Worried transit officials asked lawmakers to imagine a CTA train packed with inebriated, possibly irate fans after a Cubs night game, then consider the wisdom of adding gun-toting passengers to the potentially volatile mix. Or what if a thief grabbed a bus rider's iPhone — a not-uncommon crime — and an armed commuter tried to stop the criminal? Those scenarios were raised Friday by Chicago transit officials, who called on state legislators to prohibit anyone from carrying a weapon on buses and trains if a concealed-carry law is adopted in Illinois. Transit agencies across the state contend that allowing individuals...