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in addition to the rigidity of road required ready shown) on inclined planes. And, lastly, to sustain this weight passing over it on the chances of accident from collision, running one carriage, the motion transferred to the off the rail, bursting of boilers, etc. From the wheels by the engines alternately on each foregoing remarks it will appear that the evils side, causes a continual displacement or forc- of the present system are entirely attributable ing out of the rails.
to the use of locomotive power, and the reine5. The third, and perhaps the greatest evil, dy must be sought for in the employment of is the heavy expense attendant on working a stationary power in its stead."--Page 24. railway by the ordinary method; and this item is rendered more excessive by the necessity of having a large number of extra engines the anticipated results of the atmospheric
With these disadvantages are contrasted in store, to keep an adequate supply in working order. By reference to the half-yearly ac
system : counts of the Liverpool and Manchester Railway, the annual expense for locomotive
“1st. The loss of power occasioned by the
power and coke is found to be from 50,0001. to locomotive engines having to draw their own 60,0001. a year, nearly 20001. a mile per an- weight is entirely avoided ; and steep hills
more additional num, on a traffic of about 1700 tons a day. may be ascended with no
This amount is exclusive of first cost and in- power than that actually due to the acclivity, terest on the original stock.”- Page 22.
as there is no weight except the train. There
is no other known power which can be applied This item is one of serious importance. weight and friction with it. The ill effects of
to locomotion without carrying considerable The Parliamentary Report states, that " in locomotive-engines have been already pointed respect of locomotive outlay, a line worked out, and the same disadvantages exist in the by locomotive engines, in order to be well application of ropes, which must be drawn stocked, should have an engine per mile along with the train, and become an increased in addition; this mode of working requires incumbrance on inclined planes. The defects water-stations, engine-houses, repairing- of ropes in other respects are too generally
known to need comment. shops, etc.” Thus the expense of all these
2nd. The weight of the rails and chairs on engines, required to be constantly out of the new system may be less by one-third than use, is exactly so much capital sunk, and where locomotive engines are employed, as yielding no interest. Nɔr is this a trilling the carriages of the train will be 100 light to matter, when we consider that each engine injure them. The annual charge of maintecosts on an average above 15001., and that nance of way, will, from the same cause, be
reduced to a considerable extent. the expense of repairs on each in the year
3rd. The wear and tear of locomotive, comamounts to above fifty per cent. All this
pared with stationary engines, is as 18 to 1. expense and loss upon capital invested is
4th. By the new system the full power of saved by the employment of a stationary the engines is always obtained; and on an inengine, upon which the wear and tear is cline, the additional quantity of fuel consumed scarcely worth consideration. We recur in ascending will be saved in descending, as to Mr. Samuda's statement:
the trains run down by their own gravity.
The expense of fuel will be further decreased, " The fourth evil is the large consumption as the expense of using coal is only half that of fuel in proportion to the power obtained ; of coke. which arises, in part from the great velocity in On the new system the velocity depends enthe movement of the pistons, preventing the tirely upon the velocity with which the air is steam from acting on them with full force ; withdrawn from the pipe; therefore, by simwhich causes a back pressure on the pistons, ply increasing the air-pump, any speed may reducing their force in proportion to the vel - be attained ; and with a fixed quantity of traicity at which they move. The power of the fic per diem, no considerable increase in the engine is thus constantly diminished as the ve- fuel consumed or any other expense is incurred locity of the train is increased. To so great for iimproved speed, further than the small adan extent is the combined action of these de- ditional pow's required to overcome the infects felt, that when travelling at 20 miles per creased atmospheric resistance. An actual hour, the effective power of the engine is re- saving in the first cost of a railway constructed duced to half that which would be obtained for high velocities may be effected, because, from the same quantity of steam generated by performing the journey in less time, a and fuel consumed with a stationary engine. greater number of trains may be despatched When travelling at 30 miles per hour, it is re- each day, and their weight diminished; thereduced to less than one-fourth; and at a speed fore the piston, having less to draw, may be but litile exceeding 45 miles, the power is so smaller in diameter. The cost of the pipe far destroyed that the engine will scarcely (which forms the largest item in the first cost draw more than itself and tender. An addi- of this railway) will thus be reduced in nearly tional waste of fuel, to an immense extent, the same proportion as the speed is increased." also occasioned by the loss of power (as al- --Page 26.
