New track measurement method using angular velocity and lightweight track geometry measuring trolley

For measurement of track geometry, the differential method or the inertial measuring method is used. In 2016, we developed a track measurement method that does not belong to either ofthem andnamed it as the differential difference method. This new measurement method uses the angular velocity measured by a gyroscope and does not require complicated strapdown calculation for determining the attitude angle. We assembleda compact track measuring trolley and check the accuracy of measurement to evaluate the effectiveness of the differential difference method. As a result, the method showed significantly superior repeatability compared to the conventional device. In addition, it can be zero-adjusted within several seconds, does not require any movable partfor measurement of longitudinal levei and alignment, and only weighs 13.4kg. Therefore the differential difference method is considered to be a superior track measurement method that contributes to cost reduction, weight saving, improvement of usability and maintainability, and so on. © 2020 Japan Railway Engineers' Association. All rights reserved.