Abstract

Abstract Overview

This study focuses on how the electromagnetic environment within subway vehicles can be affected by high-power devices and different materials, potentially impacting the operation of the vehicle and the health of sensitive passengers like those with pacemakers or defibrillators.

Research Objectives

• Examine low-frequency magnetic field distribution characteristics in various subway train setups.
• Analyze human exposure to electromagnetic fields, particularly in relation to different subway construction materials and the presence of Wi-Fi device emissions.

Methodology and Findings

Nephograms depicting magnetic flux densities were calculated for subway trains composed of different materials, with and without windows, and with added shielding layers.

• The stainless-steel carriages show lower average magnetic flux density compared to aluminum alloy and CFRP carriages.
• Removal of windows led to a decrease in average magnetic flux density.
• The presence of a shielding layer reduced magnetic flux density from 10.5 uT to 3 uT.
• Under various conditions, the maximum magnetic flux density observed was about 10 uT, significantly below the ICNIRP limit of 0.1 mT.
• The highest SAR in human tissue was 0.00749 W/kg when exposed to Wi-Fi, also below the IEEE exposure limit of 1.6 W/kg.

Conclusion

The findings suggest that modifications in carriage materials and structure, as well as the strategic use of shielding, can significantly reduce magnetic flux density and potential health risks related to electromagnetic fields in subway environments.