When new jobs or vacan­cies occur, the old­est in ser­vice qual­i­fied employ­ee shall be con­sid­ered for said posi­tion, qual­i­fi­ca­tions shall be con­sid­ered by the Depart­ment and the­Union.  If the old­est employ­ee in senior­i­ty can­not hold down said posi­tion, he shall be returned to his for­mer posi­tion; with­in the bar­gain­ing unit.  In the event of a reduc­tion in force, the last man hired shall be the first man laid off.