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THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[July, 



" On a nm-funn of RaHnay Chairs and imjiroved Fai/enini/s." By Charles 

 May, Assoc. Inst. C.E. 



At tlie suggestion of Mr. Cubitt, V.P., a series of experiments was insti- 

 tuted at the works of Messrs. J. R. & A. Ransome, of Ipswich, for the pur- 

 pose of determining the most advantageous form of tlie chairs, and most 

 secure mode of fastening them upon tlie sleepers of the South Eastern Rail- 

 way. The result of these experiments has been to produce the cast iron 

 chairs, and wooden treenails as fastenings, which were exhibited at the meet- 

 ing, and described by the author. 



In the event of a chair breaking, it is desirable that the fracture should 

 occur in such a manner as to |)revent any of the loose pieces being thrown 

 into situations where they would interfere with the passing trains ; to ensure 

 this, the weakest part of these chairs is across the seat — they are, however, 

 stronger in that part than any other chair now in use. In order to ascertain 

 the proper relative proportion between the strength of the jaw and that of 

 the seat, many experiments were made by varying the forms, and wedging 

 the chairs, until they broke, sometimes in one and at other times in the other 

 part ; it was then easy to add so much strength to the jaw as would, without 

 waste of metal, cause the fracture to take place invariably across the seat. 



For the purpose of ensuring perfect accuracy of form, with a smooth inter- 

 nal surface, so that wedges of a uniform shape and size might be used, the 

 chairs arc cast upon metal cores ; the joint-chair has an upper piece, over- 

 lapping the wedge, to keep the rail in a perpendicular position, and to pre- 

 vent the end of it from being thrown up or forced away laterally, if the wedge 

 should accidentally be removed. This form of chair was originally planned 

 by Mr. John Harris, the engineer of the Stockton and Darlington railway, 

 where it has been in use above twelve months, giving perfect satisfaction. 

 The rail is so placed in the intermediate chairs, that when it receives the 

 pressure of the wedge, it is held firmly down on the seat, against the lower 

 part of the jaw, and at the upper part against a slightly projecting rib, which 

 bears against the neck of the rail. 



The holes for the fastenings are so arranged as not to be in the same line ; 

 a large portion of the current expense of the maintenance of way on railroads 

 arising from replacing the sleepers which have been split by the spikes being 

 driven in the same line in the grain of the wood. 



The mode of fastening adopted in this case is, to use treenails of dry Eng- 

 lish oak, compressed into two-thirds of 1 heir original bulk, by being forced 

 under a fly press, into metal tubes, in which they are placed in a chamber 

 heated to about 180'', where they remain 16 hours : the pressure upon the 

 body of the treenail (the head not being compressed) is sufficient to mate- 

 rially increase the specific gravity without injuring the fibre, or diminishing 

 the strength of the wood, and it retains the form thus given until it has been 

 driven into a damp sleeper, when the expansion is sufficient to fix it firmly. 



The ordinary mode of fastening chairs with iron spikes has been found dis- 

 advantageous, because one blow too many causes a reaction, and frequently 

 loosens them, whilst treenails may be driven to any depth, and the heads 

 subsequently split with smaU wedges if necessary. 



Rails should be ' keyed-up' so tightly as to ensure security, still leaving a 

 large rimnunt of stirplus strength in the chair to resist any shock to which 

 they may be exposed : — with wedges of varying dimensions, the chairs, wliich 

 are frequently of unequal quality, and carelessly cast, are liable to be brought 

 nearly to tlie breaking point, and to give way as soon as they arf subjected to 

 any additional strain. This has been avoided in the chairs and wedges under 

 consideration, by giving them exact uniformity of dimensions. 



The wedges adopted are of English oak, cut out of square timber, so formed 

 as to drive equally well with cither side to the rail, and compressed into five- 

 SLXths of their bulk, by the same process as is used for the treenails. 



Many advantages will result from this form of cliair and wedge, with the 

 treenails for fastening; the time occupied in laying the rails is diminished ; 

 the holes for the fastenings may be bored in the sleepers by machinery, at a 

 diminished cost, and greater accuracy of gauge obtaiued at the same time; 

 the required inclination of the rail being given in the chair, no cutting away 

 of the sleeper is necessary ; the sole of the chair is fixed horizontally upon 

 the surface of the sleeper, and all of them may be placed accurately in the 

 same plane, thus bringing to hear upon the hitherto roughly executed details 

 of railway engineering, those mechanical contrivances by wliich the cost is 

 diminished, whilst the dependance upon the skill and attention of the work- 

 men is avoided ; at the same time insuring the accuracy of the line, upon 

 which so large a portion of the economy of working a railway depends. 



Specimens of the chairs, wedges, and treenails, accompanied this commimi- 

 tion. 



Mr. Cubitt observed, that two modes of preparing treenails had been 

 hitherto adopted : one was, by forcing the wood through a steel die, in which 

 case neither the form nor the diminished bulk was preserved, as on leaving 

 the die it swelled nearly to its original size. The other was by passing the 

 wood between rollers : this latter process had been found to cause permaueut 

 injuiy to the fibre of the wood, by crushing the capillary tubes, and conse- 

 quently depriving it of much of its strength. To the mode of preparing the 

 treenails under consideration, neither of these objections existed. He antici- 

 pated many advantages from the use of this form of chair, wedge, and fas- 

 tening. They would certainly be cheaper even in the first cost than the 

 ordinary chairs, fastened down by iron spikes. The usual calcul.ition for a 

 double liriC of rail was 880/. per mile for the chairs, wedges, and spikes. The 

 cost of these chairs, with the compressed wedges and treenails, would be 

 786/. per mile. The price of the compressed treenails for railway purposes 



would be J/. 10*. per thousand ; that of iron spikes was 6/. J*. per iliousand. 

