1842.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



3i3 



colliery wagon-ways were introiluced— the Professor observe-1, we are just 

 coming back to the original form and material as best ailaptcil for the pur- 

 poses of a railway— viz. timber laid longitudinally. When blocks of stone 

 are used to support the chair and rail, weight seems to be sought for as 

 desirable, and the general cubic contents of such blocks as are considered 

 proper for a good way are about five cubic feet— viz., 27 inches wide, and a 

 foot thick. When cross bearers of wood are the supports, each sleeper, as it 

 is termed, contains about two cub'c feet of timber, being about seven feet 

 long, with a transverse section of 40 square inches, being full eight inches 

 broad, and averaging live inches thick. The intervals at which the blocks or 

 sleepers are placed vary from three to five feet, according to the weight of 

 the rail or of the load. With these descriptions of supports, it becomes 

 generally necessary that a chair or saddle be attached thereto to receive the 

 rail, which is seldom fastened directly either on block or sleeper, without the 

 intervention of this contrivance of a chair, unless when the rail is made 

 wide and flat at the base. Such shaped rail is now much used on cross 

 bearers of wood for temporary railways, by contraclors. while e.xecuimg 

 works. Mr. Vignoles said liiis iorm of wrought iron rail was first introduced 

 nearly 12 years since on the St. Helen's Railway, by some contraclors, at his 

 suggestion, and the same rails were lately in use by the same persons, and 

 still good and serviceable, after continued use. Of late it had been recom- 

 mended by many engineers— among which Mr. Vignoles be ieved he was 

 among the first— to lay down the railway bars on bearings of timber, disposed 

 lengthways in the direction of the way, and upon which the iron had a j 

 continuous bearing, instead of having it supported at intervals (either wilh 

 or without chairs), as was the case when blocks or cross timber bearings vere 

 used. In describing the diflerent modes of laying rails, the Professor ob- 

 served that the heavy stone blocks being packed around, or boxed up with 

 ballast, kept the rails in place— that the cross s'eeper having both rails 

 attached thereto, the gauge or breadth was preserved ; with the longiiuilinal 

 system of bearings, the parallelism was retained by cross ties of wood, with 

 tenons, and sometimes by rods of iron with screw-ends and nuts, and occa- 

 sionally with both. It was necessary thus to provirle for preserving the 

 breadth of the railway, for, as the c.irriages and engines work along the 

 rails with a wriggling motion, there is always a tendency, by the lateraj 

 action of the fianges of the wheels, to push the road out of gauge. Mr. 

 Vignoles mentioned the two new lines added on the south side of the London 

 and Greenwich Railway as the latest examples of longitudinal timber bear- 

 ings ; but he observed that, as the great point in this system was to insure 

 that the rail be firmly attached to the wood, to prevent any vertical play, he 

 rcnsidered a more eflectual meihod might have been there used, so as to have 

 the iron continually united to the timber, on a plan which he had tried 

 with success, and to which he would presently advert. When iron was first 

 introduced for railways, it was for a long time merely a plating of metal on 

 the edge of the wood rail, on which plan, with iron bars of greater or less 

 ■Height, many of the lines in America had been laid.- Cast iron being ne.xt 

 introduced, the system of fastenings was necessarily changed, and the ori- 

 ginal longitudinal timbers abandoned for cross sleepers, or isolated stone 

 blocks. The rails being cast in lengths of three or four feet, it was found 

 expedient to prepare some contrivances to receive and fasten the ends to- 

 gether, and this was the saddle or chair. Some of these iron rails were cast 

 deeper in the middle, and, from their shape, got to be termed ■' fish-bellied,'' 

 this form being probably adopted with the idea of obtaining uniform strength ; 

 though, for railway purposes, the position of this increased depth was the 

 reverse of that given to bearers intended to resist quiescent weights. From 

 the action of the moving weight, however, upon rails »ith so many joints, 

 they soon got out of order. Wrought iron was then introduced, to get 

 greater lengths ; the first of these were rolled at a considerable expense of 

 useless ingenuity into the same form as the fish-bellied cast iron rails, the 

 length of 15 to 18 feet being divided into five or six flat ellipses. On most of 

 the lines where this description of rails was first laid, it has been found 

 necessary to take them up, and replace them, as they were found to break at 

 a short distance from the points of support. Mr, Vignoles stated that he 

 had, from the first, decidedly set his face against this form of rail, and 

 argued for and introduced rails with the same section throughout their 

 lengtli — since commonly styled /jariillcl rails, as distinguished from the " fish- 

 bellied rail," adding 10 lb. to the original weight of 35 lb. to the yard, by 

 putting on a lower rib or web, on the principle that gave such adilitiona] 

 stillness to all beams; this lo»erwebwas increased in size from time to 

 time, until, in a special report to the London and Birmingham Railway, Mr. 

 Vignoles recommended that the upper and lower webs, or buttons, should be 

 made precisely alike, to allow the rail to be turned up or down, or in cither 

 direction. This form was, h(;wevcr. first actually laid down by him on the 

 North Union Railway, and its advantages in the above respects haNe already 

 been appreciated and applied : these rails are about G5 lb. to the yard. The 

 Birmingham Company decided finally on adopting this form, increasing the 



• See Jeurnal. No. 1, Vol. I. 



weight to 75 lb. ; and. where chairs are used, it is now almost exclusively 

 employed, the weight being sometimes increased to 78 or 80 lb. per yard. 

