52

Harlem Railroad Receipts.-Concentric Steam Engine.

In the bridges now described, no spikes are used to fix down the planks, but the planks are held in their places by two flat rods extending the whole length of the planking. The author then describes in detail, by reference to the drawing accompanying the communication, the peculiar method of construction which he has adoptel. The planks are five-eigths of an inch apart, so that dirt and wet may not lodge in the joints. The bridge is balanced by two stones hung at the ends of the swing poles of about 6 cwt. each. The four principal carriers are supported by three cast-iron bearers fixed to a grooved circle, which rests on cast-iron balls, running in another grooved circle. By this construction no planks are pierced with spikes; the box of stones is got rid of, and a free access of air is obtained; and the peculiar causes of destruction to which turnbridges are exposed, are it is conceived in a great measure obviated.—Transactions of the Institu tion of Civil Engineers.

$3,819 32

RECEIPTS ON THE HARLEM RAILROAD.-Fare for passengers for December, 1838, do. 1839, 5,108 02 Showing an increase the last month of $1,288 70 over the corresponding month of the previous year, equal to 33 per cent.

The receipts on this road for the last three years are as follows, viz:— Fare from January 1st, to December 31st, 1837,

do. do.

do.
do.

do. do.

do.

do.

1838,

1839,

55,622 18

79,794 74

99,811 23

The increase of receipts, comparing 1838 with 1837, is $24,172 56, or 44 per cent, and of 1839, compared with 1838, is $20,006 49, equal to 25 per cent. increase.

This statement exhibits conclusive proof of the growing usefulness to the public, of this road.

It is in fact but the first link in the main chain of that mighty and measureless system of internal communication, which, connecting with the N. York and Albany railroad, commencing by its charter, at the termination of the Harlem railroad, and branching throughout our State, throughout New England, and to the whole interior of the Great West, will be rendering those immense inlaid communities tributary to this State and its metropolis.

It is even quite evident that railroads are destined to produce as great a revolution in the conveyance of passengers on the land, as steamboats have done on the water.

BUNNETT AND CORPE'S CONCENTRIC STEAM ENGINE.

Sir. In theletter of your correspondent (Mr. Macdonald) relative to our patent Concentric Steam Engine which appeared in your last number, the conclusions he has drawn are so erroneous, that we shall feel obliged by your insertion of this in the following number.While he admits that the result of the trials of the modes of applying the power by the tables published in your former numbers, which shows a gain of more than two to one, are correct, and might naturally have been expected, he asserts that one main feature in the case has been overlooked, viz., that the consumption of steam is equal to the power gained; this is quite at variance with the fact, as we shall endeavor to show. We have now just completed a high pressure engine on the concentric principle, the piston of which is 12 inches broad and 8 inches deep, containing 96 square inches, the crank throw is 9 inches, the stroke consequently 18 inches, the outer curve of steam chamber, an arc of a circle, 2 feet 4 inches in diame

ter, the inner curve 1 foot diameter. Now supposing this chamber to be completely filled with steam at each stroke, allowing for the concentric form, it would contain 1872 cubic inches. A cylinder on the vertical or horizontal principle of the same area of piston would require 1728 cubic inches to fill it, (which is the extent of the difference, as any increase of the radius of curve tends to reduce it.) just one-twelfth less than the concentric engine, whose gain of power by its direct application, as shown by the tables, he does not dispute. This is supposing that all the steam it is possible to admit, is thrown into the cylinder at each stroke of the piston, but it is admitted by most engineers that all the steam thrown into the cylinder after the piston has completed two-thirds of its stroke is useless and detrimental, by the arrangement of our slide valves, we effectually cut off the steam at two-thirds of the stroke, which cannot be effected by the present locomotive engines with the single slide, therefore taking one-third from 1872, the quantity of steam we should actually use in the concentric engine at each stroke of the piston would be 1248 cubic inches, considerably more than less than the present engines, to say nothing of waste by exhausting the steam in the passages, which we entirely avoid. It is, we conceive, no fault in our concentric engine, that it does not differ in principle from the best engines of the day. We have only sought by new forms and combinations to get a more direct application and consequent increase of power; how far we have succeeded, we shall shortly be enabled to show by an engine of about 10 horse power that we are erecting on our premises at Deptford, for the purpose of testing its power, consumption of fuel, etc. Pending that trial it was not our intention of troubling you or your readers with any communication on the subject, but (adopting your correspondent's words.) we are inclined to believe that the appearance of this letter may be useful at least to us, in counteracting whatever erroneous views may have been formed by the perusal of your correspondent's communication. We remain Sir, your obedient servants,

64

BUNNETT & CORPE.