M. Mallet, in his report to the French for a loan of money, 'on the security of their Government, makes an important observa- existing railway, to carry on the works. In tion on the effect which a reduction of the meanwhile, the Report above alluded to speed, in the passage of a train, exercises had been delivered to the Board of Trade, upon the motive force. In describing vari- which fully admitted the accomplishment of ous experimental trips which he made on the principle of the atmospheric railway, in the Dalkey line, he says, that in one jour- the following words: “We consider the prinney, when travelling at the rate of 45 miles ciciple of atmospheric propulsion to be esper hour,
tablished, and that the economy of working
increases with the length and diameter of the “During our course the barometer sunk to
tube." With a creditable public spirit, the 21 inches: this fall was caused by our going Government consented to assist in the trial of on quicker than the air could be withdrawn. this national undertaking, and granted a The air which remained in the pipe caused a loan of £25,000 to the Dublin and Kingscondensation which lowered the barometer. In town Company. The Company however the following experiment, made with the same could not obtain a line of road without applytrain, a contrary etiect was produced. Set off al 8 inches, viz. with a power of 704 lbs. We ing for a bill to Parliament; and to obviate went on very slowly, and saw the mercury rise the delay and expense which this would octo 20 inches gradually. In this manner the casion, the Board of Works granted them the air-pump produced a vacuum quicker than we use of ground in their possession, which had proceeded, and this is a very important point been used for conveying stone from the quarof the atmospheric system. If a slackness ries near Killina to the harbor of Kingstown. is produced by overloading a train, or if the The nature of this road presented every diffitrain stops, the propulsive force instantly aug- culty to the formation of a railway; neverments.”--- Page 16.
theless the Patentees felt such a confidence
in their project, that they were glad to have We shall not enter into further details of it tried and tested for the first time under the probable saving to be effected by em- circumstances of such unusual difficulty. ploying atmospheric pressure on rail-ways. The accomplishment of the work may on The calculations of the Patentees show a this account be regarded as doubly importlarge estimated reduction of cost in the con- ant. From the nature of the line of road, struction and laying down of a line on their a series of sharp and difficult curves was plan, and a saving of more than one-half in unavoidable, upon which no locomotive enthe annual cost of working; and we have gine could run without the utmost risk, and some guarantee for the general accuracy of at a slow pace. These are now passed with their calculations in a comparison of their the greatest ease and smoothness at sixty estimates with the actual cost of construc-miles an hour, and with loads attached of tion of the line at Dalkey. This gives us seventy-two tons at the rate of twenty miles. ascertained data. The cost of the appara- Another point has here been decided, upon tus complete, and placed on the line, is which in fact the applicability of this rail43001. per mile; and that of the steam-en-road to extended lines of traffic in a great gines, vacuum-pumps, engine-houses, etc., measure rests,--namely, the power of pass10001. : in all, 53001. At the same time ing with facility from one section of pipe to we must here mention the remark made by another. At present, only one section of M. Mallet, in describing this apparatus, pipe is in operation, and consequently this that the engine" is evidently more power- experiment cannot be fully shown ; its sucful than is required for working this road :"/cess however is ascertained by the fact, he adds,—"I am informed that it would that the train has repeatedly passed off one make a vacuum in a pipe of six miles long : section, with the greatest ease and regularthey rarely work this engine to more than ity. The operation of the valve which half its power at present."
divides the sections is simple and beauIn consequence of the success of the tiful,--we have already quoted M. Tiesexperiments at Wormholt Scrubs, the com- serene's description of this,-and the simpany of the Dublin and Kingstown Rail-ple fact of the successful operation of this way, backed by the opinion of Mr. Pim, ex- valve is conclusive. If a train can pass pressed their desire to adopt the atmospher- without stoppage off one section, it must ic principle in an extension of their line necessarily enter at once upon the next, from Kingstown to Dalkey. In furtherance and there can be no question as to the faof this object they applied to Government cility of repeating this along a line of any
length: a hundred stations can as easily be from it, containing the results of trials upon passed as one.
