1、问题的提出内蒙古炼油厂铁路专用线由距呼和约17km的白塔站分出,至厂区添必梁站全长约28km,根据运量及运输单位的设置情况,约需60台电话,其中5台在添必梁站。在这种情况下,采用音频选号电话或集线器,因其容量不能满足要求,所以此方案是不可行的。如果由呼和 1, the problem raised Inner Mongolia refinery railway lines from the Hohhot about 17km away from the White Pagoda station to Tim Tsuen plant site full length of about 28km, according to traffic and transport units set up about 60 calls, Five of them are at Tim Bridges. In this case, the use of audio numbering telephone or hub, because of its capacity can not meet the requirements, so this program is not feasible. If by the call