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An important point will be here observ- The Paliamentary Report states, that “in ed,—that a considerable saving in the cost the cost of the maintenance of way, there of working is effected by the very means would be a difference in favor of the atmoswhich the public advantage requires-pheric principle. namely, by despatching trains as speedily as An objection has been raised to the atpossible. Their weight is consequently mospheric system, on the ground of the exdiminished, and the piston, having less to pense of the stationary steam-engines and draw, may be proportionably smaller in di- establishments, and the liability to accident. ameter. This reduces the cost of the pipe This is replied to by Mr. Samuda as fol(which is the chief item in the first outlay lows :of construction) in nearly the same proportion as the speed is increased, and as the
“The objection as to the complexity and outrapid succession of trains is effected. In lay attendant on a number of fixed engines, short, the economy of working and the ad- may perhaps be better answered by taking a
review of the number and expense of these vantage to the public are here identical. engines and the duty they are required to per
Upon this subject we will only observe, form. On a line 30 miles long, supposing the that a consideration next in importance to average distance between the engines to be 3 that of security, is that of velocity-the miles, there would be 10 engines and air-pumps power obtained by so much greater speed
with their engine-houses; and if the railroad in carriage—and the manifold results which day over the whole distance (considerably
were appointed for transporting 5000 tons per are connected, directly and indirectly, with more than double the amount carried daily on this advantage. To these results we can any railroad in England), the expense of one only draw the reader's attention in a gener- of these stationary engine establishments al way: the value to the Government of a would cost complete £4,200, which, multiplied double rate of speed (independently of a by 10, will give £42,000—total cost on the reduced rate of carriage) is incalculable, whole line. But it is a fact which probably for the transmission of despatches, troops, this expense as a drawback to the atmospheric
must have escaped the notice of those urging etc., but above all for the service of the system, if they were ever acquainted with it, Post Office. We may imagine, but cannot that to perforin a traffic of only 1700 tons per estimate, the vast effect on the revenue and day, upwards of one locomotive engine per business of the Post Office, which must ac- milé is necessary; and as each locomotive crue from the following advantages :-as
costs £1500, the total capital required for loquick a succession of trains as might be comotive power on a railroad 30 miles in length
would be £45,000; in first cost, therefore, there desired,-a speed of transmission more than would be a saving of £3000'in favor of the double the present,-a large reduction of stationary power ; but this is far from being the the expenses of carriage, -besides opening most important saving. Every mill-owner in the possibility of employing railways in Lancashire and Yorkshire, and any person lines where they are now wholly inpracti- connected with mining operations, will readily cable. Without considering the really most admit that this outlay being once incurred for important gain to the nation—of the new his mine, and his engine being once fixed on
a steam-engine to drive his machinery or drain facilities of correspondence-we limit our terra firma, its deterioration, uncertainty of remark to the effects on the Post Office action, or annual expense of maintenance, is revenue.
