It happens more than you might think: Once every three days, someone is struck by a subway train. But in a system as vast as New York City's, the chances of it happening still remain lower than the more improbable events of the imagination, even being hit by lightning.

One person was struck by a train for every 11.8 million riders who passed through turnstiles and into the subway system last year, according to a Wall Street Journal analysis of records from the Metropolitan Transportation Authority and state regulators. The chances of being hit by lightning? About 1 in 775,000.

The rate has remained relatively stable over the last decade, even as daily ridership has grown by 680,000—to 1.6 billion rides a year, the Journal analysis showed.

Even so, a recent pair of high-profile subway deaths have made commuters wary. The MTA said Monday it planned new safety measures after two men were apparently pushed to their deaths in separate incidents in December. Criminal cases are pending in both.

The agency already has enhanced station announcements to warn riders to stand away from the edge of the platform. New fliers—in English, Spanish, Chinese, Korean and Russian—will be rolled out across the city, as will an unusual paid-advertising campaign in local newspapers, MTA officials said.

The agency also is committing to investigate—though with no pledge to ultimately install—high-tech solutions to prevent people from falling or being pushed into the path of a train. Those include a pilot program to test the use of platform barrier doors on the L subway line, and a vow to explore the installation of an automated warning system that would alert train controllers when a person is on the tracks.

In the short term, the agency plans to try to convince customers to use caution on platforms, rather than speed the installation of platform barriers, said Thomas Prendergast, president of the MTA's transit division. Those barriers are expected to cost millions of dollars apiece, and they might not be easily adapted to use in the aging New York subway system.

"If you look at it in terms of order-of-magnitude costs and what it would compete against in terms of other safety improvements, it's a difficult argument," Mr. Prendergast said. "What we know we can do is we can focus efforts right now on trying to change customer behavior, and that's what we've been doing."

Last year, 141 people were hit by subway trains, 55 of them fatally. Of the total, 33 were believed to be suicides or attempted suicides, and another 54 were people struck on the tracks after being there for a variety of reasons, such as a deliberate leap off the platform to retrieve property or cross to the other side, or an accidental tumble in front of a train.

A police officer stands on a subway platform where one man was killed and another seriously injured in separate incidents just minutes apart earlier this month. One person was struck by a train for every 11.8 million riders who passed through turnstiles last year. Reuters

The fatal pushings prompted Manhattan Borough President Scott Stringer, City Councilmember James Vacca and some safety advocates to call on the MTA to do more on the issue.

Mr. Stringer, who is a candidate for city comptroller, issued an unusual news release about a failed suicide attempt after an individual leapt in front of an R train last weekend. He predicted that 100 people could die by being struck by subway trains in 2013 if the incidents continued to occur with January's frequency.

Still, the rate at which riders are hit by trains is only slightly above what it was in 2001, and well below its high from 2003, when 188 people were struck, 37 fatally. Last year, 85 people were struck by trains for every one billion passenger trips on the subway, slightly down from the previous year.

"Especially as ridership increases, we owe it to straphangers to ensure that the MTA is doing all that it can to responsibly maintain safety and reliability underground.""Six deaths and three serious injuries in any three-week period is cause for alarm," Mr. Stringer said.

—Tom McGinty contributed to this article.

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