Rail transportation is actually classified as follows: trunk rail transportation (high-speed passenger transportation, _________________), urban rail transit (subway, light rail, suburban railway and monorail) and new type rail transportation (maglev and vacuum high-speed rail train). 轨道交通实际分为:干线轨道交通(高速客运，_________________)、城市轨道交通(地铁、轻轨、城郊铁路、单轨)和新型轨道交通(磁悬浮、真空高速铁路)。
A、heavy-loaded freight transportation 重载货物运输
B、intercity railway 城际铁路
C、highway transportation公路运输