It is very essential that men engaged in the movement of railway trains, and in the quick reading of signals, by day and by night, should have such acuteness of vision as will enable them to correctly read the signals in use at the necessary distance; such perception of color that they will not, under any of the varying conditions of service, mistake a red signal for a green, or vice versa; and good hearing.
On the head end of a train it is important that these essentials should be found in even a higher degree than will suffice for the safe performance of duty in other branches of the service, and the question arises, what are the standards that should be required for the different branches of the service, and what are the best and fairest methods of examining men to make sure they come up to these standards.