not a source of annoyance or anxiety to him. Another source of economy in working Five per cent. per annum on the cost will on the atmospheric system is, that the pow- more than cover all repairs necessary to be er expended may be exactly regulated ac- performed to it, and all oil, hemp, and tallow cording to the power required. M. Mallet used in working it. It is the exception, and remarks on this point :
not the rule, if a stationary engine once fixed,
meet with a derangement to render a stoppage “Whatever be the load of the trains, the necessary. Rouen Railway Company pay 16. 10 per kil- The annual expenses will be for repairs at 5 omètre for locomotive power; whilst on the
per cent. on £42,000
£2100 atmospheric system the action of the engines For coal for these engines (when transmight be diminished, and the power propor
porting 2000 tons per day), 6420
6120 tioned to the resistance, by making no more
tons per year, at 20s. per ton
1800 rarefaction than necessary. It would be pos
Wages to engine-men and stokers sible, for instance, to use on ordinary occasions an exhaustion of twelve or thirteen inches ;
£10,320 this could easily be obtained in two minutes. “ The Liverpool and Manchester Railway Thus, at each trip, three minutes' work of the is 30 miles long, and is the only railway that engines would be saved."-Page 52. transports as much as 1700 tons per day over
its whole distance; and the annual expense of than any argument, however strong. In the its locomotive department, including coke, is whole of our workings, the column of mercury about £50,000 a year. Need we make any has never varied in height more than two further comment, when the annual expense of inches on the same day, and as it requires power for the atmospheric system is £10,320, eight times the number of minutes to destroy and for performing the same traffic on the the vacuum in the pipe, when the engine is at locomotive system upwards of £50,000 is found rest, than it takes to raise it when in action, it necessary ? Great as the pecuniary advanta- follows that one-eighth only of the power (two ges have been shown to be, we must not horses) is all that is employed to overcome forget to correct the third objection; viz., the leakage. Perhaps the necessity of stopping erroneous opinion that the system is faulty be- the traffic of a line in the event of an accident, cause an accident occurring at one of ihese until the damage is replaced or the obstacle stations would interrupt the traffic on the cleared away, should be regarded upon all whole line. Primâ facie, this argument is railways as a peculiar advantage: by this correct, but we have already shown how necessity all chance of “running into" is small the chance of accident is to a stationary avoided; and where stationary power is emsteam-engine........ To make assurance doubly ployed the difficulties of communication which sure, a pair of engines and a pair of air pumps, a locomotive line has to contend with are overeach of half the requisite power, may be fixed come. By means of an electric telegraph, at each station: should any thing cause one every engine-station along 100 miles of road engine and pump to stop, the traffic would not may be communicated with in half a minute, be interrupted; the only delay would be the and thus the traffic may be suspended and retardation of the train while passing over resumed at pleasure."- Page 17. that section of pipe where only half the power was in action; and, until the cause of the
M. Mallet has examined this objection stoppage were removed, the trains would be in the following passage :some five or six minutes more than usual performing the journey.- Page 17.
“It has been said, should any accident occur
on your single way, the traffic is all stopped ; We must notice one more objection of a whereas with the two lines of a locomotive serious nature, connected with the em
road, if any thing happens to one you have ployment of a single line of way,-viz. that validity of this objection, neither will I destroy
the other remaining. I will not dispute the an accident occurring at one of the sta- it; bui I can greatly lessen it in stating that tions, or any where along the pipe, may very many of the accidents which happen on interrupt the traffic on the whole line. the locomotive lines, become an impossibility Upon this point Mr. Samuda remarks :- upon the atmospheric. No collision, no prob
able running off the rails: from whence then “ The next objection we have to meet is the will accidents arise ? From evil disposed interruption to the traffic from some derange-persons injuring the road? In that case, the ment in the pipe. This comprehends, 1st, an lines of locomotives are as open to their accident to the pipe itself; and, 2nd, from the attacks as the atmospheric, and they might as composition not being effectually sealed.-- An well injure two lines as one. I see not any accident to the pipe can only occur from break- chance of stoppage, except from the breaking age, and, unlese designedly perpetrated, could of an axle or a wheel, and these are mishaps never happen at all. But for the sake of ar- which occur but seldom; besides which, when gument, we will suppose a pipe has been they do, the road could speedily be cleared broken—no matter how; the time of removing of one carriage rendered unfit for service. I it and replacing it with another would be con- will not for a moment deny that there may be siderably less than the time now necessary to occasions of interruption of the transits; so clear off the fragments of a broken engine and there are also upon the locomotive lines, in train after a collision; and supposing a length spite of their two lines of way.” of valve to require replacing, it could be done in less time than replacing a rail when torn up 4. In the last place we have to consider by an engine running off the line. If, instead the safety afforded by the atmospheric sysof one, there were one hundred places along tem, as compared with other locomotive the pipe where the heater had imperfectly
This is a subject of such paraperformed its functions, the admission of aimospheric air through the composition in these mount importance, that, were any one places would only reduce the column of mer- system proved to afford increased security, cury a few inches: no stoppage or interrup-purchased even by increased cost of contion of the traffic could possibly occur from struction and working, a proper regard to this cause; and by comparing the quantity of public safety of life and limb ought to preair pumped out at each stroke of the with the quantity that will leak in at each im. ponderate over pecuniary motives. When perfectly sealed spot, any such erroneous idea however, on the contrary, an invention will be removed. Perhaps on this head an offers the means of reducing the expenses appeal to experience will be more satisfactory of travelling, and at the same time of obJULY, 1844.
