Lapas attēli
PDF
ePub

Gross

per

in

10

.82

STRICTURES

ON

THE

REPORTS OF

THE

STATE ENGINEERS.

ed.

this point, we hope soon to be able to speak || to wit: 2ks part of weight of engine and the regular curve represented by the contimore definitely

tender, and qšo part of the cars and their nued line A. B. D. E. F. and N., and in the We desire to call the attention of our loads. And aly, The resistance caused latter ease the irregular curve, represented teaders to an article from the Journal of the by gravity which occurs upon inclined roads, by the broken line a. b. d. e. f. and n. The Franklin Institute, in relation to this en. and which corresponds, (according to the first coinciding, as would naturally have gine, published in No. 13 of this Journal-established principles of mechanics,) with been anticipated, with the regular decrease and also to one in the same number, signed the size of the angle of inclination. of the effect produced under a gradual in“HIERO,” as they will, we believe, with To reader the preceding principles appli-crease of the elevation of the plane on this statement of facts, tend at least to shake, cable, the inclination of the road must be which the power operates, while the latter if not to dispel, some of the prejudice within that limit on which the friction of is evidently in direct violation of the law against, or disbelief in the power and utility the wheels of the engines upon the rails is which connects cause with effect, in the of, this engine. If more particular informa-sufficient to allow of the exertion of the case under consideration. tion is desired, it may be obtained by ad-full working power of the engine.

The preceding is conclusive as to the dressing, post paid, William Avery, or E. According to the principles above laidmanner in which the table presented in the Lynds & Son, Syracuse, New-York, or Mr. down, and assuming the gross load upon a Report was formed. The process as deJoseph Curtis, the agent for this city, or level to be as above stated, to wit: 75.25 clared in our last number, must have been the Editor of this Journal.

tons, the weight of the engine and tender an empirical one, as calculations made upon By the way of comparing it with other being taken at ten tons, the following re true principles could never have led to such engines, we shall feel greatly obliged to any sults are obtained :

discordant results. gentleman who will give us a statement of

We have dwelt longer upon tbis branch

Inclina-Load in Correctthe water and fuel used, and labor performed,

tion of Tons ta- ed Gross

Error

of the subject than its importance would by a piston engine of fifteen horse power!

Diff.
Road pr. ken from Load

perhaps seem to demand, but as the stateMile in the

Tons.

Cent. When received, we will lay it before our

Feet.

menis in the Report were evidently put for

above Tons. readers.—[Ed. R. R. JOUR.]

Table.

ward with some pretension to science, we THAMES TUNNEL.–We commence, in this

have felt it a duty to lay bare the foundaLevel 75.25 | 75.25

tion on which that pretension rests. number, a concise description of the Thames

49.53 47.80 1.73 4 20 37.35 33.72 3.63 11

We now proceed to give a statement of Tundel, with views_and shall continue it

30 27.24 25.15 2.09 8 the comparative force of traction of engines in a subsequent number-after which it

40 20.22 | 19.40

4

on the Baltimore and Ohio Road, as deduced will be published in book form.

50 17.04 | 15.26 1.78

12 60 13.92 12.14 1.78 14

from the experiments referred to in our last
For the Railroad Journal.
70 11.31 9.71 1.60 16

No.
Our readers will perceive that the amount

Engine as as-Arabian En-Geo. Washing.

sumed in Re- gine, veloci- ton Engine, of the variation or error of the results as (No. III.

Inclina- port, with re- iy 11 79-100 velocity 114 tion of

sults correct. Miles per Miles per We again quote from the Report of John given in the Report deviates from the truth

Hour.

Hour. B. Jervis, Holmes Hutchinson, and Frede. from 4 per cent. up to as high as 16 per Feet per

Mile.
Ratio
Ratio

Ratio rick C. Mills, on the comparative merits cent.! It is therefore evident that the re

Tons. sults given in the Report could not have

Tons.

Tons. and cost of Canals and Railroads, Doc. 296,|| been formed by the aid of correct mechani

Level

Level Level p. 33, of the last session of the N. Y. Legis- || cal and mathematical principles. Indeed Level 75.25 113.00 211.00 lature, as follows

Feet

the results themselves exhibit this fact on 10 47.80 63 73.08 65 139.20 66 por "Tons. their very face.

20 33.72 1 44 52.62 47 102.38 48 mile.

