Railway Construction

by William Hemingway Mills

[Fig. 278] is a sketch of the modern rail as laid down on a rolled steel transverse sleeper, the rail being held in position either by turned-up clips, wedges, bolts, or any of the devices in use for similar duty in the rolled-steel sleepers for ordinary railway permanent way.

[Fig. 279] shows a modern rail of a heavier section, with a wide flange resting direct on a continuous bed of concrete. The gauge is maintained by bar-iron tie-bars placed vertically so as to fit in between the courses of the paving-setts, the ends being forged and screwed to pass through holes in the vertical web of rail, and secured in position by nuts. Both in this, and in type [Fig. 278], ordinary fish-plates are adopted at the rail-joints, as indicated by dotted lines.

In the last two examples above described all the materials are of the most durable description, and the least liable to wear or decay, but it will be necessary to guard against making the fastenings and the bars too light for the duty they have to perform. There should be ample material in the head of the rail to allow of a fair wearing down, and the continuous flange groove should be sufficiently deep to meet this wearing away without causing the wheel-flanges to strike the bottom of the groove.

Fish-plates.—In the first examples of the newly invented wrought-iron fish-plates they were made to the depth to fit in between the upper and lower tables of the rail, as shown in [Fig. 280], a small space or clearance being left between the inner sides and the vertical web of the rail. Ordinary nuts and bolts were used in most cases, but in some instances one of the fish-plates was tapped, as in [Fig. 281], forming one long continuous nut, and in others both fish-plates were tapped, as in [Fig. 282], and right and left handed bolts were used. Neither of the two arrangements of tapped fish-plates proved sufficiently successful as to lead to their general adoption. When the bolts became rusted in, or iron-bound, it was found to be almost impossible to remove them without permanently damaging the fish-plates. With the four right and left handed bolts the operation of tightening, or removing, the fish-plates was very tedious, as each

bolt had to be turned a very little at a time, one after the other. Independent bolts and nuts, either of iron or steel, are now universally used; plain holes, with sufficient allowance for work and expansion, being punched or drilled in the rails and fish-plates.

For many years the depth of the fish-plates continued to be made the same as the space between the upper and lower members of the rail, as shown in [Fig. 280]; but with the heavier loads and higher speeds of our modern railway working it has been found necessary to strengthen the joints by providing deeper or stiffer fish-plates, as shown in [Figs. 283, 284, and 285]. For bull-head rails the fish-plates have been brought down underneath the lower table, and in some cases extended down sufficiently far to admit of a second set of fish-bolts under the rail. For flange rails some fish-plates are used simply of the form of angle irons, and others have the angle portion carried out beyond the end of the flange, or foot of rail, and then turned down vertically to a depth of an inch or more below the rail. The latter makes a very strong fish-plate.

Fish-plates, like rails, are now almost universally made of steel.

The efficiency and durability of a fish-plate depends materially upon its angle of contact with the under side of the head of the rail, and the extent of its contact surface. It would be an error to suppose there is little or no wearing away in fish-plates, as in reality there is very considerable wear, and especially in rails of lighter section. If the under side of the head of rail has a curved outline, as in the rail in [Fig. 287], there will be some difficulty in ensuring a perfect fit in the fish-plates; the curve of the one may not quite correspond to the curve of the other, and the contact surface will be very small. It is better to make these contact surfaces in straight lines, and to a wide angle rather than to an acute angle. In [Fig. 288] the under side of head and corresponding top of fish-plates are set at an acute angle, and fish-plates to this pattern will soon wear up to the vertical web of rail, and cause a loose noisy joint.