the Dalkey railway, which are of great inThe excellent Report of M. Teisserenc, terest :to which we have had occasion to refer, was founded on observations made upon obtenu d'une manière plus parfaite qu'on n'au
Après avoir reconnu que le vide était the experimental line at Wormholt Scrubs. rait osé l'espérer, je me suis occupé de la After detailing the difficulties and dangers vitesse. Je rapporterai ici quatre riences. attending the locomotive system, he thus 1. Avec un convoi pesant 38 tonnes (la compares it with the atmospheric :
tonne anglaise est de 2240 livres), le baromè
tre marquant 25 pouces, l'on a monté en 3 min“Le système atmosphérique est exempt utes 15 secondes. Par prudence, l'on a emdes défauts que nous venons de reprocher aussi ployé les freins pour franchir les courbes, ce bien aux locomotives qu'aux machines à câbles. qui a produit un ralentissement. Le maxiSon application dispenserait à la fois et du mum de vitesse, dans cette expérience, a eté de poids inutile du moteur dans le premier sys- 40 milles (16 lieues) à l'heure. tème, et du poids inutile de l'intermédiaire dans 2. Avec le niême convoi, l'on est monté en le second; elle permettrait l'excessive division, 3 minutes 7 secondes: maximum de vitesse, 45 l'excessive muliiplicité des trains, sans accroî- milles (plus de 18 lieues). tre les chances de collision, comme cela a lieu 3. On est parti, le baromètre marquant 8 dans le système locomotif; sans augmenter la pouces, avec le même convoi. Pendant le dépense, résultat de l'emploi des locomotives trajet, le baromètre est monté jusqu'à 20 ou des machines à câble, elle fournirait un mo- pouces. Le voyage a été effectué en 4 minutes teur dont la puissance, bien loin de diminuer 30 secondes. Sur quelques points,l'on a marché avec le poi Is des objeis à traîner, avec la roi. à 30 milles (12 lieues). deur des rampes à franchir, tendrait, au con- 4. Enfin, le baromètre marquant 25 pouces, traire, à croître dans le même sens. Elle ren- l'on est parti avec un convoi de 69 tonnes. Le drait possibles toutes les vitesses avec des temps du trajet a été de 5 minutes 20 seccharges utiles considérables, sur les chemins ondes. les plus planes comme sur les railways les Pour descendre, l'on a employé la gravité. plus inclinés. Bien loin de nécessiter une ap- A cet effet, l'on a rangé le piston de côté (ce plication lente de la puissance motrice au dé- que se fait avec la plus grande facilité), afin part, un ralentissement progressit à l'arrivée, qu'il ne recontrât pas de tube. Le temps de la elle permetirait d'accumuler à l'avance la force descente a été d'environ 5 minutes. Le notrice, de manière à imprimer rapidement mouvement était ralenti par le frottement dans aux trains leur maximum de vitesse. Avec les courbes. Je n'ai rien à dire de ce moyen, elle seraient impossibles et les collisions et les usité par plusieurs chemins de fer." accidents résultant de la présence du seu. Les sorties de rail deviendraient extrêınement dilli- The following results of experiments ciles; les effets de la force centrifuge très peu subsequently made on the Kingstown and redoutables; puisque le train, composé au Dalkey line are extracted from the 'Railplus de deux voitures, serait étroitement lié à la voie. Enfin, construits pour recevoir des way Times' of December 2, 1843. Their voitures trois et quatre fois moins lourdes
importance justifies our inserting them at
que les locomotives, les chemins n'auraient plus length. besoin de rails aussi pesans, de points aussi résietants ; les collisions n'étant plus à craindre,
“Without the slighest hesitation, we have pas plus que les encombrements, puisque les to state that the result of very minute inmarchandises voyageraient aussi vite que les vestigation on the spot has fully confirmed the voyageurs, une seule voie serait suffisante. opinions to which we had previously come, Rien de plus simple, d'ailleurs, que la théorie from the scientific discussion of the principle de l'appareil au moyen duquel on réalise ces
and from the operations of the very imperfect nombreux avantages."-- Page 108.
apparatus at Wormholt Scrubs.
" The line between Kingstown and Dalkey This Report awakened the attention of is 13 miles in length, in which there is a rise the French Government; and as soon as
of 71} feet, making an average ascent of 1 in the works at Dalkey were in a sufficiently the rails, which is 15 inches internal diameter,
115, towards Dalkey. The main pipe betweer: advanced state, they sent over another en commences at the Kingstown station, and is gineer, M. Mallet, Inspector General of continued to within 500 yards of Dalkey. The Public Works, to furnish a second report. communication between the main pipe and the This recently appeared in the French jour-steam-engine (at Dalkey) is formed through nals, and we shall extract a few passages trackway, and attached at the lower end into
, * Great credit is due to the engineers, Messrs. the main and at the upper end into the vacuSamudas, for the skill and talent displayed in um pump: A branch valve is placed at the constructing the Dalkey railway, and improving junction between the close and open main, many of the details of working.
