电缆规格说明-中英对照-译路通武汉翻译公司
27.5 电缆套管终端
在标书中明确规定，为非金属/抗腐蚀性类型，由加强型纤维塑料制成。在电缆套管终端不允许采用焊接或者干接合。导线的终端必须采用经销商的连接终端进行套装。全部轨道电路接线必须在轨道的电缆套管终端使用跨接线，在连接轨道前进行封装。不得在地下有任何电缆接头。全部电缆接头应该在电缆分线盒中进行封装，做好标记录并设置隔离装置。
每个电缆接头至少有10米的电缆必须埋设在分线盒下面，用沙盖住并且以砖进行保护。
E. 27.6电缆寿命和规格
全部电缆和电线的等级和质量：在热带状况下的正常使用寿命不少于20年。
E. 27.7电缆平面图
提交一张显示单个电缆、终端点、备用导线和电缆规格参考的布置图。
E. 27.8电缆的铺设
电缆铺设的最小深度为地表下1米，并在电缆的上下覆盖不少于100毫米厚的沙层。在沙层覆盖的上方，铺设一级品的砖块或板坯，防止对电缆造成损坏。在电缆穿过轨道的地方提供GI管。凡是电缆横越桥梁或者通过水平交叉口时，使用管材对其进行保护。沙料、砖块、板坯、管材和桥梁固定装置由供应商负责提供。
电缆交叉处通过铁路、拦路木和站台必须采用钻孔方式进行，除非：
电缆穿过的轨道必须保证：
(i) 电缆以正确的角度穿过轨道
(ii) 电缆的穿过轨道的路线不允许安排有接点和交叉处。
另外承包商必须保证：
(i)管沟的挖掘的长度不应过长，并且：
(ii)挖掘作业不得整夜暴露在外；管沟的挖掘、电缆的铺设和填埋不得在同一天进行。
沟渠的回填必须采用正确的方式；土壤必须按时夯击并加固。
在站场存在有信号电缆、电信电缆和电力电缆。承包商必须特别留意，在沟渠土壤的挖掘期间，不得对这些电缆造成损坏。
每个电缆的金属保护必须连接有专门的地接点。
地下电缆管道必须通过电缆标识员的鉴定，由混凝土或者其它批准材料制成。
E. 27.9 接线和终端
全部电路必须尽可能简单，并且根据最优的铁路信号原则和惯例进行设计。电路图必须清晰，并清楚准确地显示每根电线的连接点。同一终端不得连接两根以上的电缆。电路图和符号必须采用认可的标准；电路说明采用英语；尺寸为米和厘米。
任何外用仪器的操作电源必须配有合适保险丝。
E. 28. 信号器安装的地接
总则E. 28.1
浪涌电压的产生
由于与外用电路连接，机电、电力和电子信号设备在暴风雨的天气期间，暴露于极大的浪涌电压下。浪涌电压的引起是由于：
■ 直接的遭雷击；
■ 由于暴风雨的影响对传输线造成带电；或频繁地，
■ 在某些距离遭遇雷击 (间接遭遇雷击)
E. 28.2损坏机制
间接遭遇雷击产生的浪涌电压，几乎可以使所有设备的信号发生故障。
浪涌电压是由于户外电路和地接之间显著的电位差造成的，地接可视为零电位。由于下列电压差可导致损坏的发生：
■ 设备输入端和输出端；和
■ 内部电路和外包装。
重要的是必须注意，间接雷击的影响不总是具有破坏性，它们所强加的应力是设备的使用年限降低的因素之一；使用寿命的降低是绝缘损耗、组件特性的恶化、以及开关触点的损耗等原因造成的；
E. 28.3保护总则
对于损坏机制，信号设备的保护可以通过：
● 增加设备的非导电性，
● 在发生雷击的时候，保证全部设备与接地具有相同的电势；并且
● 对受影响的导线采取某些预防措施。
目标是防止因雷击在设备里不同的点之间引起较大的电位差，从而产生的电压浪涌。并可能对装置造成损坏。当遭遇到雷击的时候，确保全部设备与接地具有相同的电势；在电压浪涌存在期间，通过将设备的全部终端套管，以及相临的金属结构连结到同一点进行保护。
实际上，这些是通过冲击制动装置与一个较大横截面铜导体，称为一个“等势总线”接地点连接的。
E. 28.4接地要求
所有信号系统部分的安装必须提供地接，保护人员和设备的安全；不过由电池提供电力的内部和外部电气电路必须与地接隔离；提供的地接保护包括：
■ 与地接的连接装置电阻低；
■ “等势总线”与地接连接；并且
■ 从设备到总线的地接连接线采用合适的连接方式。
E. 28.5信号和电信设备的接地必须分开
使用两种类型的地接点：
(a) 管状地接点：安装包括：
■ 一条长度为3.50米电镀钢管；以及
■ 单股或双股接线，采用镀镉黄铜或者铜铝合金的半圆形方式，通过装有夹板的螺栓和电缆连结。
这种方法允许采用多种结合方式。如果有必要降低一个地接点的电阻，可采用多根管材进行并接。 原则上，每个地接点不允许超过4根管材；通常情况下，并接的管材应该至少相隔2.50米以上。
