference between the two methods is that while the mechanical energy developed by a steam engine is in the first case applied directly to the driving-axle of the locomotive, in the second case it is transformed into electrical energy, transmitted over relatively long distances, and retransformed into mechanical energy on the driving-axles of the train.
In the first case all the driving is done on one or at most two axles, sufficient tractive force being obtained by coupling these axles when necessary to others carrying heavy loads.
This would be distributed between three coupled axles giving an average of 1.38 tons per axle, though the distribution might not in practice be uniform, a larger proportion of the weight falling on the driving-axle.
It is generally designed as a 4-2-2 engine, but some old types are still running with only three axles, the 2-2-2.
When the service is frequent enough to give a good power factor continuously, the steam locomotive cannot compete with the electric motor for the purpose of quick acceleration, because the motors applied to the axles of a train may for a short time absorb power from the central station to an extent far in excess of anything which a locomotive boiler can supply.
The first railway carriages in England had four wheels with two axles, and this construction is still largely employed, especially for short-distance trains.
Later, when increased length became desirable, six wheels with Passenger g g three axles came into use; vehicles of this kind were carria es.
In both the four-wheeled and the six-wheeled types the axles were free to rise and fall on springs through a limited range, but not to turn with respect to the body of the carriage, though the middle axle of the six-wheeled coach was allowed a certain amount of lateral play.
The current required for it is generated by dynamos driven from the axles of the coaches.
With electricity, power can be applied to as many axles in the train as desired, and so the whole weight of the train, with its load, may be utilized if necessary.
Larger cars are usually dumped by means of rotating or swinging cradles, the car bodies being rigidly attached to the axles or trucks.
The furrow wheels are placed on inclined axles, the plough beam being carried on swing links, operated by a hand lever when it is necessary to raise the plough out of the furrow.
Chromium also, in comparatively small quantities, is taking its place as a constituent of steel axles and tires, and in the manufacture of tool-steel.
The weights of engines and wagons are now greater, and in addition it is recognized that the concentration of the loading at the axles gives rise to greater straining action, especially in short bridges, than the same load uniformly distributed along the span.
In dry seasons this will supply 6000 H.P., and for quite ten months in an ordinary year 14,000 H.P. The plant in 1902 consisted of five turbines, having horizontal axles, and each developing woo H.P. when running at 300 revolutions a minute.
It has a good water-power, and among its manufactures are wagons and carriages, axles, furniture, flour and electric signs.
There are great iron and steel works, producing every kind of heavy goods used by railway and engineering works, such as boiler plates, rails, axles, tubes, bolts and nuts.
As an example of circular shifting may be cited the motion of the coupling rod, by which the parallel and equal cranks upon two or more axles of a locomotive engine are connected and made to rotate simultaneously.
In 1905 Laconia ranked first among the cities of the state in the manufacture of hosiery and knit goods, and the value of these products for the year was 48.4% of the total value of the city's factory product; among its other manufactures are yarn, knitting machines, needles, sashes and blinds, axles, paper boxes, boats, gas and gasolene engines, and freight, passenger and electric cars.
(The architect being at that time also the contractor.) The chapters are -- (1) on various machines, such as scaling-ladders, windmills, &c.; (2) on windlasses, axles, pulleys and cranes for moving heavy weights, such as those used by Chersiphron in building the great temple of Diana at Ephesus, and on the discovery by a shepherd of a quarry of marble required to build the same temple; (3) on dynamics; (4) on machines for drawing water; (5) on wheels for irrigation worked by a river; (6) on raising water by a revolving spiral tube; (7) on the machine of Ctesibius for raising water to a height; (8) on a very complicated water engine, the description of which is not intelligible, though Vitruvius remarks that he has tried to make the matter clear; (9) on machines with wheels to register the distance travelled, either by land or water; (10) on the construction of scorpiones for hurling stones; (11) and (12) on balistae and catapults; (13) on battering rams and other machines for the attack of a fortress; (14) on shields (testudines) to enable soldiers to fill up the enemy's ditches; (15) on other kinds of testudines; (16) on machines for defence, and examples of their use in ancient times.
Wheels creak on their axles as the cogs engage one another and the revolving pulleys whirr with the rapidity of their movement, but a neighboring wheel is as quiet and motionless as though it were prepared to remain so for a hundred years; but the moment comes when the lever catches it and obeying the impulse that wheel begins to creak and joins in the common motion the result and aim of which are beyond its ken.