What is "straphangers"

Usage examples of "straphangers".

Then, as the train entered a straight-away, the interior lights would come on again and she would become aware once again of the acrid smell, the jostling of nearby straphangers, the miniature television surveillance cameras (locked in protective cages and subsequently spray-painted blind), the stylized multicolored map showing the complete underground transportation system of the City of New York, and the high-frequency screech of the brakes as they pulled into the stations.

What a glorious end-of-day tonic for clock watchers, straphangers, and freeway slaves.