(b) 埋设在新建大楼地基里的地接点(这个项目的价格在D段落有说明：车站和大楼建筑)：
在新建车站/设备大楼的施工期间，这类地接点包括一个埋设在地基洞穴里的环形导体。环形导体围绕在大楼的周边，并且以下列两者中任何一种类型进行施工：
(i). 一个最小横截面为25 mm2铜带或者铅包导体；或者
(ii). 一个至少2毫米厚，横截面至少为25 mm2的铜带；或者
(iii). 一条3毫米厚，横截面至少为100 mm2的钢带，埋设在边缘地带；或者
(iv). 一条横截面至少为95 mm2的钢索。
铜导体的安装必须保证和地接接触良好。
钢导体(钢带或电缆不一定要求进行电镀)铺设在混凝土地基里，必须有一层至少3厘米厚的混凝土。
新建信号大楼配备有埋设在地基下面地接装置。大楼埋设的地接采用管状地接点，用于提高地接的质量。
如有可能，将接地点的位置设在没有地下实用装置的地区：例如铠装电缆、水和煤气管道、下水道、大楼基础、或者对乘客开放的地区。
E. 28.6地接的连接
安装的地接和相邻的信号设备必须与“总地接点”连接；连接装置的电阻必须非常低，并且能使“总地接点”和地接之间的电势差减到最小。
使用在连接装置上导体的选择，必须根据连结的设备而定。承包商有责任对系统进行设计：系统产生的阻抗必须足够低；常用的信号器导体的类型如下：
■ 施工现场配电箱：一个最小横截面为25 mm2绝缘铜导体；或者
■ 施工现场配电柜和工棚：最小横截面为25mm2的两根绝缘的铜导体与地接网络的不同点连接。
E. 28.7 等势总线
等势总线的作用：必须保证设备的全部零件都处于相同的电势，无论是采用直接或者通过冲击制动装置的中转，防止在输入和输出之间，以及内部电路和安装的套管之间产生飞弧。
总线通过一条低阻抗的电路，将放电电流的主要部分转入地接，防止在设备、导线和电缆间进行循环。在总线里不得有明显的电压降。重要的是拥有较大的铜横截面以及相对较短的连接长度，更进一步使电压降减少到最小；从总线到地接的连接线必须尽可能短，因此总线必须接近于地面进行安装。
接地电阻尽可能低；对电脑化或者电信设备来说，极限电阻不应该高于1欧姆。
等势接地装置的变通方法是在大楼里面安装一个环路，包括一个最小横截面为40 mm2的绝缘导线。该环路必须与地接点连接。
E. 28.8设备连接
全部设备和结构必须直接连接到称为“总地接点”的公用地接点上，可以是一根总线或者一根主要保护导线(这根导线的全度不允许断开)。
为防止造成地接电路的中断的相关问题，允许进行串行连接。
E. 28.9导线
室内连接使用一根横截面至少为2.5mm2的绝缘导线。户外和其它类似的连接使用一根横截面至少为10 mm2的绝缘导线。
E. 28.10 设备地接
信号系统必须与总线连接防止发生浪涌电压。通常情况下，连接装置为下列型号设备：
a) 机柜、支架和金属框架的地接终端，
b) 电缆铠装；
c) 电源侧的保护装置；
d) 电源电池测的保护装置；
e) 机电设备和电子设备之间保护连接装置。
为下列专业设备，提供符合上述规格的地接装置：
a) 继电器室：
i). 设备机架、机柜 (包括固定设备或者类似机柜) 和电缆；
ii). 通过低电压公用主体部分供电的设备，无论是直接与中性点或者通过插入不同断路开关接地，将机械接地点和地接连接起来，通过地接的连接装置连接到一起。
b) 电缆走线架：
i). 全部走线架和电源电缆铠装，
ii). 信号电缆 (以及电信) 铠装。
c)车站主控制室：
i). 控制和指示桌面，
ii). 任何辅助设备的支架外壳。
蓄电池室内的电池电源和信号器必须与地接连接。
E. 28.11导线防护物：
各个设备的接地连接说明，必须描述各种不同的接线注意事项，进一步防止任何剩余的浪涌电压，主要包括：
a). 将机电设备的电源电路从电子设备中分开；
b). 从其它导线和电缆分开可能存在潜在高电流的导体，如果发生雷击，防止在这些电路之间的发生相互干扰；
c). 将过滤器 (一般是内置电容器) 插入与电子设备的电源连接装置 (如果设备没有这样的电容器，将安装有一台保护装置) ；以及
d). 在相同的灯泡里，使用多电极的冲击制动装置，这样可以同时触发。
E. 28.12 冲击制动装置连接
在电压浪涌的情况下，实施下列注意事项，使设备的终端的剩余电压，进一步减小到最小，并完全排除危险：
i.冲击制动装置与使用接地电极的等势总线连接；
ii.服务于被保护的设备的电缆将直接与冲击制动装置连接；
E. 28.13接地漏电指示器