which allows the vacuum pump to act on the
main, or be shut off from it, at pleasure. The “The scale employed on the Dalkey line is dimensions of the engine are, -cylinder, 344 -Vacuum tube, 15 inches diameter ; vacuum inches diameter; stroke, 5 feet 6 inches; speed, pump, 67 inches diameter; engine, 100-horse 212 feet per minute. It works expansively, the power. It will be well to notice the duty such steam being admitted in the cylinder at 40 lbs. an apparatus will perform on a level and up above the atmosphere, and cut off at one-fourth various rates of inclination. This proportion stroke when the engine is at its full load; it is between the pump and the tube enables trains then expanded for the remaining portion of the to be propelled 50 to 60 miles per hour, and stroke, and condensed in the usual way. The will draw a train of 200 tons on a level. degree of cut-off is regulated by a cam worked Willdraw 80 tons up an incline rising 1 in 160. by the governor, and is therefore proportion
1 in 140. ately shorter as the duty of the engine is less;
1 in 120. but in no case is the steam admitted for a
1 in 100. greater distance than one-fourth of the stroke.
1 in 90. The vacuum-pump is double acting. The di
1 in SO. mensions are,-diameter, 67 inches; stroke 5
1 in 70. feet 6 inches; speed, 242 feet per minute. With
1 in 60. the above apparatus we saw a vacuum formed
1 in 50. in the entire length from Kingstown to Dalkey
“ The cost of the atmospheric apparatus Equal to a column of mer. 10 in. (ory of an atmos.) in 0 56 complete, and placed on the line, is £1300 per
15 “ (or
) in 1 51 mile; and of the steam-engines, vacuum20 “ (or
) in 3 30
pumps, engine-houses, etc. £1000; total, For the purposes of observation, distance posts | £5300. It would scarcely be useful to notice were placed along the line at intervals of two the other items that are necessary to complete chains, every tenth post (or one-fourth mile) a railway on this system, as the earth work having a distinguishing mark; and the follow- will vary materially according to the nature ing was the result of some journeys made for of the country through which it passes. In a us during our visit:
difficult country the saving from adopting such “Journey A.-Gross load 62 tons; max-gradients as would be suitable for ihe atmosimum speed during trip for two chains was= pheric instead of the locomotive, would con24 miles per hour ; total time of journey, 4 siderably more than equal the entire £5300, minutes 43 seconds.
while on a level or easy country a balance of " Journey B.-Gross load 72 tons; maxi- expense would remain against the atmosphermum speed during trip for 2 chains was = 20 ic system up to this point. In all cases the miles per hour; lotal time of journey, 5 min. smaller quantity of land that would be required,
the diminished size of the bridges, the lighter “Journey C.-Gross load 75 tons; maximum rails, the absence of all coke and water-staspeed during trip for 2 chains = 21:17 miles tions, workshops, and stock of locomotives, will per hour; total time of journey, 6 min. 2 sec.
have to go to the credit of the atmospheric Journey D.-Gross load 30 tons; maxi- system against the cost of vacuum tube and mum speed during trip for 2 chains was
engines.” 51.5 miles per hour; time at passing 1 1-2 mile post 2 min. 57 sec.; total time of journey, 3 min. 24 sec."
“ Among some interesting experiments
made at Dalkey are the following. The first In the same journal of December 16th series shows the uniformity of the sealing appeared the following additional details :- process. During the same day, and after the
" In following up the investigation, it should running of each train, observations were taken be observed that local circumstances, amount the height of 15 inches, which was as fol
of the time required to re-form the vacuum to of traffic, and steepness of gradients, will to a
lows:-certain extent influence this consideration; but with the view of rendering it as generally ap
After the 4th trip the barometer rose to plicable as possible, we have made the calcu
15 inches in 1' 45' lations on a similar scale to that in use on
in 1 40 the Kingstown and Dalkey line, and have
in 1 43 deduced such of the working expenses there.
in 1 40 8th
15 from as the time it has been in operation will
in 1 45 allow.
