It should not be forgotten that the cost of fuel per ton at the mine, or even the cost when delivered at the coaling-stations, is by no means the measure of the economy in fuel. The value of fuel per ton depends on its heating capacity, and varies from the value of wood (which is still used in some places where it is exceptionally cheap) as fuel, up through various grades of coal to the use of oil, which furnishes more heat per ton than any other grade of fuel. For general use we may ignore these two extremes, since in nearly all localities wood for fuel is not only costly, but of comparatively little value. At the other extreme, oil for fuel is almost impracticable, except where the Texas oils, whose composition gives them a particularly high fuel value, are sufficiently convenient to make their use economical. One ton of fuel-oil has a heat equal to about 1« tons of good coal or two tons of lignite. The saving in hauling of fuel, the ability to regulate the firing so as to produce a uniform heat, the actual saving in repairs to the fire-box, the utter absence of expenses incident to ash-handling plants, combine to give this method an economy which is even greater than would have been indicated by the comparative cost in cents of evaporating 100 pounds of water.
The amount of fuel burned per train-mile varies from a little more than zero (when the train is floating down a grade with steam shut off) to the maximum when working at full capacity. The amount of fuel burned will usually average 120 pounds per square foot of grate area per hour, but it may be forced up to 200 pounds and more, although at a great loss in efficiency. The grate area is usually from 20 to 35 square feet, except for fire-boxes of the Wootten type, which may reach nearly 90 square feet. The maximum fuel which may be handled by one fireman, for steady work, is about 4000 pounds per hour. As an average figure, a freight-train will use 225 pounds of coal per mile and a passenger-train 125 pounds.
It sometimes happens that it will pay to haul coal from a more distant source, considering the price which is paid for it, rather than use a coal which is mined much nearer, because the actual amount of ton-miles of energy produced may be greater with the more expensive coal. For example, the values of different fuels have been carefully determined and classified according to the number of ton-miles which can be obtained per pound of coal. A few of these values, which, however, must be considered as average values, are as follows: 7.00 for Pennsylvania anthracite, West Virginia New River semi-bituminous, and cannel coal; 4.35 for Iowa lignite; and 4.25 for Colorado lignite slack.. After all, the real question is to determine how to get the most heat for an expenditure of $1.00 at the coaling-stations. Since the cost of hauling must be included, any set of values made out for one locality are almost worthless for any other locality. As an example, a few values are extracted from some computations made by W. H. Bryan as to the real value of three grades, of coal in St. Louis.
It may be observed from the following tabular form that for a coaling-station located at St. Louis the common slack obtainable in that locality is by far the cheapest coal to use, regardless of its cost per ton. There is one slight compensation which reduces the apparent disadvantage of these figures. The anthracite coal will produce 40% more heat per pound than the common slack, and therefore the expense of hauling the extra weight of slack in order to produce a given amount of energy from the coal, as well as the necessity for re-coaling more frequently with the cheaper grade of coal, gives the anthracite coal an advantage which would make it the more economical coal if the values given in the last column were equal or nearly so. Of course in the above case those advantages are utterly swallowed up by the cheapness of the common slack.
Kind of coal.
Cost per ton.
B. T. U. in one pound.
Cost of evaporating 100 lbs. of water.
Pocahontas bituminous ..........................
Common slack ....................
In computing the real cost to a railroad of the fuel which it uses, the cost of the coal to the point where it is delivered to the road from another railroad is but an item of the total. There must be added to this the real cost to the road of hauling it from the point of delivery to the various coaling-stations. The actual cost of this will of course vary with the different roads, but it will seldom be less than 1/2 c. per ton-mile, which is the same as adding 50 c. per ton to the cost of the coal for each hundred miles it is hauled from the point of delivery.
Handling the coal at the coaling-station adds another item to its real cost to the road. The old-fashioned method of shoveling from a coal-car to a platform or bin, and from there again shoveling into a tender, will add at least 25 c. per ton to the cost of coal. The various devices for handling coal cheaply, although they reduce the cost of handling the coal, add an interest charge to pay for a more or less expensive coal-handling plant. The cost of handling coal by means of the modern coaling-station will usually average 3 c. per ton, and it is easily demonstrable that such a method is economical even to the point of paying the interest and maintenance on the cost of the plant, provided the business of the road is sufficiently large to justify such a plant.