每个车站必须对电缆、电线和其它接地故障系统的监控设备配有至少两个接地漏电指示器。 接地渗漏的任何监测可以通过视觉在控制面板/ VDU 表明。
E. 29. 环境
施工场所的气候温暖并极其潮湿，非常容易发生腐蚀。年平均降雨量超过2500毫米，100毫米日均雨量是十分少见。最大的温度变化为7ºC到45ºC。在热带风暴和季风期间，可能发生气旋波，150千米/小时平均风速很常见。湿长时间度保持在90-100%范围内，并伴有极端高温天气。承包商必须考虑露天高温和高湿度，特别是密封箱子暴露在强阳光下的情况。 另外承包商必须考虑这一年内的较大降雨时期。
在夏天季节偶尔会发生较大的沙尘暴。全部户外设备在极端灰尘的环境里，不会发生任何性能下降的情况。
承包商必须保证全部材料的设计、施工和设备安装，包括控制面板/VDU，适合当地气候和天气。承包商有责任完全熟知本地气候状况对系统造成的影响。
依据EN60529条款，承包商必须为全部系统部件选择足够的保护设备，从而适合孟加拉国的环境条件。投标商必须提交与这些要求相符的建议。
另外，承包商必须保证，全部材料和设备都符合要求并且功能完好，并且能够在没有空调的情况下运行。设备的电力和机械特性承受至少+70°C的温度。推荐的电子和电脑化设备能承受上述气候状况。
E. 30. 图纸和手册
图纸所使用的符号必须与在孟加拉国内使用的“铁路符合”尽可能一致。如果需要使用特别的符号，必须给相应资料增加合适的图例。
承包商必须在本材料指定的时间内，或者在工程师直接指定的时间内，将包括本文件没有具体说明图纸、系统设计、锁定、控制器以及电路图或者其它任何工程师合理要求的文件提交给工程师通过。如果工程师不同意任何上述的资料或者提出的修改意见，承包商将再次提交给工程师，承包商收到的不同意和修改提议必须采用书面形式。
承包商必须在本材料指定的时间内，或者在工程师直接指定的时间内，提供安装手册、现场测试的说明书、货物和其部件的操作和维护手册。文件必须提供足够的细节方便业主安装、测试、操作、维护、拆除和重建作业，并且调整这批货物的全部部件。
工程师对上述文件的同意或收据，并不减轻承包商对其设计、图纸、说明书和手册的正确性的责任，并要求完全符合本文件中货物和相关服务的规定。无论工程师是否同意，承包商必须对负责任何变更本合同的施工作业或者，任何因与设计、图纸以及其它的细节发生的不一致、错误或者省略造成的延迟交付和安装作业，并对业主予以赔偿。
在施工作业完成之后,承包商必须进行安排，并提交详细的完工电路图：包括流程图、控制图表、保险丝分析、标记端子排、导线图表、完成架终止计划、电缆管道计划、位置箱子计划、轨道电路计划,等等。提交的文件按照工程师要求的1 + 4复印件提交，包括高分子原样。
E. 31. 资料和图纸的批准
E. 31.1当承包商按照其信号系统的设计进行施工时，必须提交包括的每种要素的电力和机械特性的细节说明，并获得工程师的通过。图纸的符号必须尽可能保持一致，并符合孟加拉国使用的“铁路符号”。在使用特别符号的情况下，必须在相应的文件中添加合适的图例。
E. 31.2根据详细的时间表，承包商提供的文件包括2个复印件、计算和图纸，在合同建规定的时间内提交工程师获得通过。
E. 31.3工程师必须在45日内，以书面形式批准承包商提交的任何图纸、电路图、或连锁表格。如果没有获得通过，工程师必须在规定的时间内，提供详细、正当的理由。承包商必须以合理的数目继续提交图纸；因此工程师有可能在规定的期限内，同意相同的提议。如果这些图纸在45(45)天内没被批准，或者没有充分原因，在相同的时期内以书面形式给出拒绝的提议，图纸视为被批准。
E. 31.4工程师返还的每张图纸的复印件必须标出“批准”或“返还再修改”字样。
E. 31.5任何在图纸的通过之前进行的作业由承包商自己负责。工程师有权对提交的请求附加任何细节，并且要求承包商在业主没有额外成本而相符设计规定的情况下做出任何变更。
E. 31.6承包商对由于不符合条款要求，造成执行过程中的任何延迟负责。
E. 31.7承包商提交的，工程师批准的图纸和其它资料，并不完全构成技术有效性，但表明施工的一般的方法和描述是令人满意的。工程师的批准不免除承包商在本合同中规定的任何责任。
E. 31.8在合同签署的60天内，承包商必须提交业主和工程师一份提交图纸和资料的详细名单和时间表。
E. 32. 安装
承包商必须为上述施工作业提供并且安装全部设备和材料，并符合“交钥匙”工程的要求。承包商负责提供技术合格的工程师、相关的技师和训练的人员，承担、监督、并在指定的时间内完成施工作业。工程师必须方便联系，为承包商站点工程提供参考意见，并为承包商站点的施工作业提供放样协助。
