1819.1 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



183 



These observations would seem to confirm the conjecture pre- 

 viously hazarded, that under the weights now given to the engines, 

 and with the limited extent of the tyre in contact with the rail in 

 section, the rails themselves are gradually crushing; and remem- 

 bering that the theoretical line of contact of the tyre on the rail 

 in section must in all cases become a surface of greater or less ex- 

 tent, this effect is more to be attributed to engines with small 

 sized wheels used for goods traffic, than to the weight or speed of 

 engines for express traffic, whose wheels are so much larger in 

 diameter. And could the matter be investigated, it would be 

 found that the rails suffered more from the passage of goods or 

 mineral trains, than from that of passenger trains at whatever 

 speed. 



Fig. 1. — Longitudinal Elevation 



slightly larger than those in the cross sleepers to prevent the tim- 

 bers from splitting. The rails may of course be manufactured in 

 such lengths as may be most convenient, and the cross sleepers 

 distributed accordingly, and it may be found that the sleepers 

 maybe placed at wider intervals. The longitudinal timber is to 

 be secured at the ends by a common half-lap joint, this joint to be 

 always on one of the middle sleepers, and not under the joint of 

 the rail. 



A modification of this road is shown in figs. 3 and 4, in which a 

 longitudinal timber V2 by i in. is used, and the chairs not let into 

 the timber, but a saddle, .?, introduced between the chairs. The rails 

 may be secured to the chairs either by a hard wood or wrought-iron 

 key; the latter of which is more efficient, as it is not affected by 

 with Chairs let into Timbers. 



u 



a 



» 



Tig. 3.— Longitudinal Elevation, with Intermediate Saddles. 



Fig. 2. Fig. 4. 



On the preservation of the perishable parts it would be beyond 

 our limits to enter. Payne's process certainly has some effect in 

 rendering the timber uninflammable, and therefore possesses ad- 

 vantage in the case of timber viaducts, or the planking of bridges. 

 Saturating the timber with creosote, as adopted by Mr. Bethell, 

 has produced very satisfactory results in preserving the timber 

 from dry rot or decay. 



The length to which this paper has extended will prevent more 

 than a very cursory description of a permanent way which would 

 embody the more desirable feature of efficiency and stability. 



The engravings, figs. 1 and 2, show a wide double T-rail repre- 

 senting a fair bearing surface to the tyre of from 2 inches to 2i 

 inches, and possessing a considerable amount of side stiffness, being 

 in depth 4 inches, and in width 3^ inches, and weighing about 

 100 lb. per yard. 



The rail is secured by chairs to a longitudinal timber, 1 1 inches 

 and 5i inches, the chairs being sunk into the timber till the bottom 

 surface of the rail is in contact with the top of the timber, along 

 which a slight groove is cut, of such a shape that the rail shall 

 bear harder on the outside edges of the groove than in the centre. 

 Beneath the longitudinal timber, are sleepers of triangular section 

 placed immediately under the chairs, 2 ft. 6 in. apart at the joints, 

 and l feet in the centre of the lengths of rail, these last being 

 supposed in lengths of 17 feet. The sleepers are cut out of 

 10 inch balk, and retain the road in gauge, whilst presenting an 

 additional amount of bearing surface on the ballast, and admit of 

 being packed without much removal of the ballast. In fact, these 

 sleepers offer peculiar advantages for this mode of construction, 

 although any others might be used. The chairs are secured 

 through the longitudinal timbers to the cross sleepers by hard- 

 wood tree-nails, the holes in the longitudinal timbers being bored 



wet or dry, and it prevents the rails from driving forward in the 

 chairs. The wrought-iron keys are more costly, but as in this 

 case they are merely composed of short lengths of iron tube, the 

 difference in expense would not be considerable. There is a 

 difficulty in replacing the chairs which will readily be seen by the 

 members, but in practice this may not be found a very serious ob- 

 jection. 



The President observed, that it was an important subject for considera- 

 tion ; the main question seemed to be, whether the surface of the rails was 

 actually suffering from the crushing action that Mr. Hoby spoke of. It 

 looked almost as if they had reached the limit of their powers, when they 

 began to crush the material. 



Mr. M'CoNNELL thought that a greater breadth of bearing surface of the 

 rails would not be found to yield the advantage anticipated by Mr. Hoby ; 

 as it was so difficult to keep the bearing of the wheels in a straight fine, and 

 extending over the whole surface of the rails. 



Mr. WooDHOusE remarked, that the rail proposed appeared to him rather 

 shallow for the purpose, being only 4 inches deep. 



Mr. M'CoNNELL said, he should be afraid that the rail would deflect be- 

 tween the saddles when a heavy weight passed over. 



The President observed, that the rail was very considerably increased 

 in thickness laterally, and appeared a strong rail, but it must be remembered 

 that the strength was diminished in proportion to the square of the depth. 

 He did not attach so mwh importance as the writer of the paper appeared 

 to do, to the fact of the permanent way fiaving deteriorated more rapidly in 

 the last three or four years than previously. It was certain that on the 

 older railways, which had been at work for 13 or 14 years, the deterioration 

 of the rails had been much more rapid during the last three years of the 

 time than the first three years, but he thought the wear and tear of the 

 present rails had been much overrated. It must be remembered that the 

 present heavy engines had been increasing in weight, whilst the rails had 

 been getting older and more worn ; aud he believed that the weight of 

 the present engines had got pretty nearly, if not quite, to the feasible limit. 



Mr. WooDHOusE remarked, there was an objection to the proposed plan, 

 that broken chairs could not be replaced without taking the rail out, which 

 would be very objectionable. 



The President observed, it would certainly be a serious objection if the 

 rail bad to be taken out in order to replace a broken chair: all practical men 

 were averse to it. He thought the lip on the inner side of the saddles 

 might be dispensed with, which would allow them to be changed without 

 disturbing the rail. 



[The paper "On a Patent Solid Wrought-iron Wheel," by Mr. Hbnry 

 Smith, owing to its length, we are obliged to postpone until next month, 

 but we give the two shorter papers which followed it.] 