OBSERVATIONS ON THE PRESENT MODE OF EXECUTING RAILWAYS, WITH SUGGESTIONS FOR A MORE ECONOMICAL, YET EQUALLY EF

FICIENT SYSTEM, OF BOTH EXECUTING AND WORKING THEM." By Francis Wishaw, M. Inst. C. E.

The author at the commencement of this paper alludes to the principal causes of the great differences between the original estimate and cost of railways. Among these he enumerates the imperfect knowledge of the strata, which occasions the cuttings and embankments to be formed with slopes, which are dangerous, and add to their cost-the imperfect formation of the embankments. especially in clayey soils, which in the opinion of the author ought to be carried up in layers or courses of from 1 to 2 yards in thickness, sufficient time being allowed for subsidence before the next layer is added the cost of stations, which in some of the great lines forms a considerable proportion of the whole cost.

The author then proceeds to suggest means for effecting a considerable saving in the original cost of railways, a certain method of preventing accidents by collision, a saving in the annual expenditure, and a better adaptation of the locomotive engine to its work.

With these views, he proposes a single line of rails-that the line should be divided with intermediate engine stations, three on the London and Birmingham for instance, the engines at each being suited to the prevailing gradient of the district. Thus a line of railway may be more easily

laid out, as one or two unfavorable inclines will not affect the working of the whole. At each station there must be a small portion of an additional line of rails, and also at other convenient intervals. The mode of working such line is as follows:-Engines are to start simultaneously in each direction from the terminal and intermediate stations. These engines will pass each other at one of the portions of the double line, and the engine being reversed and taking the other train, will return to the station from whence it started, when another exchange of trains takes place. Thus there is a regular interchange of loads throughout the day, and each engine is confined to its own portion of the line, and it is impossible that a collision can take place. Equal accommodation would be afforded to the public, and the engine-man, from being always confined to the same small portion of the line, would be perfectly conversant with every part of it. The saving which would on this system be effected on the original cost is estimated at more than 5000/ per mile.-Trans. Ins. C. E.

WESTERN AND ATLANTIC RAILROAD.-The committee on internal improvement in the Georgia legislature, have reported strongly in favor of the State's completing the Western and Atlantic railroad to Ross' Landing on the Tennessee river. The cost thus far to the State, has been $1,614,357. It is estimated that the work may be completed for $559,705, for which the contractors are willing to receive the State bonds in payment.

The committee also recommend the adoption of a resolution granting to the Hiwassee railroad company the privilege of extending their railroad into the territory of Georgia, with the fullest permission to said company to select their own route and point of connection with the Western and Atlantic railway. If we mistake not, a resolution was adopted at the last session of the Georgia legislature pledging the faith of the State to construct a branch connecting the two roads. The distance would be only about fifteen miles.-Nashville, (Ten.) Banner.

RAILWAYS.

Few works on the subject of railroads have been published, which enter so much into the necessary and important detail of the construction and management of that species of public work, than the one now before us by Lieut. Peter Lecount, R. N.

The necessity has long been felt for a well digested work upon those subjects, which the merest tyro in the profession immediately recognizes as desiderata in the usual treatises upon such subjects. The present volume, though nominally a reprint of an article in the Encyclopedia Brittianica, is much enriched by additions upon the most inportant topics. We shal! from time to time give our readers selections from those portions of the work most novel in their character, and commence in the present number with an extract upon the subject of railroad accounts and statistics, together with the introduction of the work.

In treating of the construction and mode of working railways, we shall confine ourselves principally to those which are intended for the transit of passengers and goods, and which are now opening so vast a field for the improvement of the human race; an improvement, in fact, entering into all the relations between man and man, and which no one, be he ever so sanguine, can venture to fix a limit to.

From the middle of the seventeenth century various contrivances have been in use for decreasing friction on roads, particularly no ar the collieries in the north, such as laying down tracks of wood and stone for the wheels of wagons; it having been found that the much greater quantity of work performed by horses on these tracks, or, in other words, the less number of horses required to do a given portion of labor, more than repaid the expenses attendant on forming the tracks. These, in general, gave way to the flat or tram rail, made of iron; but the improvements were very slow, and at last were only applicable to certain circumscribed localities and materials for carriage.

Possessing little general interest, and cheifly benefiting individuals, the attention they attracted was principally confined to the parties immediately connected with them. But how different is the prospect now before us, since we have seen the magnifient creations of George Stephenson? Packhorses are still the only mode of transit for traffic in many parts of the world; and within seventy years this was the general mode of conveyance for the carrying trade to Yorkshire and Lancashire from the west of England and Birmingham. In the year 1830, when the London and Birming ham railway was projected, the expense of constructing it was stated at six thousand pounds per mile with one line of rails, which were to be worked by horses, and warranted to go eight miles an hour; now the public are complaining of going only twenty miles an hour, and we have a right to expect, that at no very distant period, this velocity will at least be doubled; in fact, at the rate improvements have been advancing for the last few years, we know not where to place a limit of increase in speed.