30 25.15 | 33 40.16 36 79.99 | 38 "On a level the gross load will be

75.25
: It will be obvious to most of our readers

40 19.40 25 31.79 | 28 64.93 31 ! On a road or section having an ascent of 10 49.53

that the effect produced on the several in 50 15.26 | 20 25.78 23 54.11 25 20 37.35 30 27.24 clinations, (increasing as the latter do by a

60 12.14 | 16 21.24 | 19 45.96 22 40 20.22 common difference of 10 feet) must regularly

70 9.71 | 13 17.71 | 16 | 39.60 19 50 17.04

80 7.76 10 14.87 | 13 34.50 16 diminish by some particular law. In the

90 6.16 8 12.55 11 30.32 | 14 70 '11.31':|| results given in the Report this law is evi 100 4.83 10.61 | 10 | 26.83 / 13 We demonstrated in our last No., that the

dently violated. absolute power of the locomotive engine as

The following are the second differences:

The rates here given for the Geo. Wash. exhibited in the above table, whether upon 13.54 2.07 3.09

3.84 0.06 0.51

ington and Arabian engines, for different a level or inclined road, was rated altogether

The same differences drawn from the ascents, are below the actual performance of too low, being from 50 to 100 per cent. short corrected results are as follows:

those engines. This is principally owing, of the results obtained by experiments ac 13.37 5.51 2.82 1.61 1.02 0.69

we presume, to the fact that the friction, intually made for months previous to the time To render the discrepancy more apparent

stead of being zo of the gross load, as when the Report in question was rendered. we have framed the following diagram, in assumed, is probably the mo or zov part. We e present the table a second time, for the

The second column contains the corrected purpose of showing that the relative results || 7

results as ascertained above, for different therein given for different inclinations, could

6. S:

inclinations, the gross load being the same not have been estimated by correct formula,

id
B В.

as assumed in the Report, viz: 75.25 tons. and were not in accordance with the “most

The fourth column shows the force of trac. approved” experiments and facts, as they

7

tion of the Arabian, and the sixth that of existed at the time the Report was written.

the Geo. Washington engine. The AraIn determining the resistance to be en

bian was in operation, and an official statecountered in the movement of a train of

ment of its

performance rendered for cars, under the circumstances as assumed

months previous to the Report under con. in the table, two things are to be considered. I which the second differences in the second | sideration being made. We expressed, in 1st. The resistance arising from friction, line are represented respectively by the or

our last No., our surprise that the improve. and the want of perfect smooihness and dinates HA, SB, RD, &c., and those in the inents on the Baltimore Road were not reregularity in the rails and wheels, which first line by Ha, Sb, Rd, &c. Conneering ferred to or noticed in the Report. Had we will assume the same as in the Report," the extremities of the former, and we havell they been sairly presented, the complexiog

to a

to a

toa

[ocr errors]

66

[ocr errors]

46

60

13.92

[merged small][ocr errors][ocr errors][merged small]

WITH WATER.

of the results given in the Report would || cessarily be greater. Such an engine will mand the top of the highest building in that have been materially changed.

convey a load up an inclination along which division, and of capacity sufficient to sup. The gross load conveye1 on a level, in a weaker engine would not be able to pro-||ply the largest fire ascertained for two stead of 75.25 tons,would have been 113 toos,|| pel its own weighemor an engine may be hours-a small steam engine or other ap. an increase of 50 per cent. At 30 feet per so weak as to have its power entirely ex- paralus would be required to raise the mile, 39.72 tons instead 25.15, being an in- hausted on a very moderate inclination. In water, and if it were a steam engine, it crease of nearly 60 per cent. At 70 feet pereither case the absurdity of the principle could always be heated and in operation mile, 17.70 tons instead of 9.70 ions, an in- | asserted in the Report is apparent. We witbin the time specified, renewing the crease of nearly 80 per cent. It is true that are not surprised at this; it only comprises supply. From this reservoir four inch pipes the Arabian engine was heavier than the what we have already had occasion to infer, would branch into every street of the divi. one assumed in the Report, being 74 tons, that the mechanical principles of the ope. sion, and at the corners of all the streets, and the latter being 64 tons, but it had one andration of engines on inclined roads could within frequent distances on these streets one third times the power.

not have been thoroughly understood by the fire plugs would be placed raised above the A difference so great, it will be at once writers of the Report.

pavement, occupying but little space and perceived, would have materially affected It is almost needless to add, that the ab-having quadration cocks, within a proper the cost of transportation upon Railroads ; | solute and relative cost of transportation case, with a common key, one of which as exhibited in the Report, the reduction per ton per mile, on different inclinations, would be in the hands of the foreman of in the expense being greater in proportion as exhibited in the Report, is necessarily every hose company, and one also lying u pon the higher or steeper grades.

