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inches, and four feet, but other intermediate guages have also been used.

Advocates of the broad guages believe that the greater stability of the track and the consequent reduction in haulage expenses, the increased capacity of the broad guage mine cars, the reduction in the outlay for rolling stock, and for repairs to the same, more than equal the disadvantages of broad as compared to the narrow guages.

Advocates of the narrow guages think that the ease of hauling around sharp curves, the reduction in cost of construction, and the use of mine cars with inside wheels, are advantages greater than those advanced by the broad guage adherents.

The maximum size of mine car that can be economically used is limited in its dimensions, (length, breadth, and height,) thus, -the length is limited to about ten feet, because any increase beyond this necessitates a broader wheel base to insure stability, the height is limited by the height of gangway and several other requirements, and the breadth is limited by the width of the gangway and turnouts.

It is certainly advantageous in some cases to decrease the height or length of a car and increase its width, and the broad-guage advocates have always advanced this as one of their cogent arguments in favor of the broader guages. But since the width of the car may be increased and the guage narrowed by building the cars with inside wheels (wheels inside the bed-frame) and as cars so built run more smoothly than the outside wheel cars of the broad guages, the whole controversy eventually concerns the relative merits of inside and outside wheels. This will be considered in detail in the chapter on rolling stock.

My own preference is for the narrow guages and cars built with inside wheels. Cars holding from ninety to one hundred and twenty cubic feet are built with inside wheels to run on guages of from two feet nine inches to three feet and three inches, and the results seem to be more satisfactory than when the guage is increased to four feet and the wheels placed outside.

Nearly all of the Philadelphia and Reading Coal and Iron

Company's methods of working shown by the plates reproduced from Report A' represent the guage as four feet and the cars are shown as outside wheelers, but this was simply a guage adopted for the illustrations, and is not to be taken as a type of all their operations.

In the Wyoming district the narrow guages have a firmer footing, and inside wheelers are more common.

Sills.

The sleepers used on inside haulage roads vary from the size of a regular surface railway sill down to sticks not much larger than a man's arm.

They are generally from four to six inches thick and from five to eight or nine inches wide-in other words they are usually made of round stuff six to nine inches in diameter hewed flat to a thickness of four to six inches.

At some collieries round stuff is used with two notches cut at the proper places to seat the rail, or the sill may only be hewed flat on one side, but these plans are seldom adopted at large collieries.

Their length is from four to six feet, depending on the guage of the road.

Switches.

The switch or "latch" most commonly used is shown by Fig. 31, in which a movable bar "b" is shown replacing the frog commonly used.

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Fig.31.

When the branch or siding is in constant use an ordinary

railway frog is substituted for the bar "b." The latches a, a, are wedge-shaped bars of iron (made as high as the rail) with an eye in the thick end.

They are sometimes connected together by a rod attached to a lever so that they may both be moved at once from the side of the track or by a person situated at some distance.

This switch is made self-closing or automatic whenever it is necessary to run all the cars off at the branch, or to let all of them pass the branch (the switch then being used only to admit cars to the main track) by attaching the latches through a bar or lever to a metallic spring, a stick of some elastic wood, or a counter weight, to pull them back into a certain position whenever they have been pushed to one side or the other by the passage of a car on the main track. Figs. 35, 36, 38, and 39 show some of the applications of these spring latches or automatic switches.

By a similar arrangement, in which two counterpoise weights are used, the car may be made to set the latches, and sometimes the car is depended upon to effect this without the assistance of counterweights. (See Figs. 37 and 39.)

The counterweights used for this purpose are usually set on a rocking arm or lever oscillating a short distance beyond the vertical on one side, and through a greater arc on the opposite side of the center. The car opens the switch a certain distance moving the weight over the center; the weight then falls, carrying the switch over, and setting the latch firmly against the rail.

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A modification of this switch is shown by Fig. 32, which

represents a form of double switch largely used at the Lehigh Coal and Navigation company's collieries. These latches are set by the drivers, who kick them over and drop a small square of plate-iron between them to hold them in place.

This switch costs more than the other style, and is better adapted to outside roads than to the mine roads inside.

The ordinary movable rail switch in common use on all surface railways is also used to some extent in anthracite mining. It is commonly used on slopes arranged as shown by Fig. 37, to replace the "latches set by the car," and is also largely used on the mine roads at the surface.

Ordinary railway frogs and grade crossings are used throughout the region, but the grade crossing is sometimes replaced by a small turntable, which then answers two purposes, and sometimes by the arrangement shown by Fig. 33, in which four movable bars are thrown across the main track whenever the other road is to be used.

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The subordinate road is built about one and a half to two inches higher than the main road to allow the bars to clear the main track rails.

Rails.

Wooden rails are not used on main haulage roads. In

buggy breasts driven up rather steep pitches wooden rails are sometimes used, but even in such cases the track is often of iron and wood combined.

On steep gangway roads a wooden tram is sometimes laid against the rail to increase the friction and enable the runner to control the descent of the car.

Strap-iron rails have been almost entirely replaced by the forms shown by Fig. 34. In this, as in many other respects, mine railroading has availed itself of the improvements effected in surface railroading, and the heavier rails now used are identical in form with rails now laid on some of the narrow-gauge steam railways.

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The joints and fish-plates are often the same with those used by narrow-gauge roads, but on many mine roads, especially those not used as main haulage roads, no fish-plates are used, the end of the rail being held in place by two or three spikes driven into a sill lying beneath the joint, or the joint is made by a shoe or chair which receives the ends of both rails.

Turnouts.

On gangways used as main haulage roads it is usual to place turn-outs at certain intervals to allow the loaded and empty "trips" (trains) to pass. These turnouts are commonly constructed by widening out the gangway to the required width for two tracks, and for a sufficient distance to accommodate from five or six up to fifteen or twenty cars. The switches at each end may be made self-acting so that the empty trip coming in is thrown on the turnout, and in running out on the main track at the other end the cars open the switch, which immediately closes.

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