in 1 40 We apprehend that this scale will
15 never have to be exceeded on lines of the
in 1 42 largest traffic. Where it is decreased the cost
in 1 45
21st will be proportionately lessened, so far as re
in 1 45 gards construction. T'he decreased scale will
in 1 43 only influence the weight of trains. The 6 The second series shows the amount of speed can be preserved on the smaller as on leakage due to the longitudinal valve, as sepathe larger scale, by maintaining the same rela- rated from that due to the air-pump, travelling tive proportions between the vacuum-pump piston and station valves. In the following and the main.
experiments the vacuum was in every instance
raised to 22 inches; the engine was then stop- , fourth gives the comparative cost of workped and the tube was allowed to fill with airing on the two systems. We have had ocby the leakage (from all sources) into it.
casion to cite many remarks contained in With the train at Kingstown,
this Report, regarding the general merits of the gauge fell 18 inches, i. e. from 22 inches to 4 inches, in 11 33-100th,
the atmospheric railway; and it is unneAdvanced 1-4 mile
in 10 88-100th,
cessary to review it critically. It is the Advanced 1-2 mile
in 10 76-100th, most valuable document that has yet apthe leakage being at the rate of one inch in peared on the subject : the chief part is oc36.83 sec. in the first instance, one inch in 36 cupied with a minute and careful detail of sec. in the second instance, one inch in 35.91 the experiments which M. Mallet instituted sec. in the third instance, -showing the addi- on the Dalkey railway, and upon which his tional leakage from the long valve to be only opinions are founded. These merit a close so much as was represented by the gauge fall- examination, and will be peculiarly valuaing per inch $% of a second quicker in the first instance and 6 of a second in the last
, ble to scientific men interested in the suband the additional power to compensate this ject of railways. M. Mallet examines being all the increased haulage power required every advantage and disadvantage of the per half mile. This is an experiment of no atmospheric system,-its applicability to ordinary interest, inasmuch as it confirms the existing and new lines, and under every notion that the advocates of the system have circumstance attending construction. The long urged for it, namely; that every extension English translation of this Report is of much of the length is attended with increased ad- less value than it might have been, had the vantages, and that while the Atmospheric Railway is equally applicable to short as to French measures and values been reduced long lines, it is by no means applicable only to the English equivalents; but a point of to the former
, which its successful application still greater importance (and which we are on a short line has induced many to imagine.” surprised not to see noticed by the transla
tor) is, that all the calculations of M. MalWe had cited the above experiments, be- let are founded upon the French prices of fore the appearance of M. Mallet's Report; iron and of labor-naturally so in a report they however give substantially the same addressed to the French government; but results and figures, but in a con- unless this fact is borne in mind, throughdensed form. Subsequently to the appear- out the calculations, and the difference noted ance of M. Mallet's first report in the between the English and French prices of French journals, a second and more detail- iron, the reader is liable to be seriously ed one, addressed by him to the French misled. Prernising this remark, we obgovernment, has been published in Paris, serve that M. Mallet calculates that, in the and an English translation in London. cost of construction, the atmospheric system That gentleman states, that “the fame of would effect a saving of one-seventh, and the success of this second experiment, in the cost of working a saving of twomade on a scale far greater than that at fifths. The same calculation, made upon Wormholt Scrubs, spread itself into France. the value of iron in England, would show Immediately M. Teste, the minister, and of course a much greater reduction. M. M. Le Grand, Under Secretary of State Mallet examines carefully and impartially of the Public Works, whose attention had every objection which has been, or is likely been roused by the previous report of M. to be, raised to the atmospheric system; Teisserenc, desirous to know all the im- and in concluding this part of his Report provements and advantages of a system he says :which might exercise so great an influence on the future prospects of rail-roads in
"I do not think I have omitted any of the France, gave me an order to embark for objections which have been pointed out to me. Ireland."
Several are worthy of being taken into consid
eration. But do any of them present insurThis Report is divided into four chapters: mountable difficulties ? Are they of a nature the first contains a description of the line to induce us to abandon the invention ? I do from Kingstown to Dalkey, of the apparatus, not think so, and therefore I advocate a trial. and details of experiments; the second If the system had already arrived at perfection chapter treats of the application of the at- no trial would be necessary; we should have mospheric system to railroads in general:
but to lay down the works, certain of sucthe third gives the comparative expense
cess; but in spite of the enormous step shown of
to have been gained in Ireland, much yet relaying down a locomotive railway and mains to be done. Let its judges remembe one on the atmospheric plan; and the what the locomotives were at their commence