ABSTRACT
Railway networks are ubiquitous in today’s world and they continue to play a dominant role in transporting freight and people since 1825 when the first common carrier railroad was introduced. While countries with larger geographies such as the U.S., Russia, China, India, and the EEC benefit most from extensive and cost-effective railway networks, in many smaller but densely populated countries with large financial resources such as Japan, railway networks contribute significantly to the well-being of the national economy by efficiently moving workers and goods. As of 1987, the U.S. [14] maintains a total of 249,412 miles of railway tracks. It supports a total of 1,249,075,534 locomotive unit miles in one year to carry freight utilizing 5,989,522 loaded cars. For passenger services, the total unit miles stands at 3,782,470 while carrying the gross ton-miles of 1,357,097. In Japan, the East Japan Railway Company [15] carries a total of 16 million passengers each day on 12,000 scheduled trains and 7,500 kms of railway track. For efficiency, modularity, and safety in general, the tracks are divided into individual units, each of which may be controlled exclusively by the system. Thus, a train in propagating from location A to another location B may travel over several tracks. Given that two or more trains may compete, at some time instant, for the same track and that only one train may occupy a track at any time, the principal goal of the railway network management system is to allocate tracks to trains such that (i) collisions are avoided and (ii) the resources are utilized optimally.
