1849. I 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



193 



RAILWAYS' PERMANENT WAY. 



{With Two Engravings, Plates X. and XI.) 



Report on the Construction of Permanent Way. By Robert B. 

 DocKRAY, Esq. (By order of the London and Nortli- Western 

 Railway Company.) 



To THE Committee of AVay and Works. 

 Gentlemen — In accordance with j'our directions, that I should 

 examine and report to you upon tlie permanent way as laid down 

 by Sir John IMacneill, upon the Dublin and Drogheda and Great 

 Southern and Western of Ireland Railvrays, I went to Dublin on 

 the 20th ultimo, and remained there until the 26th, and in the 

 interval travelled several times over portions of the lines, as well 

 as of others terminating in that city, and I carefully examined all 

 the details of construction. 



Sir John Macniell very handsomely gave me all the information 

 I required, and was at some pains to explain tlie principles which 

 have governed him in adopting the peculiar construction which he 

 has introduced. 



In laying before you the following remarks, I have thought it 

 desirable to extend my observations to the construction of perma- 

 nent way generally, with the view of determining the best mode ot 

 can-ying out the renewals upon the Southern Division of your rail- 

 way, which have become necessary at a period of time earlier than 

 I had anticipated, consequent upon the comparatively new circum- 

 stances of the great increase not only in the weight, but in the 

 speed of the engines. 



I would here remark, that when competition was developing the 

 present high velocities upon railways generally, Mr. Robert Ste- 

 phenson gave it in evidence as his opinion, that the limit would be 

 found not in any particular gauge, or in the evaporating power of 

 the engines, but in the economic endurance of the permanent way 

 to bear the additional weight which must, as a matter of necessity, 

 accompany every increase of speed. Time is. in my opinion, ra- 

 pidly demonstrating the truth of this observation. Every new 

 class of engine which appears, surpasses its predecessor in power 

 and in speed; and it is evident from the large size of some of 

 those about to run upon your line, that at any rate the builders do 

 not consider that they have as yet reached the limit of their scale. 

 The rapid deterioration of the permanent way, however, about 

 which there can be no doubt, raises the question whether the 

 speeds already attained have not approached the economic limit to 

 which Mr. Robert Stephenson refers. If this be the case, railway 

 companies must look to a considerably increased outlay in the 

 shape of renewals of permanent way. It may be financially dis- 

 guised for a time, but sooner or later it must be met as a regu- 

 lai'ly-recurring charge. 



I have no doubt that the wear and tear of the carrying stock is 

 also increased in a high ratio witli the speed, and I do not see why 

 the public are to reap the whole advantage, leaving the railway 

 company the burden of the additional cost. Means should be 

 taken by the railway body generally to raise the express fares, 

 and thus in some measure to share the benefit with the public. 



Returning to the construction of the road, it is evident that in 

 all renewals, increased weight of rails, and increased dimensions 

 of the materials generally, must be adopted to meet the increased 

 duty required. It is of great importance in re-construction, that 

 we should ascertain the weak and defective j)oints : witli this view 

 I have carefully inspected many portions of the line, and have 

 availed myself of the knowledge of the experienced overlookers 

 who have been in your service since the commencement of the 

 works. 



I find, as a general result, that stone blocks are not adapted to 

 high speeds, — they are rigid, the chairs cannot be retained firmly 

 upon them, and from this cause they are subject to rapid wear; 

 and as they are in this district very expensive in first cost, I should 

 recommend their being renewed with sleepers. 



Wherever the stratum under the formation line (the bottom of 

 the ballast) is sound and hard, and there is a sufficiency of ballast, 

 the wear and tear of the road is confined, for several years, to 

 sim|)le renewals of keys, — until, in fact, the rails begin' to split 

 and laminate, under the action of the trains. This "period will 

 vary with the traffic: in ordinary cases I estimate it at from 15 to 

 20 years. There are still many years' wear in the rails laid down 

 at the northern end of this division of the line. Under this head 

 I should class the permanent way of the railways wliich are laid 

 upon the older geological formations, especially those I saw in 

 Ireland, where the substratum is almost universally of the very 

 best description for railway works. M'hen. however, works are 

 constructed in the clays of tlie tertiary and some of the secondary 



No. 142.— Vol. XII.— July, 1849. 



formations — all of wliich are highly susceptible to the action of 

 water — the expense of maintaining permanent way is much en- 

 hanced. 