erroneous. Themanner, likewise, in which with some respectable house in the neighIn the sixth column above, are the results the cost of transportation on different incli-borhood. No part of this water would deduced from the performance of the Geo. nations is represented, is calculated to mis- be permitted to be used for any other Washington engine. This engine was con-| lead those who are not particularly conver-|| purpose ; sınall pipes of if or 2 inch, struc ted subsequent to the rendering of the sant with the subject, since no allowance diameter would be carried into such propese Repori. The statements in relation to it appears to be made, or intimation given, of|ties as desired them, running up the inside of are introduced here with a view of exhibit the very great saving in power in descend- the front wall to the top of the house, and ing the present state of improvements in ing, which invariably occurs in a reciprocal || having a communication with each story, the application of locomotive steam powertrade.

always open, and charged when necessary upon Railways. It is presented likewise We shall resume this subjeet in our next by means of the stop-cock on the street. for the purpose of exhibiting to our readers | No., and examine particularly into the prin- | 'These and various other arrangements the character and extent of the improve-||ciple adopted in the Report of reducing in- easily suggested could very conimodiously ments which ha ve been made upon the Bal- clined roads to equivalent level ones. and profitably be introduced. timore Road, within the last three years,

Owego. A very important item of the city water. and impressing their minds with the degree

is at present used to extinguish fires-this of credibility and ii aportance to be attached ||ON SUPPLYING THE CITY OF NEW-YORK | water might as well be salt or river water to the performances of the Arabian engine,

as any other. My opinion is, that the and also for another purpose, which will To the Editor of the Railroad Journal:

Fire Department, to be effective, should have appear hereafter. The power of the Geo. Sir,- The supply of water now being the entire control of the water appropriated Washington was two and a half times that brought into New York from the Crotod | to its use: at present the individual com. of the engine assumed in the Report, while river, will be very ample and of the best||panies are beautifully arranged and the its weight was only one third greater. quality, and it will doubtless, by admitting engines ably manned, yet in such a city as

We will conclude this number by com- of a more copious supply in cases of fire, || this, there is wanting a more complete sysmenting upon the following, pages 33 and contribute as well to the further security || tem of defence against this destroying ele34 of the Report :

of property as to the general improvementment than at present obtains. Compared “There are engines of a larger size than of the health of the city. I have always, with the amount of property annually conthe one assumed, but it is the most approved however, inclined to think, with what pro- sumed, the cost of such an experiment at this time in reference to the weight of en- priety remains 10 be seen, that that portion would be but a trifling tax. gine and the weight of the working wheels. of the water necessary to the supply of the

Respectfully,

S. D. This, however, is unimportant, as the com- Fire Department, considering the great

Boston, Feb. 18, 1836. parison will not be at all affected by varying the power of the engine. The ratio amount of property annually consumed in [It has been objected to the use of salt between a level and the ascents will remain this way, should be seperate from that used water—that the pipe stop-cock, and all cocks the same notwithstanding.”

for family purposes; in fact, that for the of metal liable to its contact are injured, and The assertion here unequivocally made,||extinction of fires there should be a distinctio some instances rendered useless. The that the ratio of the effect produced between | supply and mode of supply, distinctly go- great injury to furniture, &c., in houses de. a level and the ascents is not affected by the verned and independent of the contingent|luged with water, (as is often the case,) to power of the engine, is incorrect both in accidents which sometimes affect the other. prevent the spread of a conflagration. How. theory and practice.

In view of this, the excellent waters of lever, salt water is better than no water.] A glance at the statements above given, the Croton would be reserved simply for the in relation to the powers of the different personal use of the inhabitants—a system

Professor Barlow's REPORT ON RAILengines, shows that the gross load which of fire police would be established contain ways.

5.- In the London Mechanics' Maga. the Geo. Washington engine is capable of|ling within itself all essential requisites, || zine for February, which has just come to conveying up an inclination of 70 feet per and capable of progressing in improvement|| hand, we find some extracts from the Remile, has a ratio compared with a level oneindependent of the control or opinions of ||port of Professor Barlow, who was apand a half times that of the engine assumed | other departments. This system, subject as

pointed by 1h Directors of the London and in the Report, and for an inclinaiion of 100|a whole to the city, had better consist of

Birmingha Railway Company to visit feet per mile, double that given in the Re-various independent divisions, each con.