车站可提供现行信号、连锁、组块施工作业安排，必须为火车服务的单线作业的安全要求考虑。当场地的修改变更为双线作业时，信号安全和组块控制系统将不起作用。在车站上方的火车运行必须采用手工方法进行管理。车站两边的组块操作也恢复到手工方式。这样的手工操作，除引起火车的延迟之外将导致显著的安全危险。因此，这个时期应该将危险和作业计划减到最小，并在场地作业完成后，为双线作业引用新的信号系统。新系统将进行测试并且在一月内进行操作，根据场地的改造作业，操作开始的日期为车站信号开始运行的日期。
E. 33.任务和转包
E. 33.1. 除非合同另有规定，承包商不得任命或者将合同或者合同的任何部分或其利益，在没有事先获得业主批准的情况下，分配或者转交给他人。
E. 33.2除非合同另有规定，未经业主的书面同意，承包商不得将合同或者合同的任何部分转包给他人。
E. 33.3. 承包商必须以书面方式，将合同转包方的全部细则提交给当事人，并提供同意转包的性质和范围的全部细节。如果文件已经提交，并不减少承包商在合同下的任何责任或者义务。并且承包商对分承包人的行为、失误和疏忽负完全责任。
E. 33.4. 如果合同的任何部分，在没有事先经过业主同意的情况下，经承包商转包，将视为合同违约，承包商按照有关的条款承担责任。
E. 33.5在铁路施工工程中，雇用任何本地人，必须以书面形式事先获得业主同意。
E. 34. 组块操作的工作系统
车站之间有关组块操作的工作系统的单线和双线路作业，必须按照孟加拉国铁路一般规章和辅助规章的描述，执行传统“绝对分段制” (1981版)。
E. 35. 进度报告
从签署合同之日起，承包商每月发布并提供进度报告，进度报告包含执行作业的详细信息并附上一张最新的生产时间表的一份进度报告。
应工程师的要求，举行会议讨论工程进程。
工程师能接触信号器，证实工程进程并证实安装的设备符合合同描述。
E. 36. 测试、试运行和工程验收
E. 36.1 承包商根据在条款里的说明进行车间和现场试验。 承包商拟定一份详细的试验计划并提交给工程师通过。器械操作、必要人员安排以及试验证明书的发行，将由承包商负责相关开支。
在试验的开始之前至少45天内，承包商提交每个设计项目的测验参数的详细时间表给工程师获得通过。工程师必须在30天内在收到试验的时间表，将批准文书发给承包商。如果工程师没有在规定的时期，说明不同意的任何详细理由和原因。试验的时间表将视为经工程师批准，测试时间为上述时期的最后一天开始。
业主的系统试运行和验收之前，执行下列设备试验和安装：
E. 36.2 车间测试：
材料和设备的测试在施工期间并且在装运之前进行。业主和/或工程师有权随时参观施工现场的设备，承包商必须为这些参观提供方便。
在没有业主帮助的情况下，测试的执行并不免除承包商在随后的工程作业期间出现的缺陷所承担的责任。在工程师批准之前，工程师可以在工厂执行认为必要的全部试验。
E. 36.3一般试验：
运行测试所需要的全部仪器、电路和保护装置。
确定控制系统功能的运行试验。
测试确定的全部电路必须与合同批准的单个电路测试计划相符。
电动操作设备试验所确定的电力操作特性必须符合铁路的要求。
全部仪器测试的电压必须符合制造方的规格说明，以及灯具电压的额定电压。
E. 36.4 绝缘测试：
● 每个电路的绝缘电阻的试验，符合铁路制定的规范。
● 导体和电路全度之间的绝缘电阻不少于10欧姆，除非指定更高的绝缘电阻。
E. 36.5连锁试验：
● 任何部分轨道区域没有被轨道电路的信号控制时，轨道电路区域无任何信号，并且没有任何可以操作的的电路点。每个轨道电路部分都必须进行试验。
● 当一个信号清晰时，没有冲突的信号可能被清理。每个轨信号必须都进行试验。
● 测试确保火车后方的连锁得到解除，将轨道电路按照火车的通路的分接。每个轨电路都进行必须试验，确保轨道电路能根据每个电路图实施路线发布功能。
● 测试保证依靠这条电路，在火车通道自动取消路线的功能。
● 测试保证依靠这条电路，紧急事件的有效取消。
● 测试的铃铛和完整路线电路、模拟组、配电板、支架与灯具由承包商提供。
注：在连锁测试期间，承包商至少在现场安排二名监督人校正错误并且检查故障。
