• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.8
• /
• pp.459-467
• /
• 2016

In order to assess the pollution status and distribution characteristics of PM and PM-bound species, PM10 samples were collected using mini-volume air sampler at the subway cabin in Daejeon city. Measurements of about 24 elements including toxic metals (e.g., As, Cr, Mn, V, Zn) in PM10 were made by instrumental neutron activation analysis and X-ray fluorescence. The average PM10 concentration was $59.3{\pm}14.5{\mu}g/m^3$ in the subway cabin with a range of 42.2 to $97.4{\mu}g/m^3$, while the associated elemental concentrations were varied in the range of $10^{-3}$ to $10^5ng/m^3$. It was found that the concentration of Fe ($12.5{\mu}g/m^3$) was substantially higher than any other element. The Fe concentration was apportioned by about 20% of the PM10 concentration. The results of factor analysis indicate that there are no more than six sources in the cabin (e.g., brake-nonferrous metal particle, resuspended rail dust, fuel combustion, vehicle exhaust, black carbon, Cr-related).

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.2
• /
• pp.64-79
• /
• 2023

This study reviewed the process of applying the Monte Carlo simulation technique to the traffic allocation problem of metropolitan subways. The analysis applied the assumption of a normal distribution in which the travel time information of the inter-station sample is the basis of the probit model. From this, the average and standard deviation are calculated by separating the traffic between stations. A plan was proposed to apply the simulation with the weights of the in-vehicle time of individual links and the walking and dispatch interval of transfer. Long-distance traffic with a low number of samples of 50 or fewer was evaluated as a way to analyze the characteristics of similar traffic. The research results were reviewed in two directions by applying them to the Seoul Metropolitan Subway Network. The travel time between single stations on the Seolleung-Seongsu route was verified by applying random sampling to the in-vehicle time and transfer time. The assumption of a normal distribution was accepted for sample sizes of more than 50 stations according to the inter-station traffic sample of the entire Seoul Metropolitan Subway. For long-distance traffic with samples numbering less than 50, the minimum distance between stations was 122Km. Therefore, it was judged that the sample deviation equality was achieved and the inter-station mean and standard deviation of the transport card data for stations at this distance could be applied.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.842-846
• /
• 2004

Both traffic congestion and air pollution in the metropolitan area can be greatly relieved by promoting the use of public transportation with zero emission system. Bus and subway are very convenient means for the people moving in the route areas. But they are not enough to satisfy handicapped or old people to have access to them and also do not solve environmental problems completely. New vehicle system, fuel cell track rapid transit, will be introduced as a countermeasure for such problems in the present paper.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.354-361
• /
• 1997

본 연구에서는 우선적으로 수도권 대량운송 수단인 지하철 전동차의 진동을 측정하고 인체에 미치는 영향을 평가하였으며 전동차의 진동특성이 인체 각 부위에 전달되는 형태를 분석.평가함으로써 승객과 승무원의 승차감 및 작업환경 향상은 물론 차후 개발되는 고속전철 및 비접지 차량(zero-ground pressure vehicle) 등의 개발에 필요한 기초자료를 제공하고자 한다.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1993.06a
• /
• pp.73-82
• /
• 1993

Ground-borne vibration is one of the main causes of environmental impact from subway systems. The vibration resulting from track-train interaction is transuutted through the tunnel structure and the surrounding ground to adjacent buildings. This paper provides a summary of proposed noise and vibration criteria, a review of the ground vibration propagation mechanism and the theoretical isolation effectivenesss of each of the following underground transit systems : track, tunnel and vehicle itself.

• Proceedings of the KSR Conference
• /
• 2002.05a
• /
• pp.61-66
• /
• 2002

As the technique in urban transit is composite system which is composed of vehicle, power supply, signal and communication, rail structure etc, it is very difficult to search the cause of technical troubles. This paper describes the improvement on pending issues which is discussed in urban transit corporation's conference. The conference for discussion on technical issues will be held every year, and the result of conference will be opened.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.44-48
• /
• 2005

In general, the parallel-connected linear induction motors(LIM) are fed by one VVVF inverter in the magnetically levitated vehicle(MAGLEV) or linear motor subway drives. The air gap length of the parallel-connected linear induction motors operating at a grade or curved sections can be different each other. The air gap difference of the two motors attached to the same module causes unequal phase currents, asymmetic thrust and attraction force generation. In this paper, parellel-connected linear induction motors are operated by one IGBT inverter under the different air gap condition so that the phase current characteristics are examined experimentally.

• Proceedings of the KSR Conference
• /
• 2002.10a
• /
• pp.281-289
• /
• 2002

This paper is described for the flame behaviors in light railway cabin by numerical simulation code, which can be interpreted the design parameters in terms of suppression the fire propagation and excavation the passengers safely. The results shows that the flame intensity(fire temperature, smoke density) depends on the firing points in cabin and propagates rapidly whole cabin space rather than modern subway cabin due to smaller inner space. The data will be used to how can be get the safety case, which is described on the operating principles for all facilities and logistics against to the light railway firing accidents.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.3
• /
• pp.679-686
• /
• 2018

A new dust cleaning vehicle is needed to remove fine and ultra-fine particulate matter in subway tunnels. Therefore, the recently developed tunnel cleaning vehicle is equipped with an efficient suction system and cyclone-based prefilter to handle ultra-fine particles. To treat various sizes of particulate matter with an underbody suction system, this paper proposes a cyclone-based prefilter in the suction system and validates the dust removal efficiency through Computational Fluid Dynamics (CFD) analysis using ANSYS FLUENT. Using the created surface and volume mesh, various particle sizes, materials, and fan flow rates, the particles were tracked in the flow with a discrete phase model. As a result, the dust cleaning vehicle at a normal operational speed of 5km/h requires at least a fan flow rate of $1500m^3/min$ and 100mm of suction inlet height from the tunnel track floor. Those suction modules and cyclone-based prefilters in the dust cleaning vehicle reduces the dust accumulation load of the electric precipitator and helps remove the accumulated fine and ultra-fine dust in the subway tunnel.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2928-2933
• /
• 2011

The urban railway has been planned not only the subway, but also the elevated railway in Seoul, South Korea. Therefore, it is steadily increasing civil complaints for railway noise passing through that residential district. In this paper, we focused on noise of squeal characteristics induced by interaction between railway vehicle's wheel and rail. Then we selected the point that carried out scattering water droplet to the rail and compared the noise level of the watering test results before and after. Scattering water test results showed that level of the noise reduced intermittently occurring high frequency characteristics of squeal noise as well as overall noise level. In the future, we will apply the sensor to the sprinkling system for noise reduction where the place of existing squeal noise is, and make a suggestion of this solution will be more economical, environmental-friendly, and appropriate to reduce the squeal noise occurred by railway vehicle than others.