城市轨道交通专业英语课程教案（第6周3—4节）授课题目
Unit 2 Knowledge of Traffic
Lesson 5 Rail Transit （下）
授课类型
讲授型
教学目标Master the related knowledge of Rail Transit
重点2.Heavy Rail Transit （下）
muter Railroads
主要教学内容2.Heavy Rail Transit 重轨运输（下）
Therefore , it is generally feasible only in outlying areas where land or in freeway medians where the cost of land and grade separations can be shared with highway project.因此这种形式通常只在地价便宜的外围地区才是可行的，或在高速公路的中央分隔带上修建，因为这时土地和立交的成本可以分摊于公路工程项目。

Elevated construction costs are perhaps twice as much as for facilities at grade, but the land below can be used for a street, for parking or industrial uses, or even for linear parks; 高架结构的造价大约是地面工程的两倍，但高架结构的下部空间可以用作街道、停车或工业用地甚至可以作为带状公园。

HART in Albany and El Cerrito, CA, is an example of the latter.旧金山海湾地区的快速运输系统使是后者的一个例子。

In densely built up areas ,including CBDs, the adverse impacts of noise and reduction of daylight militate against elevated construction.在建筑密度大的地区，包括中心商业区在内，噪声以及日照减少的不利因素会对高架结构产生不利影响。

A doubling, or even tripling, of costs occurs if underground alignments are considered.如果考虑用地下方案，造价将会是两倍或三倍。

However, land costs are minimized by the use of street rights-of-way easements under private property instead of outright purchase, and development of air rights over those parcels which must be acquired.但是，由于采用街道通行权、不直接购买上地而是利用私人上地的通行权以及开发那蚱必须获得的小地区的领空权等办法，土地造价会降到最低。

Environmental deterioration is minimized, although it must be recognized that underground travel is as attractive to passengers as moving in daylight.虽然必须承认地下乘车出行对乘客来说并不像地上乘车出行那样具有吸引力，但地下乘车出行将会使环境的恶化程度降低。

Art determines the need for crossovers and storage tracks.运营分析将决定是否有必要修建天桥和备用轨道。

The former are needed primarily for track
maintenance purposes, while the latter provide for turning trains back short the end of the line, or for storing disabled vehicles.其中前者主要是供检修轨道使用，后者则供车辆在路线終点倒车或停放不能行驶的车辆用.
muter Railroads 市郊运输
In some large metropolitan arras, such as New York, London,Paris, and Tokyo. a large burden of urban transportation is borne by intercity railroads.在一蚱国际大都市，如纽约、伦敦、巴黎和东京，城市交通的大部分是由城市间的轨道运输来承担的。

Many of the lines involved were located for intercity travel and , in generating urban land uses along their corridors, found themselves serving increasing numbers of local trips. 许多为城市间通行而设置的轨道路线，在其沿线的土地上兴起了新的城市，致使利用轨道运输去当地旅行的数量也日益增加。

Up to about 1920 some railroads added in the suburbs where they found sufficient demand. 到大约四20年为止，山于大量的交通需求，市郊的一铁路线路持续增加。

However, since that time many railroads have been abandoned because Of the high costs d railroad operation and reluctance by management to allow long-distance passengers and freight customers to subsidize urban transportation. 然而，从那时开始，由于铁路运营费用过高以及不愿通过管理手段向长途乘客和货主征收城市交通补贴，许多线路已经被废弃。

Originally ,railroads were usually laid out at grade with level highway crossings.起初，铁路通常铺设在地
面上，与公路平面交叉。

In some cities,such crossing were eliminated later by changing grade of the railroad, therefore providing it with a fully exclusive right-of-way .后来，通过调整轨道的坡度，这种形式的交叉在一些城市被取消。

因此，轨道运输就具有了专用通行权。

Passenger operation was, however, still sharing this facility With freight movements.但是，客运仍然与货运共同使用此种运输设施
A major problem of urban railroad services is the
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