_Where the time table is so arranged as to call for speed nearly equal to the full capacity of the engine, it is very obvious that the risks of failure in “making time” must be much greater than at reduced rates; and when they do occur, the efforts made to gain time must be correspondingly greater and uncertain. A single example will be sufficient to show this_:—
_A train whose prescribed rate of speed is thirty miles an hour, having lost five minutes of time, and being required to gain it, in order to meet and pass an opposing train at a station ten miles distant, must necessarily increase its speed to forty miles an hour; and a train whose prescribed rate of speed is forty miles an hour, under similar circumstances, must increase its speed to sixty miles an hour; in the former case it would probably be accomplished, whilst in the latter it would more probably result in failure; or, if successful, it would be so at a fearful risk of accident._
_But a failure in either case would have the effect of retarding the movement of the opposing train, deranging the time of those of the same and of an inferior class in both directions, involving, perhaps, on the part of the latter, the necessity of similar struggles for time, and thus may prove the primary cause of accident to all trains whose movements may have been affected thereby._
The first cost of locomotives, (assuming the cost to increase with the weight,) is thirty per cent. greater for express trains, than for those of the second or third class.
The cost of repairs being assumed as the product of the weight by distance run, and this distance being the same, is as the weight, or increased thirty per cent. (This assumes the power to be equally well adapted.)
The cost of cars does not (though it ought), differ much for express or slow trains; the cost of repairs will certainly be increased.
The interest of construction capital to be charged to expresses, will be, their mileage proportion plus any expense which may have been incurred in reducing curves and grades; the proportion of repairs of superstructure, charged to expresses, will depend on their weight. The locomotive causes 25/29 of the wear of rails, and as the weight of the engines is increased thirty per cent., the increased wear will be of 15/58.