(5) _Net income per mile._ Net income is obtained by subtracting from gross earnings operating expenses (and sometimes taxes) and adding to the net earnings so obtained whatever income from other sources the railroad may derive. This is a very important figure. As with gross earnings, the reports should be examined to determine whether net income is on the increase or the decrease, and it should be compared with the net income of other railroads occupying the same field. It involves a criticism of operating expenses. The payments of the railroad must be analyzed to determine whether the proper sums have been expended for maintenance of way, replenishment of rolling stock, and other improvements sufficient to keep the road in good physical condition. Normally speaking, operating expenses should absorb about 65 per cent of gross earnings. If it is found that a railroad operates for 60 per cent, however, it does not always follow that its operating officials are exceptionally efficient, so that the cost of conducting transportation is relatively small; it may mean that the physical condition of the property is being neglected, or that ordinary improvements, which should be charged to maintenance, are being paid for by increase in capitalization. It is very important for the investor to find out which is the case. If analysis leads to the suspicion that the earnings result from neglecting the property or capitalizing every trivial improvement, the railroad's bonds should be rejected. Net income varies from $1,500 to $12,000 per mile, with an average of $4,702. (6) _Fixt charges per mile._ The fixt charges of a railroad include interest on its bonds, rentals, and taxes (when the last-named are not reported with operating expenses). The importance of this figure lies in its relation to net income. If a railroad does not earn well over double its fixt charges, its obligations can not be regarded as in the first investment rank. Of course, when a railroad earns more than twice the interest requirement upon its entire bonded debt, it is probable that some of the underlying bonds are protected by three, four, or five times the interest requirement upon them, and their position is correspondingly strengthened. The foregoing analysis applies particularly to mortgage bonds upon the general mileage of a railroad and not to such special issues as collateral trust, terminal, bridge, or guaranteed bonds. It will not be necessary, however, to lay down any rules as to these classes of bonds, for the general principles outlined above, with slight modifications of detail, will be found equally applicable to a judgment of their value. Equipment bonds, on the other hand, owing to their want of similarity to any other railroad issues, will receive separate treatment later. It is of interest, in view of the present diminished confidence in railroad securities, to advance certain considerations touching upon the safety of railroad bonds in general.