the Liverpool and Manchester Road for the port. It is obvious that as the power of the nected with the North and East river. My engine is increased, the gross load conveyed || ideas in the present immature view of the purpose of ascertaining the best form of will be greater compared with its weight,|| subject, would be to attach a reservoir to rail, chair, &c. &c. and that the effect produced on any given each division, situated on the river, and The report, judging from the extracts, inclination compared with a level must ne-" having its fank sufficiently raised to com.H promises much useful information on the

[ocr errors]

subject, and we shall endeavor to obtain it||men themselves, whose judgment must suf-, secure, were only of a certain amount; but and publish it entire.

fer depreciation by such discordance. Opin-when the rails were unlevel, or other irreguSince the publication of his first report

ions derived from long experience are ex-larities occurred, some lurch would take (of which we gave a full abstract in Noceedingly valuable, and outweigh all oth-place, towards the middle or end of the 612), Mr. Barlow has been again engaged | ers, while they are consistent with facts train, which would strike the rail with suffiby the Directors of the London and Bir- and with each other; but they are worse cient force to throw up the index to nearly mingham Railway, " to visit the Liverpool than useless when they lead, as in this in-double its previous amount, indicating, of and Manchester Railway, to view that line, stance, to directly opposite conclusions. course, that it had, in the case in question, and advise this Board as to the weight of

"In making ihese remarks, I beg to be sustained a deflection nearly double what it rails, the description of chairs and fasten- understood as intending no disrespect to the would have done with the same weight in a ings, the distance of the supports, and the opinions of practical men generally, but quiescent state." size of the blocks that he would advise the simply to show that it was impossible, in Numerous and varied experiments with Directors to adopt ; and to accompany such this case, for me to be guided by them, and this instrument, while they indicate a small advice with any observations generally on thereby to justify the plan I soon deter-increase of deflection with increase of velothe subject."

mined to adopt; viz. to avoid, as farcity, seem also to have ascertained that it Accordingly, accompanied by two of the as possible, argument founded on mere hy is too small to need much addition to the London Directors, and met at Liverpool bypothesis, and to substitute for the latter

, strength of the rails; for on comparing these two of that town, he entered on his task, facts drawn from actual experiments, which observations with those made at Woolwich furnished by the liberality of the Liverpool should be made publicly, registered gene- with quiescent weights, it may be doubted and Manchester Railway Company with rally, and witnessed by any one interested whether, when allowance is made for the every necessary facility and accommoda- in the decision; and moreover, as I intended

manner in which the deflectometer was used, tion. to rest my report entirely on these data, I

any real excess of deflection was occasionThe following extract, besides showing resolved to offer no opinion, till I had time|ed by the passing load. This, however, the necessity of the investigation, presents to analyze and compare my results. I am was not the case with the joint lengths, a vivid and faithful picture of the uncer. not certain that this plan of proceeding was where the deflection was 40 per cent. additainties and contradictions into which prac- quite what the deputation most approved, |tional ; it is not suggested how this is to be tical men fall when they despise the help but I feel convinced that it was the only prevented, but it is attributed partly to the of theorists, while it gives, and on proper way in which justice could be done to the looseness of the chair and block. grounds, the weight unquestionably due to inquiry, and confidence obtained for the de

It seemed desirable to know, whether the the opinions formed by these same practicalcision.”

The dimensions of a railway-bar to sup- the outward rail in curves, required an ad

deflection produced by lateral pressure on men from constant observation :

“We met as appointed, at the Liverpool port any given quiescent load had become dition to the strength of the rail in that direcstation of the Liverpool and Manchester pretty well known, but practical men doubtline, and employed the first day in examined and differed as to what was required by constructed of a somewhat different shape.

tion ; for this purpose a deflectometer was ing the state of the rails, chairs, and blocks, | an engine and train in motion, whether modes of fixing, and other particulars. In more or less, and how much. Knowing cient for their work in other respects, would

The result, however, was, that rails suffithe course of this examination, I took the that the results of theory, when opposed to opportunity of inquiring on the spot the their previous opinions, obtain little confi.not fail under this strain, so that the subject opinion of the resident engineers, condence from practical men, and would, there needed no further attention.

