Passengers Comfort Perception and Demands on Railway Vehicles: A Review

Trains are becoming a popular way of transportation driven by comfort and ecology reasons. Latest statistics showed an increasing of 40% on the number of passengers in the last decade. The development of new high-speed trains promoted an evolution on the coaches interiors, as to make railway transportation more attractive. To cope this objective, new requirements were set, namely high levels of comfort and safety. In complement, multiple long-term ride comfort evaluation methods have been developed. The aim of this work is to present a review on the passengers’ comfort perception in railway vehicles. The standards ISO 2631, EN 12299 and the Sperling’s method are the most used ones. They refer several factors, as the vibration (level, frequency and duration), temperature, noise and area of the train per capita. Additionally, the perception of reduced accidents delayed the studies of passive security. Therefore, recent works focus on reducing the consequences of the second impact in case of accident and minimize the biomechanics injury criterion, through new interiors design layouts. Keywords: Railway vehicles, Passengers comfort, Posture, Ride evaluation, Passive safety

Research Topics on Railway Vehicle Dynamics

Engineering research subjects relating railway vehicle dynamics are described as a literature survey in this paper. Research works concerning to the motion of wheelset; pantograph-catenary interaction; aerodynamic relating problems on the vehicle; and application of control techniques are introduced firstly as the most distinctive subjects of railway vehicle dynamics. The topics on safety assessment and ride comfort evaluation are also dealt with since those are important research area in railway dynamics as public transportation system. The subject concerning to carbody elastic vibration, which is important relating to ride comfort, is also described. The effect of passengers on the elastic vibration of carbody has been introduced as the interesting (and something surprising) topic. The focuses in the literature survey are particularly on the research works from Japan, in this paper.

An investigation on interior noise reduction using 2D locally resonant phononic crystal with point defect on car ceiling

Interior noise, as one of the indicators of automotive NVH (noise, vibration and harshness) performance, has been associated with an increasing importance in ride comfort evaluation. This paper presents a new method of interior noise reduction based on phononic crystal theory. Considering the lightweight requirement, the car ceiling plate is divided into nine regions to determine where the phononic oscillators should be mounted. By leveraging the acoustic contribution analysis of each region, the phononic crystal is arranged in the region that contributes the most to interior noise, bringing out the best attenuation effect in its bandgap. However, it is noted that at certain frequencies, the vibration of the ceiling plate or other body plates, which exhibits negative contribution to interior noise, should not be attenuated due to their beneficial effects. Thus in this paper, a point defect is employed for the design of a two-dimensional (2D) phononic crystal structure to preserve the negative contribution part of the plate’s vibration at specific frequencies. The validity of the proposed method in interior noise reduction is verified by simulation. Moreover, the error analysis is implemented and an optimization scheme is proposed.

Ride Comfort Evaluation Using Brain Activity in the Prefrontal Cortex Induced by Discomfort During Horizontal Vibration

In this study, we measured brain activity using near-infrared spectroscopy (NIRS) when a person was feeling discomfort caused by vibrations. We used the variance in oxygenated hemoglobin (oxy-Hb) levels as an evaluation index. Correlation coefficients were derived from the results of brain function measurements and sensibility evaluation of discomfort using a questionnaire. As a result, a high negative correlation was observed between discomfort and both vibration and brain activation around the medial prefrontal cortex, and a high positive correlation was observed between discomfort and both vibration and brain activation around the lateral prefrontal cortex. This suggests the possibility of evaluating discomfort on the basis of brain activation.