Ninu iṣowo ipolowo ode oni, awọn ami ifihan ipolowo ati awọn fireemu ipolowo ni a lo nigbagbogbo, ati pe irin naa jẹ ohun elo deede, gẹgẹbi awọn ami irin, awọn iwe ipolowo irin, awọn apoti ina irin, ati bẹbẹ lọ Awọn ami irin kii ṣe fun ipolowo ita nikan, ṣugbọn tun ...