In recent years, railroads have been combining with each other, merging into supersystems, causing heightened concernsabout monopoly. As recently as 1995, the top four railroads counted 1for under 70 percent of the total ton-miles moved by rails. Nextyear, after a series of mergers are completed, just four railroads will 2control well over 90 percent of all the freight moved by major rail carriers. Supporters of the new supersystems argue that these mergerswill allow substantial cost reductions and better coordinated service. 3Any threat of monopoly, they argue, is removed by fiercecompetition from trucks. But many shippers complain that as heavy 4bulk commodities traveling long distances, such as coal, chemicalsand grain, trucking is too cost and the railroads therefore have them 5by the throat. The vast consolidation within the rail industry means that the 6most shippers are served by only one rail company. Railroads typically charge such "captive" shippers 20 to 30 percent more than they do when another railroad is competing for the business.Shippers whom feel they are being overcharged have the right to 7appeal for the federal government's Surface Transportation Board for 8rate relief, and the process is expensive, time-consuming, and will 9work only in truly extreme cases. Railroads justify rate discrimination against captive shippers in 10the grounds that in the long run it reduces everyone's cost. If railroads charged all customers the same average rate, they argue, shippers who have the option of switching to trucks or other forms of transportation would do so, leaving remaining customers to shoulder the cost of keeping up the line.