The deflectometer rendered very appatractors for repairs, workmen, and others, fore, be slighted by part at least of those relative to these several points ; but I was for whose guidance ihe inquiry was under-rent the importance of placing the blocks much disappointed to find those opinions, taken, the Professor wisely resolved to found in every case opposite to each other. Until in most instances, discordant, and in many | his Report on experiments alone ; and this and other precautions are taken, the directly contradiciory; a circumstance the these are happily such as may be repeated constructors of railways must be content to more remarkable, as one would havethought at any time, and at small expense, till the use rails very much heavier than the work that five years' incessant practice would results from them are established beyond of the road actually requires :have been sufficient to eradicate many early dispute. A horizontal lever, of which the

" In consequence of the imperfection of erroneous ideas.

arms were as 10 to 1, was mounted between these parts (the blocks, &c.), a strain is oc“I am not myself a practical man, but centres on a plank; its short end was placed | casionally thrown on the rail which produces from my situation and pursuits I have been in contact with the under side of the rail, || a deflection about double that which belongs for nearly thirty years in almost constant and the other showed the deflection ten to the load in question. This effect was intercourse with two of the largest and times magnified. The effects produced by frequently and obviously exhibited in the exmost varied mechanical establishments in the passing engines and trains were mi- | periments with the trains. In many cases, the kingdom, and have, during that time, nutely observed with this deflectometer ; and the deflectometer showed only the common witnessed or superintended a vast number several instruments were provided, and amount of deflection when the engine (by of experiments and trials on various me- used at once, so as to show convenienily far the heaviest load) passed over ; wherechanical subjects, many of which I have the effects produced on different parts of as, perhaps in the middle, or at the end of afterwards been enabled 10 examine in the the bar and its supports, by the passing of the train, a wagon would lurch over from works at large; I am therefore, to a certain the same load. Though some objections | some irregularities, and throw up the index extent, acquainted with what theory gives, might be made to the manner in which it to double its former amount. This effect and what practice requires, and the limits was used, and, consequently, to the argu- was very particularly noticed by the depuit prescribes ; so I am also with the views ments for rendering its indications compara-|| tation, Directors, Proprietors, and other and arguments of practical men, who 1 ble with those of former experiments, it is parties present. It follows, therefore, that know sometimes, like other persons, in their certain that it has already furnished im- till greater perfection can be obtained in anxiety to avoid one evil lose sight of other portant data, and that it will become one of railways, a strength of bar more than doucollateral evils, which their remedy in the most indispensable instruments to the ble that due to the mean strain must be procreases or creates; but I must say that I railway engineer. Its first trial produced || vided. In former report, I have allownever saw this so strongly marked as on the following lesson for railway managers, ed 50 per cent. beyond the double, as a the present occasion, nor such a diversity of which surely will not be lost upon them : surplus; but from these experiments, it apconflicting opinions on what appears so

“Our first experiments were only tenta-pears this allowance is in excess, and that simple and plain a case. This is a circum- | tive, with a view to try the instrument, but from 10 to 20 per cent. beyond the double stance much to be regretted, not only as even in these much was very distinctly | will be sufficient ; that is, for a 12-ton enregards the doubts which it naturally shown; when, for example, a train passed gine, as the weight is at present distributed, throws upon the mind of proprietors, em-over, we could see clearly the operation of a strength of 7 tons would be an ample probarking large amounts of capital in the un-| each wheel upon the rail

, which, where these vision, and with greater accuracy of condertaking, but also in respect to practical were well laid, and the joints and blocks struction, such as the care now taken may

my

be expected to ensure, a less strength would || It was then put into the press, and the trains || would admit a plain single Trail; but, as be sufficient ; or rather, allowing the same brought on as usual, under the superinten- | the rail he decidedly recommends has a strength, an engine of 14 or 16 tons mightdence of Mr. Edward Woods and Mr. John bottom flanch, it is proposed, that, where be passed over with the greatest confidence. Gray; Mr. Locke himself being obliged to the blocks fall, a protuberance shall be left

* By referring to the observed results in leave just at the time the experiment was on the middle rib, so as to fill up its thickthe Appendix, it will be seen, that one railin progress.

ness to a level with the perpendicular face is sometimes depressed by one wheel a “ Mr. Rathbone, Mr. Edward Cropper, of the bottom flanch. A rail is thus obtainquarter of an inch, while the other wheel is and myself, were also present, and the re-||ed which admits the use of a plain chair ; perhaps on a block; and immediately after sult was, that the bar thus mutilated showed but the adaptation of particular spots to the the high wheel is depressed, and the lower greater strength than the mean strengthchair seems to bring on the same difficulty wheel raised, giving thus a rocking motion which Mr. Locke found to belong to it when with respect to the placing of the blocks to the carriages, the effect of which was ren- whole. Now, although I am ready to grant opposite to each other, as was found in the dered remarkably obvious by the little in-| that the bar was actually weakened, and case of the fish-bellied rail. It seems posstrument employed. No doubt much of that this apparent anomaly is attributable to sible to avoid it in either case by making this is due to a want of parallelism in the the imperfection of the press, yet, on the the bearing places half an inch longer than bearing blocks; and therefore, as one step other hand, it must be admitted that it could, || the width of the chair. The reason given towards correction, I would recommend it with such a result, have lost but little of its by some for preferring the fish-bellied rail, to be made a special instruction, that the strength, and that the iron thus abstracted," that its weak neck allows it to follow a blocks shall in every case be placed immedi- viz. nearly į of the whole section, if judi- sinking chair,” is certainly a curious speciately opposite to each other, which, in pa- ciously introduced elsewhere, would un- men of engineering sagacity. The further rallel rails, may always be effected without doubtedly give a much stronger rail.” observations on the best form of chair deexpense or inconvenience.

