On the Wear of Steel Rails.1

(Report of the Società Italiana per le Strade ferrate meridionali: Rete Adriatica.)

The observations embodied in this report were made on six different types of rails, sections and dimensions of which are fully given in the text. The present normal type weighs from 72 lbs. to 74 lbs. per yard; but some sections are in use weighing 55 lbs. and 42 lbs. per yard.

Apart from fractures, the life of rails varies very considerably on different lines and at different parts of the same lines; depending mainly upon the curves and gradients, on the traffic, and on the extent of exposure to atmospheric influence in tunnels or in open portions of the line.

The chief causes of failure of steel rails may be thus stated: (a) Fractures; (b) wear of the upper surface by the abrasive action of the wheels; (c) wear of the lower surface, chiefly by oxidising or corrosive agency; (d) deformation and wear of rails and fastenings at junctions of rail-lengths.

The most usual cause of fracture of a rail is some defect in the metal. From the 1st July, 1885, to the 31st December, 1896, the total number of fractures recorded on the company's lines was: between the 1st October and the 31st March, 529; between the 1st April and the 30th September, 265; i.e., there were just twice as many fractures during the colder period as during the summer months.

The wear of the upper surface of the rail is, probably, the source of failure most readily assignable to known factors and definite rules. The statistics of this wear are scheduled in tabular form in the report; the following instances are selected from different lines, gradients, and positions quoted :

It is noted that the heaviest wear occurs near signals and

1 Minutes of Proceedings Inst. C.E., vol. cxxx. p. 354.

stations, where the action of brakes is evident in the additional friction and abrasion.

A selection of summary results from various lines is quoted in the subjoined extract from the next series of Tables :

-

The general conclusions to be deduced from these observations are: (1) That the wear of the upper surface of the rails increases rapidly with the increase of gradient; (2) that tunnels greatly influence the wear of the under surface of the rails, the rate of deterioration being about twice as rapid as where the rails are in the open.

This rapid deterioration, due to oxidising or corrosive action, is caused by the constant moisture in the tunnels, to the corrosive nature of the gaseous products of combustion, and to emanations from the soil. On account of these special causes of deterioration of the metal, the mere extent of abrasion in the head or top flange of the rail is an absolutely insufficient criterion for the determination of its life. Many rails, the wear of whose upper surface is still far from the maximum limit prescribed as necessitating renewal, have moments of resistance inferior to that of rails which have arrived at that limit. This conclusion is demonstrated by sections and particulars of rails from the Trabocco tunnel on the Bologna and Otranto line, and the Piteccio tunnel on the Bologna and Pistoia line.

A description is given of the Trochitomograph-an apparatus specially designed for delineating rail-sections. The frame, which is rigidly clamped on the rail, carries delicately but firmly adjusted equal and parallel arms on each side, with double points at each end. As one point traces the outline of the rail the other point necessarily follows absolutely every inequality, and records the outline on the paper secured on the frame.

The railway company has not made trial of any special varnishes or protective coverings for rails, not believing in their permanent utility, as they must necessarily get worn away at the surfaces of contact-precisely where most required. If, however, any coating is to be applied, it should be done directly the rails leave the rolling-mills.

The junctions of rail-ends constitute the weak point of permanent

way.

The deflection and deformation of the rail-ends is often very marked, amounting in some cases to almost inch. Experiments have been made with the object of securing sufficient rigidity for the junctions, by bringing the end sleepers nearer together-from 24 inches to 20 inches apart-and by substituting an external check rail for the ordinary fish-plate. These have, however, not had a sufficiently lengthy trial to enable reliable results to be stated. It must be noted in this connection that where the gauge is eased, as on curves, the whole weight of the engine or carriage may, especially if the tires be unevenly worn, come upon the rail-end joint.

On the Florence and Pistoia line, with rails of the North Italian type, the end sleepers are spaced at 15 inches centre to centre. A rigid tongue with packing-rail stiffener has also been fitted; but it is cumbersome and complicated, and introduces liability to extra wear. A double-width sleeper (17 inches) has been proposed, so as to take two chairs at 10 inches centres, constituting practically fixed ends, while leaving a sufficient degree of elasticity to the respective rails. These several methods. of dealing with the case are illustrated and described in detail. The following conclusions are stated as summarising the experience of the company as set forth in the report:

(1) Fractures of rails are generally due to defects in the metal. The normal proportion of such failures is about 1 in 2,000 per annum. If above this rate, some abnormal conditions of quality or of local circumstances must be looked for.

(2) The wear of the upper surface of the rail is least where the line is open, straight or on easy curves and fairly level. The rate of wear increases rapidly in tunnels.

