The Dark Frontier by Eric Ambler

compartment firmly behind him. The first thing was to ascertain the whereabouts of the mysterious man and woman. If his conjectures had been right they would also be in the Roumanian coach bound for Zovgorod.
    Giving way to the movements of the train in order to render his progress as slow as possible without arousing suspicion, he started to walk the length of the coach. As he passed each compartment he glanced casually at the occupants. He had almost reached the end of the corridor and the conclusion that his theory was wrong before he saw them. They were in a compartment by themselves, the man apparently dozing, the woman reading a book.
    Carruthers did not pause and continued his way to the end of the corridor. There he stopped and, leaning on the handrail, gazed out of the window. By turning his head slightly he had an uninterrupted view of the entire corridor of the Roumanian coach: a few feet away was the entrance to the compartment of what he now felt practically certain was the Ixanian representative and his companion; beyond that, at the far end of the corridor, was Groom’s compartment.
    The train roared over a viaduct and into a cutting. Watching the embankment stream by, Carruthers considered his next move.
    Obviously, he must make the woman’s acquaintance, talk to her. But how? It was out of the question to reveal his true identity and business or even his imposture of Professor Barstow. He must, then, engage her in conversation as a fellow-traveller. It would not, he thought, be easy. She did not look the sort of person to encourage casual acquaintances. He considered several conceivable gambits only to reject them as clumsy and was still wondering how best to accomplish his purpose when Fate took a hand in the game.
    The train had left the cutting and entered a long tunnel. Suddenly, he noticed that it was slowing down. By the time it emerged it was moving at little more than walking pace, while from below came a continuous and penetrating grinding. A few yards more and the train stopped with a jerk.
    Immediately windows were flung open and heads appeared all along. A covey of officials descended onto the line and began peering beneath the coach. They were soon joined by the driver in his long blue coat. An excited conclave took place. The trouble appeared to be caused by the brakes of the Roumanian coach and the driver began plucking at a lever which projected from one of the bogeys. The officials followed suit and each in turn pulled the offending lever, to a running fire of facetious comment from the carriage windows.
    Several passengers now took it into their heads to scramble down on to the line and gather round the group of officials. They were quickly followed by others. One or two waggled the lever with an air of understanding.
    Carruthers, from his vantage-point at the window, watched the scene with amusement. Suddenly he heard the compartment door behind him open. “Pardon, Monsieur, will you please tell me what is the matter?” said a clear voice in English.
    As he turned to reply, Carruthers gave no indication of his delight at this good fortune.
    “Apparently,” he said gravely, “an overheating brake. As you see”—he waved his hand towards the commotion below—“the matter is now receiving attention.”
    A faint smile hovered on her lips. Her beauty was more than ever apparent.
    “May I ask, Madame,” pursued Carruthers, “how you knew that I was English.”
    The smile deepened.
    “If this had been England,” she answered, “the passengers would have waited patiently in their compartments for the train to start again. It would occur to no one to leave the train. Over here we order things differently.”
    Carruthers laughed.
    “Madame is a psychologist,” he said with a slight bow.
    She did not respond but looked anxiously at the gesticulating assembly on the line.
    “Tell me, Monsieur,” she asked seriously, “do you think that we shall be delayed for long?”
    “I think