He saluted her with a frown upon his face, but evidently with familiarity.

The change in the girl's demeanor was instantaneous.

Evidently she did not wish to offend the newcomer, nor did she wish to break with the motorman.
All were ill at ease, distraught, vexed, worried.

She tried to bring the newcomer into the conversation, which he refused.

The motorman eyed him with hostility now and again, as he dared to neglect his duty, but smiled uneasily in the face of the girl when she addressed him with an attempt at freedom.
Bye and bye the youth took the empty seat by the side of the girl, and endeavored to draw her into conversation to the exclusion of the motorman.