E. 36.6在上述项目或者任何其它认为必要的项目的试验开始之前，承包商必须在30天内，在试验开始之前，制定的每个测试项目的测验参数的详细时间表，证实安装的设备零件符合操作说明，并获得工程师通过。上述工程师的批准，必须在收到试验的时间表之后的20内提交给承包商。如果工程师不发布批准或者在规定的期限内，不详细说明不批准的正当理由，视为自上述时期的最后一天起工程师接受试验的时间表。
E. 36.7系统验收：
在系统或者其部件准备好验收至少15天之前，承包商必须以书面形式通知工程师。在上述通知日期30天内，工程师和承包商将一起参与并且完成验收试验。如果工程师没有参加试验，承包商将有权进行并且完成试验，并且即刻将测验结果寄给工程师。在试验完成的15天内，或者承包商在工程师不在场的情况下，工程师必须在15天内，将是否通过的测验的书面通知提交给承包商。在表示整个信号器的临时验收合格之前，工程师可能进行他可能认为必要的完整的信号系统的全部试验。
如果系统或者测试部件由于没有满足合同要求的规定，没有被业主接受，上述的书面通知必须指定声称的、存在或者发生缺陷处的细节。如果有要求，在测试过程中根据这项条款的规定，承包商必须以合理速度对相关或受影响的部件重复进行测试。验收不得以不影响系统使用的微小缺陷，拒绝验收，不过，这并不免除承包商对缺陷进行补救的义务。
E. 36.8信号器验收：
在整个信号器的试验已经完成并且宣布满意之后，必须将一份系统的临时的验收合格证交付给承包商。在任何情况下，在试验期间发现的全部不符合功能要求处已经被修理之后，整个系统的临时的验收合格证才能进行交付。
工程师已经发现的全部功能缺陷，必须在年末，在业主所出具一份最终验收合格证前，进行纠正。
双线运行信号系统的试运行(承包商的接受工作)只有在轨道、桥梁、车站大楼和有关的设备和新信号系统完成，经过测试，适于工程师对火车设施进行安全操作之后开始。
部分接管和部分双线运行的信号系统的操作，必须在连续3个车站(无论是从Tongi或者从Bhairab 市场开始，或者同时从两个车站开始)的作业已经完成，并且通过测试，适于工程师的火车设施进行安全操作之后开始。
E.27.5 Pot Ends
These are to be included in the Bid. These should be of the non-metallic/non-corrosive type and made from fibre reinforced plastic. No soldered or dry connections are permitted inside the pot ends. Conductors must be sleeved and terminated in distributors link terminals. All track circuit connections are to be terminated to track pot ends before these are extended to
the tracks by means of jumper wires. There should not be any cable joint under ground. All cable joints should be terminated in cable junction boxes with identification marks and isolating devices.
At each cable joint a minimum of 10 meters of spare cable shall be kept buried beneath the junction box and covered by sand and protected by bricks.
E.27.6 Cable Life and Specification
All cable and wire shall be of such grade and quality to serve a normal life of not less than 20 years under tropical conditions.
E.27.7 Cable Layout Plan
A layout plan shall be submitted showing location of individual cables, terminating points, spare conductors, and references cable specification.
