Milestones:Railroad Ticketing Examining System, 1965-1971
Railroad Ticketing Examining System, 1965-1971
Osaka, Japan -- Dedicated 27 November 2007 -- IEEE Kansai Section
Pioneering ticket examining machines, designed to speed commuter railroad use substantially, were first installed in 1965, based on work by a joint research team of Osaka University and Kintetsu Corporation. Following this work, an improved version – based on joint work by Omron, Kintetsu, and Hankyu Corporations using punched cards and magnetic cards – was first deployed in 1967 and at nineteen stations in 1971.
In Japan, the 1960s were called the “Golden 60s”. Economic growth and equipment investment growth were 13.4% and 40.9%, respectively. The gross national product of Japan grew to the third largest in the free world in 1967 and to the second in 1968.
The number of commuter passengers increased at an accelerated pace, and more than 50% of the day's total was concentrated in a very short time of morning rush hours; the number of passengers passing through an examiner-assisted exit gate reached 75-80 per minute. Because of the limited number of platform personnel, the queue of passengers at each exit gate continued to grow seriously.
To examine the commutation tickets in rush hours, a high speed examining machine for the commutation tickets was needed. In the early 1960s, there were few automatic examining machines in public service in the world, all of which were the so-called "closed-gate" type. As of 1965, the latest examining machine was of four-door type, in service at London Transport and Illinois Central Railroad. This machine was developed only for single/multiple ride tickets, and hence it could not read the more complex commutation tickets widely used in Japan. The examining speed was at most 15-20 passengers per minute, too slow to cope with such heavy congestion.
The investigation commission studied the technical problems of developing a novel examining machine not only to read commutation tickets, but also to make the examining speed be several times as fast as that of the conventional one. At that time, however, the IC (Integrated Circuit) technology was not yet available. The commission confirmed that the new automatic examining machine had to be constructed by means of transistor logic.
A joint research team of Osaka University and Kintetsu Corporation, devised a graph theoretical approach to encode each passenger's route with the shortest bit length, and to check whether or not the stipulated route of a ticket covered the station at which the ticket user entrained or detrained. The objective was to make the code as short as possible and also the logic architecture of checking route validity as simple as possible.
To this end, the joint research team constructed a tree-based encoding scheme for stipulated routes, by which the path encoding was achieved with the use of 21 bits, and a bitwise comparison arithmetic for checking route validity. This was performed by checking the validation of a few inequalities formulated with the use of the code of a given stipulated route and the code of a station.
Kintetsu railroad network was composed of 280 stations. 170,000 possible routes were enumerated, and it was determined that at least 18 bits were necessary for encoding all possible routes. Eventually, by introducing only three redundant bits in the path encoding, the route validity checking could be performed by executing a few comparisons between binary numbers.