viating the possibility of accident, such a may well be regarded as immovable, from benefit to mankind ought at least to be met its own weight and the strength with which it with every attention and encouragement is fastened down, cannot run off the rail. If any one feature characterizes the prin- other, would have even more difficulty in get
Those which follow it, and are linked to each ciple of the atmospheric railway, it is the ring off the rails. But on a railroad, whilst very element of safety which lies in its the guiding carriage maintains its way, it is of construction and in the mode of its work- little consequence it one of those behind misses ing. On this point we shall first quote the the rail; ils wheels may plough up the soil opinion of M. Teisserenc:
beside the track, but as it cannot get away no
danger is to apprehended, and the worst that “ Au point de vue de la Sécurité.—Il est can happen will be a check in the speed. This facile de montrer que le système atmosphé- is an important result for the construction of rique remédie à toutes les causes principales roads upon the atmospheric system. Curves, d'accident sur les chemins-de-fer en usage also, which on the locomotive system may not aujourd'hui. Quelles sont, en effet, ces causes: be made less than 800m radius, may by this les collisions entre les trains, la sortie de la system be taken much sharper. I do not voie, la rupture des essieux des locomotives, think that it is wise to reduce them as far as les éboulements dans les grandes tranchées, those of the road of Kingstown to Dalkey; les incendies. Avec l'appareil atmosphérique, but I look upon radii of 300m to 400m as quite pas
de collisions, pas d'incendies, pas de rup- possible."— Page 28. ture d'essieu ; la voie modelée sur le niveau naturel du sol ne nécessite pas de grands
This point is of such singular impormouvements de terre ; le train tenu par un point fixe ne peut guère quitter les rails." -- tance to the public, that we deem it desiraPage 117.
ble to compare the opinions of all those
engineers who have examined and reported Mr. Samuda remarks upon this subject upon the merits of the system, as it is esas follows:
sential that the fullest satisfaction should
be afforded. We shall further quote a “ Beside these advantages, this system pos- passage from Mr. Berginos pamphlet, in sesses others of still more importance to the which he notices a remark made in the public. No collision between trains can take place ; for as the power cannot be applied to Parliamentary Report,—that it is a great more than one piston at a time in the same element of safety for the source of power section of pipe, the trains must ever be the to be present with the train. length of a section apart from each other; and it from any cause a train should be stop
"There remains but one other matter to ped in the middle of a section, the train which which I think it necessary to advert; but that follows it will be obliged to stop also at the one is, in my judgment, of such paramount entrance of the pipe, as there will be no power importance, that, more than any other, it charto propel it until the first train is out. It is acterizes the atmospheric system ; I mean the also impossible for two trains to run in oppo- safety of the passengers; not merely relatively site directions on the same line, as the power to other modes of transit, but the highest alis only applied at one end of each section. A tainable degree of absolute safety..... Now train cannot get off the rail, as the leading what the locomotive system is in point of carriage is firmly attached to ihe piston, which safety to the older modes of travelling, I travels in the pipe between the rails; and the believe the atmospheric to be to the locomotive: luggage and carriages cannot be burnt, as no in a word, as free from hazard as it is possible engines travel with the trains.”