E.27.8 Cable Laying
The minimum depth for installing cable shall be 1 meter below the surface and there shall be provided at least 100 mm sand below the cable and 100 mm sand above the cable. 1st class bricks or slabs shall be laid above the sand covering the cable to avoid the cable being damaged. Good quality GI Pipes shall be provided where cable cross the track. Where the cables are to run across bridges or through level crossings, they shall be protected by pipes. Sand, bricks, slabs, pipes and bridge fixtures are to be supplied by the Supplier.
Crossing of cable across railway track, level crossing gates and platforms shall be done by boring only.
When a cable has to cross the track, it shall be ensured that: (i) cable crosses the track at right angles and+ (ii) cable is not routed across the track under points and crossings.
Further the Contractor will ensure that:
(i) excavation of the trenches is not done in long lengths and
(ii) excavation does not remain uncovered overnight and trenches are dug, cables laid and refilling done on the sa,m<e day.
Back filling of the trenches shall be done properly and the earth shall be duly rammed and consolidated.
In station yard there are existing signalling, telecommunication and electric cables. Contractor shall take special care so that the cables are not damaged during excavation of earth for trenches.
The metallic protection of each cable shall be connected to a special common grounding point.
Underground cable routes shall be identified by cable markers made from concrete or other approved material.
E.27.9 Wiring and termination
All circuits shall be as simple as possible and designed in accordance with the best railway signalling principles and practices. Circuit drawings shall be clear and distinct and accurately show the connection points of each wire. Not more then two wires shall be connected to the same terminal. Circuit drawing and symbols shall be of a recognised standard and circuit description shall be in English and dimensions in meters and cm.
The cabin supply for any outside apparatus shall be provided with suitable fuses.
E.28. EARTHING OF SIGNALLING INSTALLATIONS
General Principles E.28.1 The Origins of Voltage Surges
Due to their connection to exterior circuits, electromechanical, electrical and electronic signalling
P
equipment is exposed to major voltage surges during stormy weather. Such voltage surges are caused by:
■ direct lightning strikes;
■ charging of transmission lines due to the effects of a storm; or more frequently,
■ by lightning strikes some distance away (indirect lightning strikes)
E.28.2 Destruction Mechanism
Voltage surges due to indirect lightning strikes are responsible for almost all signalling equipment failures.
A voltage surge results in the application of a significant potential difference between the outdoor circuits and the earth, which may be considered at zero potential. Damage occurs due to the voltage difference between:
■ the equipment input and output; and
■ the internal circuits and the casing in which they are housed.
It is important to note that while the effects of indirect lighting strikes are not always destructive, they are a factor in reducing the service life of equipment, by virtue of the stresses they impose. The mechanisms of reduced life are insulation breakdown, deterioration of component characteristics, and deterioration of switch contacts, etc.
E.28.3 General Principles of Protection
In view of the mechanism of destruction, signalling equipment is protected by:
• increasing the dielectric strength of the equipment,
• ensuring that all equipment is at the same potential as the earth when the lighting strike occurs; and
• implementing certain precautions in the effecting wiring.
The objective is to prevent the voltage surges caused by lightning strikes from creating large potential differences between different points in the equipment, which are likely to damage it. Ensuring that all equipment is at the same potential as the earth, when the lightning strike occurs is achieved by connecting all terminals of the protected equipment, its casing and adjacent metal structures, to the same point, during the time that the voltage surge is present.
In practice these connections are provided by surge arrestors connected to a large cross-section copper conductor referred to as an "equi-potential bus bar" which is then connected to an earthing point.
E.28.4 Earthing Requirements
All installations provided as part of the signalling system shall be earthed for reasons of personnel safety and equipment protection. However, the inside and outside signalling electrical circuits fed by the batteries are insulated from the Earth. The earthing protection provided shall comprise:
■ a low resistance connection to earth;
■ an “equi-potential busbar” connected to the earthing; and
■ suitable connections from the equipment to the busbar connection to Earth E.28.5 Earth for signalling and telecommunication equipment shall be separated.
Two types of earthing point shall be used:
(a) Tubular earthing points: The installation shall comprise:
■ a galvanised steel tube 3.50 m long; and
■ a single or double connector in the form of two cadmium-plated brass or copper-aluminium alloy half-rings, connected together by bolts and equipped with a cable clamping plate.
This method allows a variety of combinations. If it is necessary to reduce the resistance of an earthing point, a number of tubes shall be connected in parallel. In principle, an earthing point should not comprise more than four tubes and, as a general rule, tubes connected in parallel should be at least 2.50 m apart.
(b) Earthing points buried in the foundations of new buildings (price of this item to be included under Subsection D: Stations and Buildings):
This type of earthing point shall comprise a looped conductor buried in the foundation excavations during construction of new station/equipment buildings. The looped conductor shall run around the perimeter of the building and shall be fabricated from either:
(i). a copper bar or lead-sheathed conductor with a minimum cross-section of 25 mm2; or
(ii). a copper strip at least 2 mm thick and at least 25 mm2 of cross-section; or
(iii). a steel tape at least 3 mm thick and 100 mm2 of cross-section and laid on edge; or
(iv). a steel cable at least 95 mm2 in cross-section.
Installation of the copper conductors must ensure that they are in good contact with the soil.
The steel conductors (neither the tape nor cable need be necessarily galvanized) shall be laid in the foundation concrete and shall have a coating of concrete at least 3 cm thick.
New signalling buildings shall be provided with buried earthing below the foundations. Tubular earthing points shall be connected to the building’s buried earthing for improved quality.
Wherever possible, earthing points shall be installed in sound ground in an area free of underground utilities such as armoured cables, water and gas pipes, drains, foundations of buildings, or areas open to passengers.
E.28.6 Connections to Earthing
The earthing installed shall be connected to a “general earthing point” adjacent to the signalling equipment. These connections shall offer a very low resistance and shall minimise the difference in potential between the “general earthing point” and earth.
The choice of conductors used to provide these connections shall depend upon the equipment being connected. It is the responsibility of the Contractor to design a system, which produces sufficiently low levels of impedance. The following examples are provided as an example of the type of conductors typically used for signalling installations:
■ one insulated copper conductor, with a minimum cross-section of 25 mm2,for site distribution boxes; or
■ two insulated copper conductors with a minimum cross-section of 25mm2 connected to different points in the earthing network, for site cabinets and sheds.
E.28.7 Equi-potential Busbar
The equi-potential busbar shall function to ensure that all parts of the equipment are at the same potential, either directly, or through the use of intermediary of surge arrestors, to prevent flashover between inputs and outputs and between internal circuits and the casings in which they are housed.
The busbar shall also shunt the major part of a discharge current to earth, through a low-impedance circuit, and prevent it from circulating in the equipment, wiring, and cables. There shall be no significant voltage drop in the busbar. It is important that it has a large copper cross-section and be relatively short connected. To further minimise voltage drops, the connection from the busbar to earth shall be as short as possible and the busbar shall therefore be installed close to ground level.
The earth resistance shall be as low as possible. For computerised or telecommunication equipment, the maximum resistance should not be greater than 1 ohm.
An alternative method for providing an equi-potential connection to earthed installations shall be to install a loop inside the building, comprising an insulated conductor with a minimum cross-section of 40 mm2. This loop shall be connected to the earthing point.
E.28.8 Equipment Connections
All equipment and structures to be earthed shall be directly connected to a common earthing point referred to as the "general earthing point" which may be a busbar or a main protective conductor (this conductor shall not be interrupted throughout its length).
To eliminate problems, which might arise from a break in the earthing circuit, serial connections shall not be permitted.
E.28.9 Conductors
Indoor connections shall always be made using insulated conductors with a cross-section of at least 2.5mm2. Outdoor and other similar connections shall always be made using insulated conductors with a cross-section of at least 10 mm2.
E.28.10 Equipment to be Earthed
The signalling system shall be connected to the busbar for providing protection against voltage surges. In general, connections shall be provided for the following types of equipment:
a) the earth terminals of equipment cabinets, racks and metallic frames,
b) cable armouring;
c) protective devices on the power supply side;
d) protective devices on the power supply battery side;
e) protective devices for connections between electromechanical and electronic equipment.
Earthing in accordance with these specifications shall be provided, at a minimum, for the following specific equipment:
a) Relay Room:
i). equipment racks, cabinets (including solid state equipment or similar cabinets) and cable,
ii). equipment fed from low-voltage public mains, either directly with their neutral earthed or through an inserted differential circuit breaker, shall have their mechanical earthing points connected to earth and thus be connected together by the earth connection.
b) Cable Termination Racks:
i). all racks and power cable armour,
ii). the armour of signalling (and telecommunications) cables.
c) Station Master’s Room:
i). the control and indication desk,
ii). racks housing any ancillary equipment.
Batteries in the accumulator room supplying power to the signalling installations shall not be connected to earth.
E.28.11 Wiring protection:
The measures described for equipment connections to earth shall be complemented by the use of various wiring precautions to further protect against any residual voltage surges which may remain. These shall consist primarily of:
a). separating the power supply circuits for the electromechanical equipment from those for the electronic equipment;
b). separating conductors which may potentially carry high currents, in the event of a lightning strike, from other wiring and cables, to prevent interference by mutual interaction between these circuits;
c). inserting filters (generally built-in capacitors) into the power supply connections to the electronic equipment (equipment without such capacitors shall be equipped with a
protective device); and
d). using surge arrestors with multiple electrodes in the same bulb, such that they are tripped simultaneously.