It is of these splendid creations that we have here to speak. We shall show the method of conducting a modern railway, from its earliest commencement, through all its various stages in each department, both in and out of doors, up to the period of its final completion; and shall end by explaining the method of setting it in full operation, pointing out, in each division of the labor, those modes of proceeding which will most conduce to a satisfactory result, and marking those things which practice has shown should be avoided; collecting the contrivances and appliances which have been found useful, from whatever source they may be derived, and setting a beacon upon shipwrecks, that they may become other men's landmarks.

At page 336 he says.- The last department which we shall describe is not the one of the least importance. It is that in which all the statistical details are wrought out; it deals in final quantities and prices, and in ratios. With the duties of this department, may be advantageously united the very essential branch of making and registering all experiments. The statistical details of railways are now becoming of such importance, that the government should undertake to publish them in a connected form. In the meantime, each company should, for their own sake, keep an exact register of them, to accompany their half-yearly reports. The Liverpool and Manchester company set an excellent example, in this respect, for several years and it is to be regretted they have not continued to issue these valuable docments, in order that the degree in which the expenses lessened as the road became consolidated, and the management of a new and unusual undertaking became better understood, might have been ascertained.

Nothing will tend more strongly to keep down the expenditure of railways than the free publication of these statistics; bad management must then become apparent, and the evil, once known, cannot fail to be remedied. It will be like the publication of the duty done by the steam engines in the Cornish mines; every one will be continually stimulated to keep pace with those companies who show themselves to be the most efficient in their busi

ness; and the relative value of the respective managers will become apparent. At present we have no statistics for long lines. This state of ignorance, it is hoped, will not continue.

Numberless experiments are yet required to determine the laws which should govern railway practice; and by far the greatest portion of these could be conducted with but little, if any expense, beyond that of a mere registration of passing facts; the value of others, again, would amply repay the outlay which would be necessary in order to make them. Railways have now been in operation eight years, yet we have no generally recognised constant quanties applicable to their daily practice; friction, cohesion, power, consumption of fuel and water, wear and tear, expense of principal and secondary stations, cost of management, and many other equally important items, are all variously stated and in part assumed; so that new undertakings are, to a great extent, laboring in the dark for want of receiving that assistance which would be in all cases beneficial to both givers and receivers.

This department should be in operation from the first commencement of the railway, and during its progress should be employed in keeping an exact account of the state of the respective works; the quantity and price of all materials used in the construction of the railway; comparing these with the estimates; comparing the work done with the time in which it ought to have been done; keeping detailed accounts of each of the articles composing the permanent way; testing all the rails as they are received, examining the merits of new inventions and improvements, and all other matters of a similar nature; but when the railway is opened, the most arduous duties will commence, and we are satisfied railway statistics will never be placed on a proper footing, till government undertakes the business, and issues out printed forms to be filled up by each company.

The statistical department should be a confidential one, and no person except the principal should be able to arrive at final results. These should embrace every branch of expenditure, and should be made out and registered every month, and printed every six months; being reduced, whenever it is possible, to the rate per passenger per mile, and per ton per mile respectively, for passengers and goods; with the reasons for any increase or decrease. This periodical statement would be a powerful incentive to economy, and at all times it would be seen, whether or not the money expended preserved its proper ratio with the work done.

The statements which should be shown by this department, would fall into two principal heads; first, the expenditure and receipts, under the head of passengers and goods, in all their details; and next, a classification of these details; those cases where the expenditure is of a general nature, being dealt with accordingly. For instance, the maintenance of the permanent way should be apportioned between the coaching and carrying departments, in the ratio of the weights carried by each of those departments and the relative velocities. The police, switchmen, gate keepers, general office establishment, rents taxes, interests on loans, &c.. should be apportioned according to the ratio of profit in each department, this ratio being taken exclusive of those items.

The details should show the expenditure in the coaching and carrying office establishments, guardes' wages, porters' wages, brakesmens' wages; expense of cartage, distinguishing horse keep; wages repairs, &c.; duty on passengers, gas, water, oil, grease, tarpaulins, ropes, slings, &c. ; for, in each case, the coaching and carrying departments separately. The general office disbursements, including direction, advertising, printing, law salaries, &c.; all given separately. The maintenance of way, including en