South Korean residents have expressed worry over the worsening safety level of transport facilities in the country as another tragedy struck on Friday afternoon just two weeks after a ferry sunk, killing more than 200 passengers.

Reports said that an eastbound subway train on the Seoul Metro line No 2 that left Sangwangsimni Station in Seongdong District was hit on its rear by another train at 3:30 pm.

Over 200 passengers were injured by the incident which caused two coaches at the end of the lead train to detach and derail.

Dozens of ambulances arrived at the station within minutes of the accident, rushing over 170 injured travelers to 12 medical centres.

The rest of the over 1,000 passengers from the two trains had to open the coach doors manually and walk on the platform or down the rail tracks. Other nearby trains on the same line headed for both directions were stopped, but operations of westbound trains were later resumed at a slower pace.

Due to the accident, transport authorities added more buses that pass by Sangwangsimni Station.

Jeong Su-yeong, official of Seoul Metro which is holding an investigation into the incident, said upon questioning, the driver of the train that rammed the first train said the "clear" signal suddenly turned "stop" but hitting the first train could not be avoided because of the very small gap between the two trains.

Because of the accident, the Ministry of Land, Infrastructure and Transportation organised an emergency task force following technical problems encountered by Seoul subway lines in the past few months.