RAILWAY. 



RAILWAY. 



i U a> efficient M the 6 or 7 feet gauge ; and it U immeasuraMy 

 r, both u regards the formation of the roadway and the con- 

 truotion of the rolling plant It seems that the precUe gauge of 

 4 feet &\ inches was the result of a mere accident ; but u it has been 

 adopted on the majority of railways, it ia now desirable to carry it 

 out on all similar works. The space between the rails is usually made 

 6 feet from edge to edge. 



Acetttoriei of At Roadxay.It is often necessary to pass engines and 

 carriages from one line of rails to another, and this U effected by 

 means of switches or points, and crossings by turn-tables, r t.y 

 traversing platforms. If we suppose, ' in Jig. 13, a series of cases in 



which such changes of direction may be necessary, we may perceive 

 that some contrivance is required to guide the flanges of the wheels in 

 such wise as to cause them to follow the new line of rail they are 

 intended to travel upon. This contrivance consists of two moveable 

 rails (>y. 14) working simultaneously and parallelly upon fixed pivots, 



Fig. U. 



so that the flange of the wheel on one side should bear against one 

 of the rails, and should thus be forced to follow it, whilst the other 

 flange would find an open passage which would allow it to follow the 

 new line of direction given. Many varieties of points and crossings 

 have been introduced from time to time, of which the most concise 

 account U to be found in Perdonnet's ' Traite* EWmentaire ' ; but for 

 our present purposes it may suffice to say that the system now gene- 

 rally adopted is the one known by the name of Wyld's patent, in which 

 the surfaces of the rails in the principal line are not touched, but the 

 tongues of the points are made to pass gradually under the heads of 

 the main rails. On the Great Western line many of the points were 

 originally made as in Jig. 15. The radius of the curves of the best 



Fig. 15. 



point* and crossings is usually made equal to 1650 feet, and care is 

 taken that counterpoises should lie fixed, to keep the main line open ; 

 as far as possible, also, no points should be fixed so as to meet the 

 advancing trains on the main line. At the points of turns out of single 

 lines of railways, and at the junction points of embranchments, signal 

 poets are invariably fixed for the purpose of indicating which line is 

 open, and the radius of curvature is made as large as possible. On the 

 Belgian lines, the embranchments are made near the stations, and some- 

 times the radius of the points does not exceed 1000 feet ; but it is to 

 be observed that these embranchments have no back curves like those 

 of ordinary crossings. It may be as well to add, that where the two 

 rails cross one another, grooves are cut to allow the flanges to pass, and 

 guard-rails are placed to check any tendency of the rails to leave tin 

 road, as shown in fy. 1 3. 



Turn-tables present a marked advantage over points and crossings in 

 this respect, that they allow the carriages, &c., to pass from one lim- t 

 the other in a much smaller space; but the operation itself is performed 



slowly, and must bo repeated for every separate carriage. Turn 

 consist of circular platforms of wood and iron, fixed on a level with 

 ihe rails, and mounted on friction-rollers, so as to turn freely MI...U 

 their central pivots ; four rails are fastened on the upper face, and 

 made to correspond with the positions of the longitudinal and trans- 

 verse rails at each quarter revolution, in such cases as those repre- 

 sented in Jig. 16, wherein, if it were desired to transfer a carriage from 



Fig. 16. 



Tie line <i to the line i, the carriage would be rolled to d ; a quarter 

 revolution of the table is then made, and the carriage is pushed M to 

 e ; a similar quarter revolution of the table e is made, and the carriage 

 could then be advanced in either direction on the line rf. 'I'll.' 

 dimensions of turn-tables depend on the sizes of the carriages to be 

 moved : thus, for goods waggons, an 8-feet table will suffit 

 passenger carriages a 12-feet table is necessary; whilst for locon 

 and tenders coupled together, tables of as much as 36 or even ." 

 diameter have been made. Sometimes the turn-tables of stations arc 

 made to serve a series of converging rails ; and in the engine-houses of 

 some railways a large table is placed in the centre, so as to ser 

 purposes of as many as 16 lines. 



Traversing platforms are used when it is desired simply to pass 

 engines or carriages from one line of rails to another situated parallelly 

 to it. They are exclusively fixed in stations where no through traffic 

 can possibly be admitted ; because they consist of a platform suscep- 

 tible of movement only in a direction transversal to that of the line of 

 rails, and moving on rollers in a deep pit extending the whole length of 

 the lines thus put in communication with one another. 



Water-tanks, water-cranes, pumping-engines, and wells, constitute 

 useful adjuncts of railways, but they hardly require special ii.it in 1 in 

 this article. The signal posts, for both day and night services ; tin- 

 provisions for the establishment of the electric telegraph ; the watch- 

 boxes even for the guardians of the way in particular positions, must 

 also occupy the serious attention of the railway engineer. Local cir- 

 cumstances must, however, so modify the manner of dealing with all 

 these questions of detail, that it would be dangerous to attempt to lay 

 down any absolute principles with respect to them, otherwise than by 

 saying that every convenience should be provided to facilitate the 

 discharge of duties upon which the safety of the public so materially 

 depends. It may be added that, with respect to the service of the water- 

 columns for the supply of tenders, the tendency of modern practice is to 

 make them with reservoirs able to hold about 200 cubic feet of water. 

 and to place those reservoirs immediately over the delivery-pipe, so as 

 to ensure the rapid filling of the tenders ; the reservoirs are them- 

 selves filled during the intervals of the trains. Heating apparatus are 

 also provided for the water-columns, in order to prevent the f i 

 of the water. Good signals are especially required at the ent 

 of long tunnels, and at the points of the turn-outs of single lines of 

 railway, or at embranchments. 



On some lines, or portions of lines, as on the old Birmingham and 

 the Blackwall Railways, upon the goods lines at Liverpool, and upon 

 the line from Liege to the Prussian frontiers, it was thought advisable 

 to substitute fixed machinery for the locomotives employed on the 

 other parts of the line. These machines, in fact, gave motion to end- 

 less ropes, passing over grooved wheels and running from station to 

 station upon friction-rollers, to which ropes the carriages were attached, 

 and were thus hauled along. In almost every case, but those at 

 Liege and at Liverpool, these engines have been abandoned; and 

 indeed, the improvements lately introduced in the details of locomotive 

 engines have rendered their intervention unnecessary ; and it may bo 

 suspected that at Liege, even the fixed engines would have been 

 abandoned, had they not been placed on a line in the direct control of 

 the state. The same description of remark may also be extended to 

 the atmospheric railway, which has been so universally abandoned by 

 engineers, that it may suffice here to refer those who desire to make 

 themselves acquainted with its practical and theoretical defects, to the 

 late Mr. R. Stephenson's report upon the subject. The system thus 

 referred to was tried on the largest scale, both in England and in 

 France ; and in both countries it has signally failed (when compared, 

 economically) with locomotive traction. [ATMOSPHERIC RAILWAY.] 



flotlin;/ Stock. Railway carriages for the conveyance of passengers 

 are usually very capacious, the bodies being made to project over the 

 wheels, which in ordinary lines are made 3 feet, or 8 feet C inches in 

 diameter ; but as the ceutre of gravity of the carriages is kept very 

 low, the oversailing of the frame produces no evil effects. On account 

 of the rapid speed at which the carriages travel, and the violent shocks 

 to which they are occasionally exposed, their frames are necessarily 

 made of great strength ; and every precaution ia taken by the intro- 



