178 



NORRIS'S RAILWAY JOINT CHAIR. 



[1854. 



one in its place. This is done by heaping dry sand around the 

 chair, as it stands in its place, and then running metal into the 

 cavity so formed, leaving a lip projecting over the chair. Only 

 a few of these have yet been put down; but they have stood 

 the test of two years' working over without failure, and are still 

 tight. In casting, the hot metal running into the chair expands 

 it, and its contracting upon the cast key in cooling makes it 

 tight. 



It may be remarked, that the new chair occupies exactly the 

 same position on the sleepers, and has the same fixing, as the 

 common joint-chair; so that in case of damage to the line from 

 accident or slips, it can be repaired quickly in the ordinary man- 

 ner, by using the old chairs and wood keys until the same 

 cupola can be brought to bear. 



Mr. Morris exhibited specimens of the chairs and the cast iron 

 mould, complete; also a specimen of one of the new joint-chairs 

 from the North Union Railway, which had been laid down for 

 eighteen months in a line of great traffic, where 500,000 wheels 

 had passed over it during the time; the two rail ends were cut 

 off, and remained fixed fast in the chair, and the surface of the 

 joint was level and smooth, although the rail ends had been 

 much indented at the time the chair was cast on, from the rails 

 having been recently turned. 



The Chairman inquired what length of line had been tried 

 with the new chairs and how long they had been at work? 



Mr. Norris replied, that five miles had been recently laid with 

 these chairs near Rugby, and about a mile was previously laid 

 near Crewe, and elsewhere, which had mostly been at work one 

 and a half years. 



Mr. Woodhouse said, the recent trial of the chairs near Rugby 

 had been made under his superintendence, and he had found 

 the result highly satisfactory. It had been intended to relay 

 that portion of the line during the present summer ; but the new 

 joint-chairs had proved of such benefit, that they would probably 

 give several years additional life to that road. He consequently 

 recommended the adoption of the plan on a considerable length 

 at other parts of the line, which was now in progress. 



The Chairman asked what difference was felt in the train 

 ruuning over the joints on the portion that had been altered at 

 Rugby ? 



Mr. Woodhouse said, the joints could not be felt at all with 

 the new chairs; there was no comparison of the ease in travel- 

 ing over the old plan of joints. 



The Chairman asked what was the usual time required for 

 the process of casting the chairs ? 



Mr. Woodhouse replied, that the average of the work done at 

 Rugby was about one chair cast every four minutes, including 

 the whole process of preparation. 



Mr. Slate remarked, it was certainly a very ingenious process 

 of casting the chairs, and must make a thoroughly firm joint; 

 he inquired what was the expense of casting? 



Mr.Norris said that the labor of casting cost about 6d.per chair, 

 and the cost was about Is. per chair, including all expenses ex- 

 cept the metal, which weighed about 50 lbs. The expense of 

 casting was much diminished as the men got more experienced 

 in managing it. At first they could only cast 40 chairs per day, 

 but the rapidity of casting increased with practice to 80 per day; 

 and now 120 per day were cast by common plate-layers, who 

 had never before had anything to do with melted iron. 



Mr. Slate said he had seen the first of these chairs one and a 



half years since, and had then an unfavorable opinion of their 

 standing in work from the great contraction of the melted metal 

 in cooling on the rigid rail: but it appeared that the wrought 

 iron rail was expanded by the heat of the melted metal sufficient- 

 ly to make the chair safe by its contraction again in cooling. He 

 thought the new chair made a very perfect coupling of the rail 

 ends, and was a great improvement on fishings and other plans, 

 which he could only regard as makeshifts ; and though they had a 

 very good effect compared with the previous plan of having 

 nothing to couple the rails together at the joints, they were still far 

 removed from perfection. The new chair might be said to be 

 quite perfect, if it could be made quite fast on the rail without 

 allowing it to slide. 



Mr. Norris observed, that only every third or fourth joint waa 

 made a slip joint for expansion ; he was aware what a great 

 advantage it would be to have no slip-joints, and by no means 

 maintained that to be impracticable ; the expansion of the rails 

 successively by the heat of casting the chairs on, would perhaps 

 elongate them sufficiently to make provision for the expansion 

 from the highest temperature they would be afterwards exposed 

 to, and the tension would then resist the contraction from cold. 



Mr. May remarked, that Mr. Brunei had now many miles' 

 length of Barlow's rail on the South Wales Railway, all rivetted 

 fast - together, without any provision for expansion and no 

 difficulty was experienced in consequence. There was some 

 misconception on this point, respecting the action of ex- 

 pansion ; it was limited in amount of force, and if opposed by 

 a greater force, no amount of expansion or contraction could 

 take place. Wrought iron raised in temperature 15° was expan- 

 ded 1-1 0,000th of its length, and exerted a force of 1 ton 

 per square inch of section by the expansion ; consequently, no 

 expansion of the rails would take place if a resistance 

 were opposed of 1 ton per square inch for each 15° rise 

 of temperature. He thought it probable that Mr. Norris's plan 

 ultimately would require to have no expansion joints to perfect 

 it, and in many cases he did not doubt the plan being an ex- 

 cellent one. 



Mr. James Nasmyth said he had witnessed the whole process 

 of casting the chairs, and fitting on the iron moulds, and con- 

 sidered it a very successful plan, and of the utmost value and 

 importance to the durability of the line as well as to the safety of 

 the public. The trains ran foil speed over the red hot chairs 

 directly after they were cast. He thought the slight tortuosities 

 of all roads, even in the straight parts, would be probably found 

 sufficient to allow for the effect of expansion, without making 

 any provision of slip joints. 



Mr. May suggested, that an experiment could readily be tried 

 to ascertain the actual amount of expansion of the rails, by 

 having a number of thin graduated wedges, to be dropped into 

 the joints at the hottest part of the day and at night, to measure 

 the amount of expansion over a considerable length of rail. It 

 would probably be found to be very insignificant, as the ordinary 

 chairs offer a considerable resistance |to a longitudinal motion of 

 the rail, by the hold of the keys on the rail, the chairs on 

 the keys, and the ground on the sleepers; though of course the 

 resistance in Barlow's rail was a different case, where the rail, 

 chair, and sleeper were all one. 



Mr. Woodhouse remarked, that in laying the rails the men 

 place small wooden or iron packing pieces, 1-1 Cth of an inch 

 thick, between the rail ends at the joints, to make the ordinary 

 allowance for expansion ; and they always find that if these 

 pieces are put in early in the day, they become so tight in the 



