Growth of mileage and traffic in the United States since 1889, [77].—Increase of earnings, [79].—Operating expenses, gross and net income, [80].—Comparison with earlier decades, [85].—Density of traffic, [86].—Increase of train loads, [88].—Limitations upon their economy, [92].—Heavier rails, [93].—Larger locomotives, [94].—Bigger cars, [95].—Net result of improvements upon efficiency and earning power, [97].
The law of increasing returns due to financial rather than operating factors, [99].
A railroad theoretically presents a clear example of an industry subject to the law of increasing returns—that is to say, an industry in which the cost of operation grows less rapidly than the volume of business done. Each ton of freight added to the existing traffic costs relatively less to haul. From this it follows, obviously, that the net returns increase more than proportionately with the expansion of traffic. This may be demonstrated by a simple calculation. It has already been shown that only about two-thirds of the total expenditures of a railroad are applied to operation, the remaining third being devoted to capital account. Moreover, of these two-thirds of the total applied to operating outlay, only about one-half responds to any change in the tonnage, the other half being constant up to a certain point. Otherwise expressed, an increase of one per cent, in traffic and, therefore, of revenue, produces an increase in expense of only one-half of two-thirds of one per cent.[50] Two-thirds of the entire increment of revenue goes to profit. Carry this increase further and the effect is more striking. Suppose traffic to grow tenfold. The former outlay being $100 for a given volume of business, would be divided according to our rule as follows: one-third for fixed charges, one-third for constant operating outlay and one-third for variable expenses. With ten times as much traffic, only the last group of outgoes will expand. One thousand dollars revenue would therefore become available under the new conditions, to pay the same fixed charges as well as constant operating costs. The total outgo would thus become $33 plus $33 plus $330, or $396 in all. Almost two-thirds of the increment of revenue still remains as profit. It might well happen that such an expansion could not ensue without large increases in the capital and plant, as has already been noted; but up to that point this calculation would hold good. The following statement varying but slightly from our foregoing assumptions, illustrates the principle.[51] Let the distribution of expenditures for given conditions, producing $100 of revenue, be these, viz.:
| Operating expenses | $ 67 |
| Fixed charges | $ 28 |
| $ 95 | |
| Profits for dividends | $ 5 |
| $100 |
Now assume an increase of ten per cent. in the traffic and consequently in the revenue; but assume also that the average extra cost per unit, of the new business, is only forty per cent. as much as for the preëxisting tonnage. Were the added cost of each ton mile as great as before, the operating expenses would rise by the full ten per cent. of $67. But on Webb's assumption, they will rise by only forty per cent. of ten per cent. The new account would then stand thus:
| Operating expenses ($67 plus forty per cent. of ten per cent. of $67) | $ 69.68 |
| Fixed charges as before | $ 28.00 |
| $ 97.68 | |
| Income, increased by ten per cent. | $110.00 |
| Balance for profit or dividends | $ 12.32 |
By an increase of ten per cent. in tonnage, balance for dividends has more than doubled.
In this connection it will be noted that a constant rate of return per unit of business newly acquired has been assumed. Attempts were made on behalf of the railroads, during the long period of decline of ton mile revenue down to 1900, by Newcomb and others, to show that this is an unreasonable assumption; in that increased traffic is presumably to be had only by a progressive lowering of the rates charged. This contention has been effectively demolished by the steady and remarkable growth of traffic since 1900, even in the face of a substantial rise of rates all along the line. A necessary corollary to our proposition, beside that of the maintenance of a constant scale of charges, is, of course, also of the continuance of a given grade of service and of costs of operation. If more luxuriously appointed passenger trains or quicker freight service have to be given in order to produce the growth of business, the added costs of operation must, naturally, be taken into consideration. If widespread rise of wages follows an increase in the general cost of living, that too is an entirely extraneous factor. But with a given grade of service, constant rates and steady wage scales, there can be no question, up to the point of full utilization of the existing plant, that the operation of railroads affords clear demonstration of the law of increasing returns.
The obverse side of the law of increasing returns is also of great importance. For the same reason that when traffic increases, only a portion of the expenses are affected, it follows that, when business declines, only a part of the costs can be lopped off. In other words, a reduction in the volume of traffic does not in itself alone lead to a corresponding reduction in the operating expenses. Of course, many of these latter may, as we have seen, be temporarily postponed, as they were in 1893-1897, especially in the group of maintenance-of-way expenses. In such an event they must ultimately be made good by extraordinary outlay at some later time. But, unless they be thus postponed and unless the rates charged for service be reduced in order to stimulate traffic, it is inevitable that the margin of profit will drop as rapidly as it tends to rise with increased volume of business. This may be illustrated by the following computation.[52] Assume the total revenue from a given business to be $100, and assume it to be distributed as before, viz.: