... class of traffic 运输等级（快、慢） class of trains列车等级（速度） class of triangulation 三角测量等级 ...
双语例句
1
The tourist quota applies to perhaps 200 trains a day out of a total of 9, 000 trains, and the quota might be just 2 and seldom more than 12 places, spread over each class.
The trains are also packed with locals following the decision in the middle of 2008 by Thailand's rail network to offer free third-class travel for Thai nationals on certain routes.
根据泰国铁路网在2008年中旬的决定，列车同时也为当地人提供某些路线的三等车厢搭载服务。
3
AC Chair class is found on a number of 'intercity' daytime trains (for example Delhi-Jaipur, Delhi-Agra, Delhi-Kalka for Simla), and is available to holders of a AC2 class IndRail pass.