Other correc While we fully admit the importance of|| serve careful attention. tions, however, are necessary, which will be these remarks, we imagine they will require The section on the formation of the noticed in their proper places."

further illustration before they obtain gene- joints” opens very curiously : Another branch of the subject is the ral assent. What is the longitudinal form “ On carefully examining the joints of length of bearing, and the consequent inqui-| assumed by the extreme lateral fibres sup- the rails on the Liverpool and Manchester ries as to the sectional dimensions of the posed to be so nearly ineffectual? If it be line, I am disposed to estimate that about rail and stability of the blocks and chairs. || the same as that of their neighbor fibres to- one in six of the plain butt joints are as perAdopting the parallel rail, and rejecting the ward the centre, it has required force to ex-||fect as can well be desired, and that another double-headed one, Professor Barlow deter-tend them—if it be nearer a straight line, one in six are as bad as bad workmanship mines from experience that the head of the they have hindered to some amount the ex- and negligence can make them; the rerail ought not to have a less sectional area tension of their fellows. Mr. Barlow does maining two thirds varying in character bethan 21 inches, that is, it should not weigh| not hazard opinions lightly, and will proba-tween these two extremes.” less than 22; lbs. per yard, and that the en-bly, on some future occasion, give further Has this celebrated road produced its tire depth must not exceed 5 inches. Com- reasons for the conclusion at which he has splendid effects, while one half of its power mencing with these assumptions, he gives arrived.

has been wasted, and its cost of repair plans, computations, and tables for rails In testing the stability of the blocks, the doubled by bad workmanship and negliwith bearings of the lengths of 3 feet, 3 feetdeflectometer again did good service. gence ?" What may not be hoped for 9 inches, 4, 5, and 6 feet, the sections being Though no great exactness was attained, it when searching inquiries like the present so arranged as to give the maximum appeared that blocks, five feet asunder, sunk shall have brought up railway furniture even strength.

as little under a passing load as those but to the present standard of decent workmanIn discussing the best sectional form of three feet apart. Considerable difference ship? rail, Mr. Barlow makes an observation well of opinion seems to exist, as to the econo After urging the necessity and attainableworthy of remark :

my and propriety on other grounds, of the ness of much greater accuracy, and stating “ In the sections given in a preceding use of more or fewer blocks. The argu-that government work is much better done, ings

, it will be seen that I have confined the which seem to show that the Professor'sh. In the smaller shells, which are still breadth of the lower web to 15, or, at most, help was by no means superfluous. He considerably larger than the opening in a to lị, inches, and this has been done, al gives his own opinion in these words : railway chair, and unquestionably much though I am well aware that, to extend the “ The conclusion to which I am brought, more difficult to cast, not more than a debreadth of the lower web, and to reduce its as to the relative expense of maintenanceviation of sự th of an inch is allowed, and depth, would theoretically give the strongest per block in five feet and three feet bear- I can see no reason why the railway chairs rail; in fact that the double T is, on paper,ings, or, more generally, in long and short and the end of the rails, should not be suba stronger rail than the deep and less broad bearings, after well weighing all these points, mitted to at least as close a gauge. To flanched rail, but I am quite convinced it is is, first, that in embankments, and where enforce this accuracy, may perhaps incur not so in practice. The lower web comes there is a soft sub-soil, the expense would some present charge, but do not the wear no other way into use than as it is brought be greater at first with the long bearings and tear of the rails and engines incur a into a state of tension by the action of the than with the short, but that it would ulti-|| much larger constant expense of maintecentre rib; and although the fibres of the mately become the same, although certainly nance ? I am sure it is unnecessary for me lower web lying immediately below the cen- never less ; and, secondly, that on rocky, to urge this point upon those proprietors tre rib are brought into action by it, andor very solid bottoms, the expense would who witnessed, during the experiments, the that these fibres excite a similar action la- be very nearly the same from tirst to last.”|| concussion on the rail exhibited by the deterally in those immediately contiguous to It can scarcely be doubted, that, while flectomer, which, of course, produced a them, and these again to the next, and so the earthern surface on which the block light concussion on the engine and carriaon, yet in a ductile metal, like malleable rests is new, it will be a little compressed ges. The whole of these were, doubtless, iron, this lateral effect is soon lost; so that permanently by every blow, and the number due to irregularities, of which the want of the extreme fibres of the extended lower of blows being as the distance between parallelism of the blocks and bad joints flanch become inefficient.

