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April 1, 1868.] THE CIVIL ENGINEER AND ARCHITECT’S JOURNAL. 95 Again, supposing the communication by footboards to be otherwise admissible, we have to take into consideration how far it would be affected by the necessary mixing-up of goods- trucks with passenger-carriages. On all our northern lines especially, perishable goods, such as fish, fruit, meat, etc., are obliged to be sent on with passenger trains, and this to a very large extent; and as these trucks are taken up at the various junctions throughout the kingdom, it would be practically impossible to keep all passenger-carriages in one part of the train, and goods-trucks in another, on account of the ruinous delays it would occasion; they are’necessarily, therefore, mixed up together, and, consequently, goods-trucks, as well as pas senger-carriages, would have to be fittted up with footboards, a condition which would be next to impossible to carry out in practice. There would be no great difficulty in providing the guard with a means of signalling to the engine-driver, from the compartment to which he has been summoned, always supposing we have first got over the difficulty of his getting there whilst the train is in motion; nor are there any obstacles in the way of applying a perfect system of signals between the guard and engine-driver, at all times, or of causing the train, automati cally, to raise an alarm in the act of a portion of it breaking away by accident from the rest. We will pass, therefore, to the act of parliament rendering compulsory the adoption of one and the same system of intercommunication by all the railway companies. The difficulty would be, how far these would willingly submit to having any system imposed upon them, which, after putting them to serious expense, might in the end prove useless. If the government are to select and enforce the use of one parti cular system, clearly they ought to be responsible for its success or failure; the only practical method would be for all the rail way companies, first to agree and decide which was the best and cheapest system, and the government could then enforce its application ; but this would require the whole question to be somewhat further advanced than it is at the present moment. We thus see that the question of providing some passage for the guard along a train in motion is attended with some difficulties, and that if it is to be done at all, it is more easily accomplished (at the expense of a certain amount of privacy) by an interior rather than by an exterior communication. We have already seen that, without such passage, the utility of even the most perfect systems of mere signals between pas sengers and guards would be very seriously impaired ; for, prac tically, a train cannot be stopped immediately on the guard’s receiving a signal. It is true, in the case of a fire, of which the guard may not have been aware, the receiving of a signal would call his attention to it, and he would then have to exercise his judgment, and act in any way he considered best under the circumstances. The following extract, taken from the General Instructions issued by the South Western Railway Company, bears upon this part of the subject:—“When the guards and engine-men shall hear the bell ring they will at once look care fully along each side of the train, and in case any violent oscillation be seen, or a carriage be on fire, or other occurrence of a serious character be observed, the train will be stopped as speedily as possible, and, when stopped, must be protected by signals, as prescribed by the signal book. Should however the guards or engineer fail to observe anything which really necessi tates an immediate stoppage of the train, their duty will be to stop the train at the next station or jnnction, so as to protect the train, when stopped, by the fixed signals.” It should be said that, on the South Western line, a system of electric intercom munication has, for some time, been in operation on certain trains. The difficulty, under our present system, of giving rail way guards the: power of passing along trains in] motion, is at the root of the whole question of intercommunication ; the mere mechanical difficulties in providing an efficient means of signalling an alarm can be got over, but the real question is, what is to be done when the signal has been given ? Practically no system has or can be applied which would enable passengers to communicate verbally, or by any other means, what are the circumstances which have caused the signal. All the other conditions, which we have cited as necessary to be carried out, are comparatively easy of accomplishment. Intercommunication between the guard and driver, by means of a sound-signal, to call attention to sight-signals, or to com municate instructions, directly, by means of an arrangement of sounds, is in very general use on most of our railways. It is commonly effected, the first, by means of a simple cord passing round a wheel in the guard’s van, the other end of which cord is attached to the lever handle of the steam whistle on the engine, and the second, by an electric current made to sound bells at will on the engine and in the van. The same cord or electric wire, in case of any carriage getting off the line, or any portion of the train breaking away from the rest, is violently strained or broken, and, being so extended, may be made to sound the alarm. In another article we propose to turn our attention to the mechanical contrivances which have been tried or proposed in order to effect a perfect intercommunication between the different parts of a railway train while in motion, and we shall then be able to see how far the difficulties of the subject have been overcome, We have now to notice the mechanical contrivances which have been tried or proposed, in order to effect a perfect inter communication between the different parts of a railway train while in motion. The first patented contrivance was for a communication between guards and drivers only, by means of a cord or rope, from a wheel in the guard’s van to the engine whistle (as we have noticed above). The patent was taken out by a Monsieur Petitts, in 1840. From that time down to the end of 1867 about 250 patents have been taken out. We are not going to inflict upon our readers any minute account of these schemes, the larger number of which are as preposterous in idea as they would be impossible in practice. Bnt we shall, perhaps, be able to arrive at some understanding as to the grooves in which the various ideas of inventors have run, by a general classification of the material afforded by the Patent Office. We find we may thus classify all the patented schemes under ten heads. 1st. Cords, coupled, or continuous all along the train, made to actuate signals, such as whistles, bells, gongs, &c., at the extremities, cither by direct pulling of the cords, or the letting: go of spring detents, or clockwork. Some are provided with patent coupling arrangements (one of the best being invented by a young lady), or improved methods of taking up the slack of the cords, necessarily hanging loose between the carriages, to allow for the play of the train. 2nd. Tubes, coupled or continuous all along the train, for the passing of compressed air to blow whistles, or for blowing whistles, when the air is exhausted, or for propelling by a blast of air, wooden or pith balls along the tubes. 3rd. Speaking Tubes, of metal, india rubber, or gutta percha, all along the train, with mouth pieces in each com partment, and with or without whistles, or calling attention and appliances for assisting the voice. 4th. Torsion or other shafts, that is to say, rigid metal rods attached to the carriages which can be made to gear into each other, and so transmit some rotary or horizontal motion along the train to actuate sight or sound signals. 5th. Sound Signals, emanating from each separate carriage, such as whistles, or trumpets, blown by the force of air, com pressed by pumps, revolving fans, &c., driven by the moving axles of the train, or explosive compounds, struck by spring hammers, Jet go by the passenger. Generally at the same time, some exterior sight signal is released, which serves to indicate the compartment whence the alarm has been given. 6th. Sight Signals, only, depending of course, solely on the vigilance of the guard; these consist of flags, semaphore arms, lamps, &c., protruded into prominent positions, on the top or sides of the carriages. 7 th. Means of enabling the guard to pass along the train in motion, either by footboards or trucks, running along the top. or cages, by the sides of the carriages, or by sliding doors of various kinds, permitting a passage throughout the interior of the train. 8th. Reflectors, placed so as to reflect the sides of the train, on mirrors fixed to the guard’s van, or in front of the engine driver. 9th. Electrical systems of signalling by sounding bells. 10th. Windows, or openings of various kinds, between the compartments, together with three or four proposals so de cidedly original in character as to defy any attempted classifi cation. We will now briefly point out some of the disadvantages of greater or less importance, which are inseparably connected with all these systems, Simple cords or ropes through the train, attached to the steam whistle, or to bells on the engine,