Narrow Margin (1990) HD

Carol Hunnicut, a young divorcee, editor of a magazine, accepts a distinguished suitor's invitation to dinner, first going up for a moment to his luxurious apartment, as he has to take care of something urgent there. That luxury is the result of collaboration with an organization of criminals who are now extorting him, and Carol, terrified, involuntarily witnesses, unseen, the murder of the guest. Terrified by the doubt of having somehow been glimpsed by the killer or the instigator - a ruthless crime boss whom she recognizes - Carol takes refuge in a cabin in the mountains of Canada. Here she is joined by helicopter by Robert Caulfield, district attorney sent by the police with two agents to protect the woman, who is the only valuable witness to the crime. But the criminals have also identified her refuge, and they swoop in immediately afterwards. Having destroyed the police helicopter and eliminated the two officers, they chase Carol and Caulfield, who escaped the ambush and headed for the nearest train station. Once the latter also reach the station, they get on the same train behind Caulfield, who has just placed Carol in a reserved compartment. The hunt then continues inside the moving train, from wagon to wagon, from tunnel to tunnel, amidst reckless acrobatics and spectacular risks. In the end the killers are eliminated by Caulfield and the dangerous boss brought to justice.