LOS ANGELES (AP) — Train driver Roman Alarcon is still haunted by the memory: He was working the morning commute when, suddenly, a man walked onto the tracks — and just stood there.

Alarcon laid on the horn and hit the emergency brake, but his train was still going about 20 mph when it hit the man and killed him.

Most transit agencies don’t talk about suicides, worried they might encourage copycats. But Los Angeles County Metropolitan Transportation officials, alarmed by an increase in people killing themselves by stepping in front of trains, made a rare appeal Monday and asked the public to extend support to people who might be at risk — before they make it onto the tracks. And there was another message, directed at those contemplating suicide: Consider the effect on the driver.

Struggling with feelings of helplessness and the horror of killing someone, it took Alarcon several months to talk about that day with colleagues. Eventually, though, he took on the role of sympathetic listener for other LA Metro train drivers who were unwilling accomplices to someone else’s suicide.

“We have to live with this the rest of our lives,” Alarcon said.

Since the beginning of last year, seven people have killed themselves on the Blue Line, which traverses some of the county’s poorest areas on its 22-mile route between downtown Los Angeles and Long Beach.

Before the recent increase, suicides had averaged one per year since the line opened in 1990, according to Metro spokesman Marc Littman. Alarcon was a Blue Line driver in 1994.

“We’ve reached the point where we must appeal to and engage the public” LA Metro spokesman Marc Littman said.

It’s hard to judge whether the increase in suicides on this one route is more than an anomaly.

Nationally, suicides in which someone was hit by a subway or light rail train peaked when 74 people killed themselves in 2011, according to federal data. The total dipped back to a more typical 55 people in 2012. New York City subways stand out as the transit system with the most suicides, according to the data.

LA Metro has taken steps to decrease suicides, among them installing emergency phones on platforms and sending retired bus and train drivers to Blue Line stations to intervene if they safely can.

One of these “safety ambassadors,” Theartis Blue, stopped women from taking their lives in both May and July, both at a station in the Watts neighborhood.

The first woman lay down on the tracks, and Blue was able to scoop her up before a train arrived. The second was on the platform, “trying to time” a train’s arrival when Blue moved her away.

Both were middle aged and distressed over their family situations, according to Blue, who retired as a bus driver in 1992.

“Life is something that is precious,” Blue said. “I was trying to explain that.”