action ferroviaire

CONT: Ce dernier indice [titre de sociétés de chemins de fer] en fait était autrefois connu sous le nom de l'indice Dow Jones des chemins de fer et était une moyenne des cours des principaux titres de sociétés de chemins de fer américaines.

CONT: The latter [rail stock], by the way, was called the rail average in Dow's day and actually consisted of an average of the leading U.S. rail stocks.
OBS: The correct French equivalent is ""action"" in this context because ""stock"" and ""share"" are used interchangeably as a singular noun. However, ""stock"" is usually a collective noun, with ""actions"" as its French equivalent and ""shares"" as its synonym.