The lapse of time in developing the action of water upon the 

 clays, shows itself in a gi-adual softening of the substratum, so 

 that it no longer presents an uniform surface under the ballast, 

 but protrudes itself upwards, — and gradually mixing with the bal- 

 last, so far deteriorates its quality, as to render it soft and non- 

 resisting. In this state, the ballast slides into the railway ditches, 

 carrying the road with it, so as to require constant care in cor- 

 rectly maintaining the gauge. In all such cases the blocks must 

 be removed, and replaced with sleepers. Another evil is, that in 

 ballast so deteriorated no repairs can be executed except in fine 

 dry weather ; it presents no resistance to the beaters, and conse- 

 quently the defective bearings cannot be raised by any ordinary 

 process of repair — to open out such road in bad weather only 

 increases the evil. The remedy for this defect is to lift the road, 

 wlierever practicable, and add a few inches of good fresh ballast. 



Permanent way laid upon a substratum as above described, is 

 subject to much more rapid wear than in the case previously men- 

 tioned ; the soft yielding nature of the bottom permits so much 

 movement amongst the parts, that they soon loose their fit, the 

 rails become injured at tlie joints, the chairs are worn, and the 

 keys require constant renewal. 



6n the Southern Division of this line we have many miles of 

 sucli road — in fact, with the exception of the chalk district, there 

 is lery little sound material south of Rugby. 



AYith tlie view of bringing before you the whole subject, I have 

 prepared a set of drawings of permanent way as laid down on 

 various lines of railway, selecting those which I consider best of 

 their kinds ; they are as follows : — 



1st, The mode adopted bv Mr. Robert Stephenson. (Drawings 

 No. 1 and 2.) 



2nd, That of Mr. Brunei. (Drawing No. 3.) 



3rd, That of Mr. Hemans, on the iSIidland Great Western of 

 Ireland. (Drawing No. 4.) 



4th, That of Sir John Macniell, on various Irish lines of rail- 

 way. (Drawing No. 5.) 



Mr. Robert Stephenson's 3Iethoil. — (Druunnjs A'oi. 1 and 2. J 



These drawings represent the permanent way on the London 

 and North- Western Railway, No. 1 being with a rail 75 lb. in 

 weight per yard, and No. 2" with a rail of 82 lb. per yard. The 

 latter shows the improvements recently introduced in the form of 

 the rail, increased weight of chair, &c. 



The cost of 5 yards of single line of No. 1 is SI. lis. 5d. 



The cost of 5 yards of single line of No. 2 is 61. 5s. Oid. 



Tlie number of parts in the same length of No. 1 is 47 



The number of parts in the same length of No. 2 is 49 



— (For further details, see Appendix.) 



The bearings are transverse sleepers, placed 3 feet apart on the 

 average. 



This mode of construction is that generally adopted on the nar- 

 row gauge lines of railway. The cross sleepers possess many ad- 

 vantages ; they secure the accuracy of the gauge and of the cant 

 of the rail ; tliey afford great facilities for surface drainage, and 

 any repairs or renewals are readily executed ; they also at once 

 show, by the working of the ballast, when and where the road is 

 out of order, affording certain indications to the workmen where 

 their attention is required. 



The weak point is at the joints of the rails : most engineers en- 

 deavour to remedy this defect by drawing the sleepers nearer 

 together at the joints, and by selecting the largest sleepers for 

 this bearing. To a certain extent, this is found to answer the 

 purposes, but it is apt to disturb the uniformity of the bearing 

 surface on the ballast, a point which I am inclined to think is of 

 some importance, as affecting the steadiness of the motion of the 

 trains. 



Mr. I. K. Brunei's Method.— ( Drawing No. 3.J 



This drawing is taken from the jiermanent way of the Chelten- 

 ham and Great AYestern Union Railway, at Gloucester, and which 

 I was informed embraced all the last improvements introduced by 

 Mr. Brunei. 



The weight of the rail is 72 lb. per yard. 



The cost of 5 yards of single line of railway is 6/. 14s. 54rf. 



The number of parts in the same length of road is 81. 

 — (see Appendix.) 



The bearings are longitudinal timbers, with a transome at every 

 15 feet apart, to retain the gauge. Thin pieces of wood are laid 

 across the timber bearing, and upon these the bridge rail is laid : 



2; 