block and block, it will be sooner compress-were the principal. Some persons present “To convince Mr. Locke and some oth-ed under long than short bearings ; but, as attributed them in part to flat places in the er gentlemen of the weakness of the double soon as it has become so hard as to return wheel ; but if there are flat places in the T form, I had one of the rails taken up, to its shape after the greatest blows to which circumference of the wheel, to what are these and 1 an inch cut away on each side from it is liable, it is of litile importance how of attributable but to bad oints? To be conthe lower flanch, reducing its breadth at the ten it is struck; that is, whether the bear-|| vinced of this we have only to consider point of greatest strain, that is, in the mid- | ings be long or short.

what must be the effect of a blow on a wheel dle of the bar, to if instead of 24 inches. The form of chair he prefers is one which supporting a load of 3 tons, and moving

with a velocity of 30 or 32 miles per hour, || dimensions of the rails and chairs, and versed by a locomotive engine, and its train when such a body meets the end of a rail greater attention paid to the parallelism of of a gross weight of one hundred tonşo rising i, or, perhaps, nearly of an inch the blocks, and to a proper adjustment of the The experience of the Liverpool and Manabove another ; or when the joints are so distances of the ends of the rails from each chester Railway has shown that the average open as to allow the wheel to fall from one other to allow for expansion and contraction.” consumption of coke is considerably less upon the other, with all the impetus due to Some important theoretical investigations than half a pound per ton for each mile it such velocity.

follow the Report

, which we cannot notice is carried on a railway ; but taking the con“In order to arrive at some estimate of at present, further than to extract two im- sumption at half a pound, the whole weight this effect, a bad or open joint was select portant conclusions.

of one hundred tons will require the coned, the deflectometer applied to the block, It is found, " that the sum of all the va- || sumption of 50 lbs. of coke. It may be and the shock measured by the instrument. || riable resistances to a load by the deflection calculated that every 10 lbs. of coke will The rail was then taken up and relaid, so of the bar over which it passes, is exactly evaporate a cubic foot of water ; so that as to make the joint as close as usual, half the resistance the load would experi- the whole 50 lbs. will convert into steam 5 leaving the opening at the other end, andence in ascending a plane of the same half cubic feet of water in the distance of 1 the effect was again taken, when it was length, and whose height is equal to the mile. Now to convert into steam 1 cubic found that the bad joint increased the force central deflection of the same bar." foot of water, requires 1,950, or say 2,000 of concussion full 50 per cent. ; that is, From the table-page 88, it seems that|cubic feet of air, then 5 feet of water will the engine had to sustain a shock from this the increase of power required by the de- of course require 10,000 feet; and this will circumstance one-half at least greater Pections of the bars, is nearly proportionate be the whole amount of contaminated air than was due to a very common joint, and to the distance of the blocks; a fact which in one mile in length of tunnel. To deterprobably double what it would have had to is certainly to be taken into account when mine the proportion of such an amount of sustain at a good one.”

determining the length of bearing. foul air, and the whole air contained in the Thus we may add, that the same care The appendix details many experiments tunnel

, we may take for example a modewhich is required by the "scarcely-percep- not given in the body of the Report. rate sized tunnel 30 feet high, and having tible” but important curve in the bottom of The whole forms a very valuable contri-|| an area of 800 feet. One mile in length of Mr. Locke's chairs (p. 55) would certainly || bution to our knowledge on some of the such a tunnel will contain 4,224,000 cubic produce much better articles than those most important subjects connected with the feet; hence the contaminated air will bear described as in use on the Liverpool and construction and management of railways. to the whole quantity in the tunnel the ratio Manchester line.

