A Study on History of Rolling Stock Door Engines of Seoul Metro Line No.3 and No.4

3,4호선 도시철도 전동차 도어엔진의 개발 역사에 관한연구

It is said that the number of people using public transportation has risen about 220 thousand over 3 years which was 1019 people average a day in 2006 and 1041 people last year. It is also said that the number of people using subway has increased by 198 thousand and the number of people using bus by 22 thousand. Can you imagine how many door engines work at the same time if we count Metro line no.1 to no.4 which consist of total 120 subway stations? A train has 80 door engines and Metro line trains have 9600 door engines all together. Which explains it quite simple how much Satefy, Durability and Sustainability need to be focused in Door Engines. Although it's not the whole part of door engines in Seoul Metro Line, And Metro No.4's door engines are operated by the method called mixture of mechanical type and belt type. And the last one is being used in the brand-new Metro train line No.3 which is being operated by electricity motor, instead of the old methods which use air pressure to operate a door engine. I'm sure you will agree that Safety is the first priority of Metro train and next follow comfortability and quickness. I think all I've talked so far make it the first step for the Safety of Metro train for you to understand the unit of a Door Engine.