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Laboratory, Japan

Terada N.,Signalling Systems Laboratory | Toyama T.,Signalling Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

Formal methods has been expected to increase the reliability of software, including that of signalling systems. In order to further the use of formal methods in the railway signalling domain, it would be beneficial to show examples of models of various signalling equipment using formal methods. As some examples, the specification of automatic block systems for single lines was modeled using formal specification languages, and the effectiveness of the model was verified by means of theorem proving and satisfiability problem solver. For theorem proving, B-method was used, which is characterized by theorem proving and stepwise refinement. B-method yields a very powerful result as far as safety is concerned, but it requires a high level of effort. On the other hand, satisfiability problem solvers can easily find truth of the proposition composed with many variables, but some restrictions apply in terms of the proposition domain.

Nagamine N.,Signalling Systems Laboratory | Ukai M.,Signalling Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

An obstruction-warning signal is an important piece of signalling equipment used at level crossings in Japan. However, it is not possible to check the visibility of such equipment during train operating hours, because this would require service disruption. This paper therefore proposes a method which employs near infrared LEDs, and can check the visibility of obstruction-warning signals during in-service hours. It has been proved that the developed image processing method, using a near infrared camera and a pan-tilt camera by feedback control installed on a vehicle, can correctly detect specific signal blinking. The paper then gives results from functional field tests.

Arai H.,Signalling Systems Laboratory | Fujita H.,Signalling Systems Laboratory | Ono Y.,Signalling Systems Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2012

The development of the effective and economical lightning protection measures is very important for railway signalling systems because lightning damage causes railway transportation disruption. This paper proposes a calculation model for lightning overvoltages on railway level crossing equipment. The calculation model consists of a propagation model of lightning surge along the rails and an equivalent circuit model of equipment. The authors validated the calculation model by comparison with field test results. This model is applicable for quantitative estimation of lightning protection measures of railway signalling equipment.

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