In order to shorten the travel time of limited express trains operated between Sapporo and Kusiro in Japan, a tilting diesel car called series DC283 (passenger car for a limited express train) with forced steering bogies (DC283 forced steering bogies) has been developed by JR Hokkaido and RTRI. This paper describes the lateral force between wheel and rail observed with this test car on curve and that obtained from coresponding computer simulations. The results of simulations and field tests are as follows. (1) DC283 forced steering bogie can reduce the lateral force between wheel and rail. (2) The decrease of the lateral force due to the forced steering bogie should be verified not only on circular curves but also on transition curves. (3) The lateral force of the first wheelset is the largest. (4) To decrease the lateral force more effectively, the steering ratio is set 35 percent (Lv=1.35) higher than the value that makes the radial position. (5) The running stability at the maximum speed of 140km/h is satisfactory in field tests.

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This report shows some measurement results of the flexural vibration of actual railway vehicles and presents a new analytical method to investigate the vibration. Stationary vibration tests show that recent lightweight railway vehicles often have complicated three-dimensional (3D) vibration mode shapes. A new analytical method is proposed to simulate and study measures to reduce such complicated vibration. In this method, the carbody is modeled as a box type structure consisting of plates and beams. The condition to connect components is satisfied by introducing artificial springs at their joints. The formulation procedure of the method to analyze natural modes and frequency response to vertical track irregularities are described in brief. The numerical results are compared with the measured data for an actual railway vehicle to examine the validity of the method.

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For the traction motor control system, pulse generators (PGs) are used to detect the rotor frequency of induction motors. If speed-sensor-less control is applied to the traction motor control system, the PGs can be eliminated to improve the cost efficiency and reliability of the traction motor control system. In this paper, the author present the results of theoretical and experimental studies on the application of the speed-sensor-less control method to the railway vehicle traction motor control.

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Serious railway accidents in recent years in Japan were surveyed in order to clarify the target of railway crashworthiness. From the result, it was found that level crossing collision accidents were one of the most important targets of the crashworthiness of railway carriages. Both numerical simulations and empirical method to analyze crushing behaviour of railway carriages in Japan were applied in this research work. As the empirical methods, quasi-static compression tests for carbody sections were used to understand crushing behaviour of the carbody. Using the crushing characteristics obtained from the test, one-dimensional lumped mass numerical model was built and calculated to evaluate impacting behaviour of the trains at collision accidents. Three-dimensional FE analysis and real size train crash test were also included in this research program. The results of both numerical method and experimental tests were compared.

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Electric railway vehicles now use regenerative braking for normal operation from the top speed to almost zero. For regenerative braking, the terminal voltage of the traction motor cannot be exceeded in the limited catenary voltage and the withstand voltage of semiconductor device. Therefore, the electrical brake force in the high-speed range is smaller than that at medium or low speed and the total brake force in the high-speed range mainly depends on the mechanical brake. By inserting rheostats between the inverter and traction motors, the regenerative brake force can be increased in the high-speed range without increase of the rated power and current of inverter. We studied the possibility of increasing the regenerative brake force by rheostats. The effectiveness of the proposed method is verified by test-bench experiments.

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Recently labor saving for train maintenance has been strongly requested. This requires that train air hoses serve for longer years. Current air hoses have several weak points such as the cover rubber is not so tolerant to sunshine (ultraviolet ray), ozone and heat caused by direct exposure to sunshine. The reinforcing fabric is also not so tolerant to shock from the collision of small hard particles such as ballast. To overcome these problems we have developed two types of long-life air hoses made of synthetic rubber and fabric that feature high durability. As a result of accelerated deteriorating tests both types of newly developed hoses are presumed to withstand service for more than 13 years.

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A number of developing countries will increasingly become rich in the 21st century together with developed countries, to consume much more energy in the life of people, and for production and transport. Railways are expected to play an important role in high-speed passenger, commuter, suburban and freight transport. If the share of railways is enhanced, energy consumption and emission of CO₂ will be cut in the field of transport. To have the railway transport accepted more positively by people, it is important to ceaselessly develop rolling stock technologies to improve the convenience of users, reduce noise and vibration, save energy and establish EMC and reliability of the railway system.

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