一、总论三开道岔又称复式道岔,分为复式异侧对称道岔、复式异侧不对称道岔,复式同侧不对称道岔等。它是一种特殊形式的道岔,见图1。每组道岔有四根尖轨,三组辙叉,以保证由一线向三个方向的分歧,来代替二付普通的单开道岔。在复杂的道岔群中,以及特殊的地点上,可以起到缩减道岔长度及解决单开道岔布置不下去的困难。 First, the general Three turnouts turnout, also known as double turnout, is divided into compound heterophasic turnout, duplex asymmetric turnout, duplex ipsilateral asymmetric turnout. It is a special form of turnout, see Figure 1. Each set of switches has four sharp rails, three frogs, in order to ensure the divergence from the first line to the three directions, instead of two to pay the ordinary single turnout. In complex turnout groups, as well as special locations, can reduce the length of the turnout and solve the difficulties of single-turnout can not be arranged.