We cannot but hope, that the same profound of 10,000 to 4,224,000; or it will be as I The following is the summary which the mathematician and veteran experimentalist to 422. It will scarcely after this appear Professor gives of his Report :

will be again engaged, in illustrating the that any valid objection to tummels, to assert " Ist. I am of opinion, that as far as is theory and correcting the practice of this that an injurious effect must result from the consistent with the amount of the first out-|| most influential of recent inventions.

contaminated air, when we find that the lay, it is desirable to increase the weight or

quantity of this description of air, produced section of the rails, and to decrease pro

RAILWAY TUNNELS.

by the passing of the whole train, will be portionally the number of bearing blocks. || (From Mr Gibb's Report upon the several proposed no more than a part of the whole quantity * 2d. That in cuttings and other places

Lines for a Brighton Railway )

in the tunnel. furnishing a good firm bearing, the present An objection has been made generally Let us then venture to hope, that any size of blocks is sufficient ; viz. allowing to all tunnels-namely, that the air con- prejudices which may now exist against the for the intermediate blocks four feet, and|tained in them will be so contaminated by construction of tunnels upon railways will for joint blocks five feet, while the bearing the noxious gas produced by the locomo- be dispelled; when we find that no injurious length does not exceed five feet ; but that tive engines in passing through them, as to

consequences will ever result from the foul. on embankments they will probably require render it unfit for respiration. Whether air, or any other of the numerous evils which to be proportionally increased in size. But this objection has ever been advanced, or have been so forcibly dwelt upon by those I recommend this to be put to the test of at all supported, by any scientific man pos- who affect to perceive the most unhappy actual experiment.

sessing sufficient chemical knowledge to consequences from their adoption.—[Lon“ 3d. I am of opinion that the cost of enable him to judge correctly on the sub-don Mechanics' Magazine.] maintenance will, in the former case, afterject, is doubtful. The probability, howa short time, be in proportion to the reduced ever, is, that the fear of any injurious effects number of blocks, but certainly not less. from foul air has originated in those who Kits puhl copper mine in the Tyrol Feet. " 4th. I consider the double and equal have witnessed the effects produced by mountains,

2764 flanched rail to be inferior, in strength and steam engines in passing through the small Sampson mine at Andreasberg, in the convenience of fixing, to that which is de- tunnels on some of our canals ; and if they Hartz,

2230 scribed and modified to suit different dis-have for a moment imagined that any sim- Valencia mine, (silver,) Guanaxuato, tances, in a preceding page. ilarity will be found in the effects in the

Mexico,

2170 “ 5th. I consider Mr. Sinclair's proposi- two cases, their fears are quite justifiable. Pearce's shaft, (copper,) consolidated tion for rendering the rail plane at its points The tunnels on canals are commonly con mines, Cornwall, of bearing, to be in every respect recom-|| structed of such limited dimensions, that it Monkwearmouth colliery, Durham, mendable.

would be highly dangerous to attempt the Wheal Abraham mine, Cornwall, 1410 "6th. I am of opinion the form of chair, same application of steam power as will be Eiton mine, Staffordshire,

1380 and method of fixing the rail in the chair, necessary on a railway; for instance, in The deep mines in the Tyrol, Hartz and proposed by Mr. Stephenson, is as simple the tunnel constructed by Mr. Telford; on Andes, above described, are all in high sitand efficient (adopting the plan of rolling the Hare Castle Canal, the area above the uations—the bottom of the Mexican mine of Mr. Sinclair) as can be desired. water in the canal is only about one hun- lis six thousand feet higher than the top of

" 7th. Yielding, as I am always ready to dred feet ; and even the Thames and Med- the Cornwall shaft. The deepest perforado, to practical opinions, when they are way in transverse dimensions, perhaps the tion beneath the level of the sea, and confound pretty generally to agree, I am dis- largest canal tunnel in England, has only sequently the nearest approach to the earth's posed to think the present mode of fixing an area of four hundred and fifty feet; while centre, has been made at the Monkwearthe chairs to the blocks, with a wooden the smallest tunnel contemplated on the mouth colliery, which is fifteen hundred and plug and iron pin, is, from its simplicity Brighton Railway, will have an area of at thirteen feet below the surface of the Gera and convenience, the most recoinmendable. least six hundred feet.

man ocean. Pearce's shaft (thirteen hun“Lastly. I am strongly convinced that In order to explain to what extent the airdred and thirty-eight feet below the level of no change or modification of form will pro- in a tunnel is contaminated by a locomo- the sea,) was, until lately, the deepest in duce ang essential improvement,

till greater tive engine passing through it, let us sup- the world.-(Geology in 1835, (Mining uniformity be enforced in the figure and pose a tunnel one mile in length to be tra- Review.)]

DEPTH OF MINES.

1650 1600

« iepriekšējāTurpināt »