for any human contrivance to be. What ele
ments of danger are there ?-collision is imThe opinion given by M. Mallet fully possible, all recognized causes of fracture of confirms this statement. “ Firstly," he parts are almost altogether absent.....In speaksays, “this system, from not employing ing on this subject, the Reporters say, On locomotives, is exempt from all the dan- railways, it is a great element of safely that gers to which accidents to them expose us. and may be almost instantly turned off if any
the source of power is present with the train, ........ In the second place, the risk of colli- necessity shows itself for the stopping::--The sion entirely vanishes, and perfect security presence of the engine, it is too well known, may be enjoyed on that head, two trains has not always proved a source of safety, as never being able to run in the same pipe at no inconsiderable portion of the very worst of once." Again he says:
railway casualties have been solely occasioned
The latter part of the sentence is genUpon an atmospheric railroad there is no erally true; but in this respect there is no possibility of running off the rails; or at least
, difference between the locomotive and the If one carriage gets off the rails 'no accident atmospheric systems; or if there be, it is in can result from it. First, the leading carriage, my opinion in favor of the latter, inasmuch firmly and closely attached to a pipe, which as the means of turning off the power are still
more certain; the regulator or steam-cock of engine, unattended by any of its dangers, a locomotive-engine may stick fast, so that but others in addition. We may observe the engineman cannot move it; this I have that the weight of the engine being dismore than once known to be the case. But there are abundance of contrivances in daily pensed with, the momentum of a train is
The necessary use, any one of which is adequate for unitiny reduced in proportion. the travelling piston to the train, and in which weight in a train to convey 200 passengers no difficulty of separation, nor apprehension of upon the locomotive system amounts to 77 any derangement, can possibly exist. Be- tons; whilst on the atmospheric system it sides, even were this not the case, this sepa- is only 33 tons. So that the application of ration or casting off is not the only means at the break on the latter system will stop a the command of the conductor; in common train in half the time that it would with with the locomotive-train he has the break, and in addition he has the power of instantly locomotive engines. Mr. Bergin has alluopening a communication between the ex-ded to these in the aboye extract, but we hausted main and the atmosphere; this latter may notice still another. of course is not so immediate in its action as When the power is turned off in a locoshutting off the stean in a locomotive, but motive engine, the momentum is checked combined with the break, which from the much by the break, and by reversing the action less weight and momentum of the atmospheric of the engines. Upon the atmospheric systrain, I know by frequent trials, (even at full speed, and with the full motive pressure in tem, the required object is, as it were, also operation,) to be much more effective than provided for in a beautiful manner by the with a locomotive engine. I believe itpracti- natural action of the principle employed. cable to bring to rest a train moved by atmos- The conductor no sooner opens the compheric pressure, in as short a space as is con- munication between the exhaustedomain sistent with the materials of the carriage and the atmosphere (which is accomplished holding together."
by the simplest means), than the very power
which had before served to impel the train, Thus, so far from its being a cause of in- now, when it is required to act contrarisecurity for the source of power to be dis- wise, tends to retard it. As soon as the tant from the train, the very reverse is the air is admitted before the piston, not only
“La locomotive porte avec elle," is the motive power stopped, but the very observes M. Teisserenc, un élément ter- momentum of the train accelerates its own rible de destruction, le feu, dont le catastro- stoppage, by compressing the air before the phe du 8 Mai, les accidents arrivés sur le che- piston ; so that its density acts as a check min de Liège, sur celui de Tsarkoé-Selo à powerful in proportion to the speed, and diSt. Petersbourg, ne font que trop ressortir minishes only as the train stops. le danger.” Similar casualties of daily The action of this same principle meets occurrence, attended with more or less mis- another question. It has been asked whechief, might be quoted. The objection ther, supposing any leakage or accident stated in the above extract has been care- should happen in the tube before the piston, fully examined by M. Mallet, who says in in ascending a steep incline, the train conclusion :-"I must add, that it is not would not run backwards by its own force true to assert that there is no communica- of gravity ? Supposing any such accident tion between the engine-man and the train. to happen, the same principle of nature The barometer, which he has continually which we have noticed would act to prevent before his eyes, ever indicates the power this result: the momentum is proportioned he is exerting over the piston, and the in- to the inclination, and the greater the speed creased or diminished velocity of the train from this cause, the greater would be the is perfectly known to him by the rising and compression of the air, --in fact the power falling of the mercury. The barometer, to resist it. This beautiful operation of a also, is an instrument which it requires principle of nature, so simple and self-advery little instruction to understand and justing, will be intelligible to every one. make use of.