 With the increase in the wei;;ht of the rail, the intervals between the sup- 

 ports also gradually increased from three to five feet, but with bad efl'ect. as 

 the expense of keeping a railway in order with the longer bearings (.as the 

 technical phrase is) was very much augmented ; and, on the London and 

 Birmingham Railway, intermediate supports had since been introduced, 

 wdiere the original bearings were five feet. Mr. Vignoles stated it as his 

 opinion, deduced from considerable experience .and observation, that where 

 chairs and supports, at intervals, were used, he considered a GO lb. rail, with 

 a .S-feet bearing, better than a heavier rail with a longer bearing. Blocks, 

 he observed, were, however, nearly ex [,loded as supports ; the cross sleepers 

 and chairs were still preferred by many engineers, but it was certain that 

 the closer the supports— that is, the shorter the bearings — the less the cost 

 of maintenance, and hence the inlerence, which experience everywdiere con- 

 firmed, that the continuous supports w ere best of all. In respect of fastening 

 the chair to the block or sleeper, and the rail to the chair, it was now almost 

 universally admitted and acted upon, that compressed wood was much 

 preferable to iron spikes, bolts, or keys. Mr. Vignoles introduced a number 

 of drawings, and described a variety of diagrams, illustrating the various 

 shaped rails and chairs, and modes of fastening adopted, and drew com- 

 parisons as to the advantagts ami cost of each. In reference to what he 

 had before stated of the disadvantageous method hitherto pursued in fastening 

 rails with flat bases to continuous timber bearings, by s|iikes or screws, the 

 Professor said that such a mode seldom continued to hold the rail close 

 down to the timber, and there ensued a certain quantity of vertical play of 

 the rail on the wood, often accompanied with a good deal of rattling, and in 

 the end, the head of the bolt or spike was absolutely jerked oS. Mr. Vignoles 

 said that the only efi'ective fastening was that used with Evans' patent rails, 

 which had a slit or groove of a dove-tail shape (in cross section) rolled for 

 the whole length of the rail in the bottom ; bolls, with similar-shaped heads 

 to fit, were passed into this groove, and dr.ipped at the necessary intervals, 

 through holes in the longitudinal timbers ; the bolt terminated in a screw, 

 and a washer and i:ut being put on, by means of a spanner, the nut drew 

 down the rail closely to the timber. Mr. Vignoles stated that he had bad a 

 considerable length of riilnay thus laid, which had been done some time, 

 and the rail had remained close dow n on the wood w ithout any play, or 

 getting at all loose. He concluded this lecture by stating that in the next 

 he would endeavour to draw a comparison between the modern heavy rail 

 and chair and fastenings, as used wilh cross timbers laid at intervals, and 

 the rail and fastening, as above described, to be laid on longitudinal timbers, 

 and having a continuous bearing thereon. 



I.ECTfRF. XI. 



In resuming the subject of the Upper Works of Railways, the Professor 

 said he would enter briefly into the consideration of the strongest form of 

 rail, afler explaining those points applicable alike to cast and wrought iron 

 bars. First, a certain breadth was required for the bearing surface of the 

 rail, for the wheel to run upon, and this breadth should be such as not to 

 be likely to produce improper action or grooving, in the tire or tread of 

 the wheel, and, at the same time, not to be increased so as to make the rail 

 needlessly heavy; there must also be a sufficient depth or thickness of that 

 bearing surface, to make it strong enough to withstand abrasion, and render 

 the rail sufliciently stitf, and capable fully of sustaining the action of the 

 driving-wheels of the locomotive engine. Hitherto the establi.shed breadth 

 seemed to have beeri about tw o and a half inches on the top web, or button, 

 and Mr. Vignoles thought, from experience, that that breadlli should be 

 considered the minimum ; however, the strength of this bearing part of the 

 rail, being as the breadth and square of the depth, a greater breadth than 

 absolutely necessary to prevent the tire of the wheels being grooved, woulil 

 add to tlie weight of the rail, without increasing the strength more than in 

 the direct ratio of the breadth, whilst the same quantity of material, disposed 

 in terms of the depth, increases the strength in the duplicate ratio. Con- 

 sidering the great increase of weight in the locomotive engine of late years, 

 and the continued wear and tear on the rail, from the action of the driving- 

 wheels, and looking to the state of the iron of the upper works of those 

 railways which have not very heavy bearing surfaces, it would seem that, 

 while two and a half inches is a minimum of breadth, the chief attention is 

 now required to the proper depth, to resist abrasion and exfoliation which 

 takes place, especially if tlie iron is not perfectly well rolled. Railway bars 

 are compounded of fagotted iron, and if the pieces are not properly welded 

 the bearing edge is broken down, and peels ofl ; but. supposing the iron 

 good, and the manufacture perfect, the heavy efl^ects of the engine must be 

 provided against, and experience shows that an inch and a half is not too 

 much for the depth of the top web, or bearing pari of the rail, and two and 

 a half inches being the breadth, then three and three-quarters— or. say four 

 ■square inches— should conslitute the sectional area of the part that is exposed 

 in receiving the direct action of the driving-wheels ; this is the section actually 

 requisite, and the greatest additional strength being to be obtained by in- 