(3) The extent of wear alone is not sufficient to determine the presumptive life of a rail, as corrosive action must also be taken into consideration.

P. W. B.

The Railways of the World.

(Archiv für Post und Telegraphie, 1898, p. 470.)

This Paper gives an analysis of the present state of the railways in the world, with Tables showing the rate of development of the lines in the various countries and the ratios of length of line to the area of the country traversed and to the number of the population served.

One Table shows the length of railways on the five continents, from which it appears that in the year 1896 Europe had 159,723 miles, America 232,714 miles, Asia 28,493 miles, Africa 9,189 miles, and Australia 13,893 miles. The increase in length between the years 1893 and 1896 was lowest in America with 3.9 per cent., and greatest in Africa with 19.5 per cent. A detailed

Table follows, showing the distribution of railways in European countries, from which it appears that Norway was lowest with only 0.08 mile per square mile of territory, and Belgium the highest with 0.31 mile per square mile of territory, while the ratio of length to population was lowest in Servia with 1 mile per 10,000 inhabitants, and highest in Sweden with 123 miles per 10,000 inhabitants.

E. R. D.

Extension of the Paris Eastern Railway Station. A. DA CUNHA. (La Nature, 5 November, 1898, p. 358.)

Nearly all the great railway companies which have their termini in Paris are making special preparations for the Exhibition of 1900. In addition to its main line traffic, the Eastern Railway Company has an important suburban district to provide for. The number of passengers carried has risen in 10 years from 7 millions to 12 millions per annum, and yet its station is one of the smallest and most ill-designed in Paris. By reference to plans the Author describes the improvements about to be effected, which, while they will not greatly alter the departure platforms and the booking offices, will entirely re-model the arrival side of the station. It is proposed to carry out these works in two sections, with an interval of a year between them. Those alterations which are considered most urgent will be put in hand so as to be completed in time for the Exhibition in 1900, and then, after a twelvemonths' delay, the works will be resumed, and the entire alteration will be carried through. The Author states briefly the conditions which engineers now consider to be indispensable in designing an important station, and he explains how it is proposed to comply with them in the present case. A series of plans indicate: (1) the existing station, (2) the changes to be carried out for the year 1900, and (3) the design to be ultimately realised. An illustration is given to explain the works in progress, and an elevation shows the station as it will be when all is finished. The cost of the buildings to be demolished will alone involve an outlay of over half a million.

G. R. R.

The Prolongation of the Orleans Railway to the Quai d'Orsay.

L. BACLE.

(La Nature, 1 October, 1898, p. 278.)

It is pointed out that the constant increase in the traffic and the needs of further accommodation have in turn compelled each of the chief railway companies having termini in Paris to re

model and extend their stations. Among others the Orleans Company has been for some time considering this question. For certain portions of the traffic the removal of the station for Sceaux from the Place Denfert to the Luxembourg, which took place in 1895, has effected all that was needed, and the results of this alteration, which entailed the construction of 1,640 yards of line, have proved in every way successful, and have led to an increase in the first year of 40 per cent. in the traffic. It has subsequently been decided to transfer the whole of the main station to the site on the banks of the Seine, occupied till recently by the ruins of the Cour des Comptes. The Orsay barracks, which are also being removed, rendered additional land in the vicinity available, and the negotiations with the Government for the purchase of the property were satisfactorily completed in 1897. The projected railway will consist of the prolongation of the two central lines of the existing station, which will start with a sharp decline towards the River Seine 481 yards in length under the Place Valhubert, and proceed from thence to the banks of the river, which will be reached at the Quai St. Bernard. The railway then passes alongside the river under the quays for a length of 710 yards to the Sully Bridge. Side openings facing on to the river will be pierced for light and ventilation. The level of the rails is approximately that of the ordinary water-level of the Seine. All the works will be executed as far as possible by means of tunnelling, in order not to interfere with the surface traffic. Plans are given of the station and elevations of the principal fronts towards the river and towards the Rue de Bellechasse, which latter frontage will be occupied by a terminus hotel. The booking-offices will be arranged on the level of the street, the platforms, 16 4 feet below, being reached by staircases and lifts. The station proper will cover a rectangular site of about 218 yards by 82 yards, and will contain fifteen lines of rails. As this station occupies one of the finest sites in Paris, in close proximity to the Tuileries Palace and to the Palace of the Légion d'honneur, it has been necessary to study the architectural details with great care, and this portion of the work has been entrusted to Mr. Laloux. A detail section is appended, in order to explain the construction of the principal tunnel and of the tunnel openings along the banks of the Seine.

1 Minutes of Proceedings Inst. C.E., vol. cxxiv. p. 473.

G. R. R.

2 D

[THE INST. C.E. VOL. CXXXV.]