We have thus noticed the chief points But independently of the removal of this alluded to in the Parliamentary Report. source of danger, it is manifest that, in the A reply to many of the statements convery point in which the Parliamentary Re- tained in it was published in the pamphlet porters ascribe exclusive safety to the loco- by Mr. Bergin, of Dublin, to which we motive system, the atmospheric has the ad- have alluded : in this he examines at great vantage of not only possessing all the length the result of the experiments instimeans of safety attached to a locomotive tuted by the Parliamentary Reporters, and
their theoretical investigations, especially between the locomotive and atmospheric with respect to the estimated expenditure systems of railway. On an atmospheric of engine-power required to maintain the line, increase of speed does not increase exhaustion in the working main-the ex- the cost of transit : the amount of discharg. hausting power of the air-pump, and the ing power expended during the transit of a proportionate amount of leakage in the given load, over a given distance, is the long valve and the piston in the main tube. same, whatever the speed; and at the same Mr. Bergin examines, in a second class of time a saving in the loss from leakage is observations, the remarks founded upon effected also in proportion to speed. On a these calculations, which he considers as line worked by locomotive engines it has mere matters of opinion, and to which our been clearly proved that an increase in the attention has been more immediately di- velocity of the train from 25 to 30 miles rected. We shall proceed to notice the per hour, is attended with a loss of more comparison of the merits of the two sys- than half the effective power of the engine. tems given by the Patentees :
This disadvantage is also attended by an“We will first notice the principal defects in other serious one when an engine has to railways worked by locomotive power. These draw a train up an inclined plane,-a diffiare, the expenses consequent upon their for- culty which augments in an increasing ramation and working, in addition 10 the impos- tio to the inclination ; an engine that would sibility of obtaining a speed beyond 25 miles draw 269.87 tons at 10 miles an hour, on a an hour, without incurring a more than propor- level of 1 in 1000, can only draw 84:07 at tionate additional expense. that would draw 61-29 tons on a level at the the same speed on a gradient of 1 in 100. rate of 25 miles an hour, would, - if required to Thus, as Mr. Pym well observes, "the travel 30 iniles an hour, only be able to draw power is lost or absorbed in the inverse ra29-06 tons, -or, for the additional 5 miles in tio in which it requires to be augmented, speed, a loss of more than one-half in power. precisely at the moment when it is most These evils arise from the following causes:
important to obtain an increase." first, from the necessity of making the roads
The following table, taken from Mr. comparatively level, owing to the nature of
Wood's Practical Treatise the power employed. The whole power of the locomotive engine is not available to impel roads, '* shows the gross load which a locothe train, because it has to drag itself and len- motive engine, capable of evaporating sixty der. Thus a great portion of iis power is con- cubic feet of water per hour, will drag, exEumed even on a level; but that loss of power clusive of the tender, at the undermenis greatly augmented when contending with tioned rates of speed, on different inclinathe slightest ascent."-Samuda, page 21.
tions of planes. This will enable the reader Here we must observe, that the velocity to estimate the advantage which the atmosof travelling offers a remarkable contrast pheric railway possesses :
10 121 15 174 20 221 25 274 | 30 of plane.
Inclination miles an miles an miles an miles an miles an miles an miles an miles an miles an
hour. hour. hour.
346 251:10 187.84 142.64 108.75 82 38 61:29 44:04 29.66
1 in 300. 175.39 124.85 91.16 67.09 49.03 34.99 23.76 14:57 6.91
Mr. Samuda states further disadvantages, consequent on the employment of locomotive of the locomotive system :
engines. These engines (exclusive of tender) "Secondly, by the necessity of having great weigh generally from 14 to 15 tons each : and, weight and strength of rails and foundation
* Third edition, page 581.