So much for the standard rates. Just as certain railroad lines running from New York to Chicago are permitted to charge two dollars less for tickets than other "standard lines," because of slower running time, so does the same factor make a "differential" in freight rates. Big roads boast that they can haul the first-class freight--the "preference freights"--from one city to the other in sixty hours. Others take a longer time, and are permitted by their larger competitors to make their prices a shade lower because of slower running time in freight service. Such a "differential" is the Grand Trunk, handling New York-Chicago freight by a roundabout route, from New York by water to New London, Conn., and thence over the Central Vermont up into Canada and the Grand Trunk's main line. Obviously such a longer route adds to the running-time and would be at a keen disadvantage in securing travel, without a lower rate as bait for the shipper. We have used New York-Chicago differentials simply as illustrative cases. The differentials are apt to be found in any corner of the country where there are long hauls and a number of railroads fighting to secure them. But the Grand Trunk as a factor in Chicago traffic to and from Boston brought one of the earliest and most interesting decisions from the Interstate Commerce Commission. St. Albans, Vt., complained to that board that its local freight rate by Boston & Maine and Central Vermont from Boston was higher than the through rate from Boston to Chicago. On the face of it, it seemed as if justice must have rested with St. Albans, but the railroad was able to prove its case and win a decision. It showed that it could not live on shipments between Boston and St. Albans and other local non-competitive points, or on the business interchanged between these points. To earn its bread and butter it must fight for the rich Chicago traffic; and to be in a position to fight for that traffic, despite some disadvantage of location, it must make very low rates. It proved that these low rates were possible for business that went through in solid trains, like Boston-Chicago traffic, and that each of these trains earned its proportion of the railroad's profit. For when you come to handle freight at St. Albans, more particularly the case in still smaller towns, you bring on a new traffic expense, and because of this expense we get what is known as "back haul."