CCTV footage has been released of a woman with a pram dashing across a level crossing just before a train arrives.
The video, at a crossing in Llanelli, Carmarthenshire, shows her running across before barriers come down.
According to Network Rail, level crossings in the town are among the most misused in Wales.
It said there were over 140 incidents of motorists and pedestrians ignoring warning signs in the past six months.
As part of a safety campaign officers will be stopping people crossing the track throughout Tuesday to talk to them about safety concerns and handing out leaflets called "Would it kill You to wait?".
Police said most near misses involved local people taking a risk.
The safety drive is part of Network Rail's Don't Run the Risk campaign and coincides with an international day to highlight the dangers of people ignoring warning signs.
The company's community safety manager Alan Milne said: "We have a good safety record in comparison to many other countries but even one death is one too many.
"Jumping the lights and ignoring warning signs is sadly a sight we see all too often. Level crossings are safe, but if misused, they all pose very real risks."
It is being supported by British Transport Police.
Pc Phil James said the aim was "to educate drivers to use level crossing safely at Llanelli and across south Wales."
He added: "Around 95% of the people who are caught and prosecuted for misusing level crossings live in the local area and have used the facility many times.
"It is often this familiarity that causes the problem.
"We would urge all users to comply with safety rules and use level crossings correctly."
"BTP will take positive action against all drivers who fail to stop at the crossing lights or misuse crossings in any other way, and many can expect a substantial fine, court costs and penalty points on their driving licences."