A man waiting for the subway fell on the track in front of the train and Noh slammed the brake. Fortunately, the man survived because he had dropped between the rails.

The man, who was rushed to hospital and treated for injuries which were not serious, said his fall was an accident but Noh feared it was a suicide attempt.

Suicides and accidents on Seoul's vast subway network have been increasing sharply, claiming nearly 70 lives last year and causing post-traumatic stress or worse among subway drivers.

Noh told The Korea Herald he was unable to drive a train for a number of days because the accident kept flashing across his mind.

"Whenever the memory of the accident hit me, I tried to forget it. If I cannot do that, I can never drive again," he said.

Though Noh has now put the incident behind him, many subway drivers have suffered post-traumatic stress and even panic disorder.

Last September, a 33-year-old driver, who gave his family name only as Kim, felt the urge to jump from the subway he was operating. His blood pressure soared and he started to vomit.

The hospital diagnosed Kim's illness as panic disorder. He applied for Workmen's Accident Compensation Insurance and was granted it in February by the Korea Labor Welfare department - the first time the government has considered and granted such a payment as the accident occurred during working hours.

Two other drivers who underwent medical treatment for similar symptoms committed suicide last August.

Six other drivers operating trains when suicides or accidents occurred were reported to be suffering post-traumatic stress. The labor union of Seoul Metropolitan Rapid Transit Corporation says the six are also victims of panic disorder and recently applied for Workmen's Accident Compensation Insurance on their behalf.

SMRTC management said there were no drivers seriously afflicted with panic disorder in the company.

"Everybody can be taken ill with panic disorder. Whether you get panic disorder or not is hereditary. To experience an accident is not the decisive factor of getting panic disorder," said a corporation official who wanted to remain anonymous.

"We assign any locomotive driver who is under severe stress after an accident to another post, if he wants," he added.

Many drivers cannot easily forget accidents. Kim Ki-tae, a train operator for more than six years, told The Korea Herald about his problems after a man jumped onto the track in front of a train he was driving in mid-January and was crushed to death.

"I rested for three days after the accident. But even these days, the wretched scene of the accident flashes in my mind whenever I drive to the very spot where the accident took place," he said. "I have to drive my train to the same place four times a day."

A study by Seoul Metropolitan Subway Corporation said 119 people fell or threw themselves onto subway tracks last year. Of these, 67 died and the others were seriously injured. Among the dead, 54 were suicides.

Subway track incidents rose 55.8 percent from 2001 to 2002 and 52.3 percent from 2002 to 2003.

According to the survey, people in their 20s were the most frequent jumpers and experts said the reasons were mainly difficulties in finding jobs or failure to get into universities.

Experts cautioned that some who try to commit suicide by jumping in front of a subway train could end up hospitals for the rest of their lives. Last week, a woman in her 20s fell from the subway platform in Daegu as a train was arriving. She suffered severe face injuries and her left leg was amputated.

Train drivers Noh and Kim said their hearts palpitate as they drive their trains into stations, fearing someone might fall or jump onto the tracks in front of them.

"We slam the brake if we see someone who is likely to fall from the platform. However, unlike cars, a subway train cannot stop immediately because of its speed and heavy weight," Noh said.

"In the worst cases, the train stops after about 200 meters, crushing anyone who has fallen in front. Imagine how we drivers feel after such an accident."

Apart from suicides and accidents, the working conditions of subway drivers are another factor of panic disorder, experts said.

They operate their trains in long and dark tunnels all day long. Though there are two light bulbs in the driver's cabin, the area is never really bright, and that can be disorienting.

One driver interviewed by the Weekly Hankuk said he sometimes felt like a prisoner confined in a dark, suffocating jail.

Irregular working hours make conditions more difficult. Sometimes, drivers are on duty from 6:30 a.m. to 10:30 p.m. because of extended subway service hours.

They have to operate their trains to specific schedules to avoid congestion and driver Kim said, "It is one of the most difficult parts of this job." Also, getting to a rest room while on duty is impossible.

Yoo Sang-woo, chief director of Mental Health Clinic Yoo & Kim, warned that while a driver who experiences an accident may seem alright at the time, panic disorder symptoms could appear any time in the future.

"The symptoms are similar to heart disease or palsy. However, the panic disorder does not cause danger to one's life. But it may cause complications such as depression," Yoo said.

Anyone with panic disorder must be put under medical care. In most cases, medical therapy and psychological therapy are required simultaneously, he added.

There have been many calls for more safety devices to prevent suicide attempts and accidental falls onto tracks. Seoul Metropolitan Subway Corporation official Kang Sun-hee said the government would put up more railings on subway platforms.

"We will increase safety measures. We will watch the increased number of CCTVs more thoroughly and develop a monitor system to prevent people falling from subway platforms," Kang added.