 The wedges 2^ inches square, cost 21. per tliousand for each inch of their 

 length, so that those for the joint-chairs, which are 8 inches long, average 

 16/., and those for the intermediate chairs, of 6 inches long, cost about 12/. 

 per thousand. Each joint-chair, with wedge and treenails, costs 2s. lOrf. ; 

 and the intermediate ones, with their appendages, 2s. Id. eacli. 



One great cause of expense on railways was the fracture of the chairs dur- 

 ing the laying. lie knew an instance where in a length of 20 miles of rail- 

 way 180 tons of chairs had been broken, either by wedging or in driving 

 down the spikes. This was in the ratio of one chaur in ten. In the ordinary 

 mode the oak wedges are driven home by a 14 tb. sledge hammer, whereas 

 with the new cliair the compressed wedges and trenails are driven by a light 

 wooden mallet. 



Mr. Pim remarked that the wood fastenings used for the chairs on the 

 Dublin and Kingston Railway had been compressed by rolling. He con- 

 sidered the present plan much superior. 



Mr. Viguoles corroborated the statement of the cost of chairs of the ordi^ 

 nary construction. On the railways of the north of England oak treenails 

 had been used as fastenings for a considerable period. The plan now pro- 

 posed presented many advantages, not only in the construction of the chairs, 

 which appeared well designed and excellently cast, but in the form and mode 

 of preparation of both the wedges and the treenails. 



In answer to a question from the President, whether the compressed tree- 

 nails could be applied with advantage in sliip building^Mr. Mills was of 

 opinion they could be so employed, provided the fibre was not injured by the 

 process. He believed that sound wooden treenails were better fastenings for 

 ships than iron bolts, and quite as good as copper, whilst by their use the 

 expense was materially reduced. Turned treenails of locust wood were at 

 present preferred to all other kinds. 



Mr. S. Seaward understood that, at the Royal Dockyards, treenails which 

 were crooked as much as three times their own diameter were preferred to 

 straight ones. He believed that the late Mr. H. Maudslay had constructed 

 some machinery expressly for turning them crooked. 



Mr. Hawkins remarked that the treenails were frequently crooked, because 

 the rending caused them to follow the direction of the grain of the timber. 

 Twenty-two years since, Mr. Annesley took out a patent for budding ships 

 without ribs. He used for fastenings, treenails compressed by being forced 

 through steel dies, just before driving them into the jilanks, so that their ex- 

 pansion fixed them firmly in the planking. He buUt a vessel of very light 

 construction, the sides of which were formed of five thicknesses of J-inch 

 boards, held together by compressed treenails, without any ribs. It had 

 proved very stiff and durable. 



In reply to a question from Mr. Yignoles, whether the swelUng of the 

 compressed treenails in the ribs would not have the effect of preventing the 

 possibihty of the "butt end" of a plank starting — Mr. Mills believed that 

 such an event was of rare occurrence ; treenails were subjected more to a 

 lateral strain ; they were frequently " backed out" after the planks had been 

 fitted into their places ; when the latter were properly bent they retained their 

 shape, and had no tendency to spring out. 



Mr. S. Seaward, in support of the opinion that leaks did occur from planks 

 starting, instanced the " Marquis of Huntly," East Indiaman, which was in- 

 jured in the JJowns, by a collision with another vessel ; she proceeded on her 

 way to China, but during the whole voyage out and home forty extra men 

 were employed at the pumps. On being taken into dock, it was found that 

 the " butt end " of one of the bow planks had started for 9 or 9 feet in length, 

 and nothing but constant labour and attention had kept the ship afloat, at an 

 expense of 7,000/. to the owners. 



March 9. — The President in the Chair. 



The following were balloted for and duly elected : Joel SpUler, as a Mem- 

 ber ; John Pope, as a Graduate ; Thomas Routledge and Frederick Taylor, 

 as Associates. 



" Description of a Bridge for a Haibcay crossing alove a Turnpike Road, 

 where the depth between the soffit of the Bridge and the surface of the Rails 

 is limited, to twenty-one inches." By John Pope, Grad. Inst. C.E. 



This bridge was designed by Mr. W. Cubitt, V.P., to meet the conditions 

 of a clause in a Railway Bill, which required that there should be a clear 

 width of opening for headway through the bridge in every part, 30 feet wide 

 by 20 feet high, whilst at the same time the height of the embankment limited 

 the space between the under side of the bridge and the surface of the rails to 

 21 inches. 



The railway is carried on three cast iron girders, each 3 feet deep at the 

 centre, diminishing to 6 inches at each end, with a bearing of 2 feet on cast 

 iron wall-plates, supported by brickwork abutments. The flanches of the 

 girders are 8 inches wide, and the metal every where 2 inches thick. Balks 

 of Memel timber, 12 inches square, are laid transversely, close jointed, their 

 ends bearing upon the flanches of the girders : on these timbers the chairs are 

 fixed, and the rails are laid. The whole depth employed is — 



The flanch of the gurder - - 2 inches 



Thickness of timber balks - - 12 „ 



Depth of the rail and chair - 6^ „ 



20J 



