The man who got down was the fellow who had gone through the car looking for the girl.

The locomotive pump throbbed noisily and Lister could not hear their talk, but he thought they argued.
The one who came up the line looked impatient and put his hand on his companion's arm, as if to urge him away.

The other stepped back, and his gesture implied that he refused to go.

The train was long, the passengers were asleep, and the men, no doubt, imagined nobody saw them.
Lister thought the fellow who got down did not know the girl was gone and did not mean to leave the train without her.

The light touched the men's faces, and it was obvious that one was angry and the other disturbed.