In the study presented in this paper, calculation of the contact patch between a measured wheel tread profile and a designed rail shape carried out strictly by using a general software program called TED/CPA in order to investigate their contact characteristics. A calculation method to obtain the creep coefficient was proposed focusing on a contact patch subject to multi-point contact. This proposed method was then applied to contact conditions between the measured wheel tread profile of a commercial vehicle and the designed rail shape. Results showed that the contact patch shape is composed of many contact areas due to wheel tread unevenness, and the estimated creep coefficient may be smaller than the Kalker's theoretical value.

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Reducing the braking distance is very important to improve the safety of a railway system. However, increasing braking force to achieve this often causes wheel slide under wet conditions because the adhesion force between the wheel tread and rail governs braking performance. This has led to the development of a number of methods including "Anti-skid (Anti-lock) Brake System (ABS)," "Wheel Slide Protection system (WSP)," etc,. This paper proposes an advanced WSP using a new algorithm to detect wheel slip to achieve a higher level of performance than current systems. We also show the effectiveness of the proposed method by means of line tests.

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Rotation of wheelset(s) with small mass imbalance can induce relatively large carbody vibration and worsen ride comfort. Since the excitation force due to an imbalanced wheelset is transmitted from bogie to carbody through a traction link, the authors have developed a displacement-dependent rubber bush for traction links, which has a small gap between the rubber and the inner fixture to prevent this excitation. Unit testing of the rubber bushes to check their stiffness and durability, excitation tests using a full-scale test vehicle to verify the vibration isolation performance, and running stability testing with a bogie, have been carried out. A series of running tests on a commercial line were then conducted and the effectiveness of the displacement-dependent rubber bush was confirmed under actual service condition.

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Deteriorated track-slabs have been so far found in some areas subject to cold weather conditions. For track-slab maintenance purposes, it is very important to understand the causes of this deterioration. Visual inspections of track-slabs and investigation of samples of materials used in track-slabs were therefore carried out. Visual inspections found that deterioration occurred more frequently on south facing sides of track-slabs exposed longest to the sun. Material investigations showed that track-slab deterioration was caused by an alkali-silica reaction and frost damage.

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The authors performed shaking table tests to evaluate the aseismic performance of ballasted track by using full-scale models. The test results showed that in the case of ballasted track with no countermeasures, the amplitude of lateral displacement and the residual displacement increased because the lateral resistance of ballasted track significantly decreased when the earthquake acceleration acting on the ballasted track exceeded around 800 gals. Furthermore, the authors concluded that the decrease in lateral ballast resistance force could be prevented by applying adequate countermeasures against track buckling.

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Accurately analyzing the propagation of transverse cracking which causes rail failure is important to ensure train operation safety. Crack propagation until now has been analyzed using methods such as the Finite Element Method (FEM). These existing methods, however require the subdivision of meshes to be executed every time a crack is to be analyzed after new propagation. This paper proposes a crack propagation analysis method using the Boundary Node Method (BNM). The development of the BNM program for 3-D elastic analysis is presented here along with the results of some of its transverse crack propagation analyses.

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In order to identify effective measures while confronted with limited time and budgets, priorities must be set according to the purpose and effect of a measure. The authors developed a "Human Error Risk management method". This is a method for evaluation which considers "the level of influence of the error-inducing factor" on a risk value evaluated by the combination of "possibility of being of an error" and "worst accident probable to occur due to the error". Consequently, a method for management of human error prevention is presented, which can be adopted by a rail track maintenance office. This paper introduces an example of its application to track maintenance.

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A survey of drivers showed that the level of satisfaction in relation to driving positions varied significantly with body size. Eye height was determined as the most important factor to be considered in adjusting driving positions. In order to provide proper driving positions for a wider range of body sizes, a proposal was made to have a design based on a suitable eye height and distance to control handles. Evaluation of example layouts showed an improvement on existing layouts.

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"Human simulation" has been one of the major keywords in recent human science studies. This paper reviews human simulation methods applied to railway ergonomics. One type of simulator uses virtual reality technology to simulate an environment, such as Driving Simulators, Ride Comfort Simulators and Railway Station Simulators. Another type uses computer simulations to deal with topics such as (i) evaluating the mental workload experienced by train drivers and (ii) motion patterns of passengers and injuries caused by train collisions.

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