From the Nov. 17, 1907 NYT:

The Directors of the Interborough-Metropolitan Company have come to recognize that the loss of fares due to dishonesty of conductors and their failure to collect is the most important factor with which they have to deal in reorganizing the surface railways of Manhattan and the Bronx. This realization...is one of the reasons why the...managers...look with particular interest for the coming trials of the Montreal, or pay-as-you-enter car, on the Madison Avenue line, for this car is supposed to make dishonesty on the part of conductors as near an impossibility as anything can be when a mere mechanical device is pitted against human ingenuity...

Several months ago there was a case in the divorce courts which opened the eyes of a good many of the Interborough-Metropolitan Directors who had not previously looked into this phase of the situation. The wife of a New York City Railway conductor was suing for alimony, and in her bill allege that, although her husband's salary from the company was but $18 a week, he ought to pay alimony on $50 a week basis, as he "knocked down" $35 a weak on the side...

Various statements of what this system of graft was worth to individual men have been made up, but only as estimates. One man high up...said yesterday that a former valet who was put in on the road as a motorman found that his share of the daily graft was from $2 to $3 under normal conditions.

It is explained...that it is wise for a conductor to have a motorman in his confidence, inasmuch as the latter is in a position to "drag" the car - that is, make it get behind on its schedule sufficiently to fill up very full of passengers. Knocking down fares is a easier matter in a crowded car than it is in a relatively empty one where passengers can see the cash register.

An interesting principal-agent problem with a potential solution.