E.28.12 Connection of Surge Arrestors
The following precautions shall be implemented to further minimise, and render non-hazardous, the residual voltage at the terminals of the equipment, on the occurrence of a voltage surge:
i. surge arrestors shall be attached to the equi-potential busbar using the earthing electrode;
ii. the cables serving the equipment to be protected shall be connected directly to the surge arrestors.
E.28.13 Earth Leakage Detector
Each station shall be provided with at least two earth leakage detectors for monitoring earth faults from cables, wires, and other system equipment. Any detection of earth leakage shall be indicated visually and audibly at the control panel/VDU.
E.29. ENVIRONMENT
The climate at the site of the Work is warm and extremely humid. It is very conducive to corrosion. Average annual rainfall exceeds 2500 mm. Daily rainfall of up to 100 mm is not unusual. The maximum temperature variation is beween 7ºC and 45ºC. During tropical storms and monsoons, cyclonic winds may occur and wind speed of average 150 km/h is not uncommon. Humidity can remain in the range of 90-100% for long periods of time in combination with maximum temperatures. The Contractor is reminded that high temperatures and high humidity in open land, especially in sealed boxes exposed to strong sunshine will occur. Furthermore the Contractor is reminded that heavy rainfall in periods of the year takes place.
Occasionally heavy dust storms occur during the summer season. All outdoor equipments shall be able to function without any degradation in their performance in the extremely dusty environment.
The Contractor must ensure that the design and construction of all materials and equipment installed, including the control panel/VDU, are suitable to the local climate and weather. It is the responsibility of the Contractor to be thoroughly acquainted with the impact of the local climatic conditions on the systems proposed.
The Contractor shall select an adequate device protection level according to EN 60529 for all system components which meet the environmental conditions of Bangladesh. The Bidder shall submit his proposal conforming to these requirements.
Furthermore, the Contractor must guarantee that all materials and equipment shall fit and function properly and shall be designed to operate without air conditioning. The electrical and mechanical characteristics of the equipment shall withstand temperatures of at least +70°C. Electronic and computerized equipment proposed shall withstand the climatic conditions described above.
E.30. DRAWING AND MANUALS
The symbols used for drawing shall conform as far as possible to the “Railway Symbols” in use in Bangladesh. In case special symbols are used, appropriate legend shall be added to the corresponding documents.
The Contractor shall submit to the Engineer for approval, within the time specified in this document or by the time directed by the Engineer where not specified therein such drawings, system design, locking and controllers, circuit diagrams or any other design documents as may be called for therein or as the Engineer may reasonably require. In case the Engineer
does not approve any of the above mentioned documents or propose modifications, the Contractor shall submit again to the Engineer, on receipt by the Contractor of such disapproval and proposal in writing.
The Contractor shall furnish the Engineer by the time specified in this document or by the time directed by the Engineer where not specified therein, with installation manuals, instruction books for testing on the site, operating and maintenance manuals for the goods and part thereof, in sufficient details to enable the Employer to erect, test, operate, maintain, dismantle, reassemble and adjust all parts of the goods.
Approval or receipt of the above documents by the Engineer shall not relieve the Contractor of his responsibility for the correctness of his designs, drawings, instructions and manuals and for full compliance of the goods and related services with the provision in these documents. The Contractor shall be responsible for and shall pay to the Employer liquidated and ascertained damages caused by any alteration to the works under the Contract or any delay in the delivery and installation works of the goods due to any discrepancies, errors or omission in the designs, drawings and other particulars supplied by him, whether such designs, drawings and particulars have been approved by the Engineer or not.
After completion of the work, the Contractor shall arrange and submit detailed completion drawing consisting of circuit diagrams, flow chart, control chart, fuse analysis, tag block, wiring chart, complete rack termination plan, cable route plan, location box plan, track circuit plan, etc. as approved by Engineer in 1+ 4 copies including polyester sheet as original.
E.31. APPROVAL OF DOCUMENTS AND DRAWINGS
E.31.1 As the Contractor progresses with his design of the signalling system, he shall submit the details of the electrical and mechanical characteristics of each of the elements covered by the Specifications to the Engineer, for approval. The symbols used for drawings shall conform, as far as possible, to the "Railway Symbols" in use in Bangladesh. In the case where special symbols are used, an appropriate legend shall be added to the corresponding documents.
E.31.2 Two copies of the Contractor’s documfents, calculations and drawings shall be submitted to the Engineer for approval within the periods established by the Contract and/or according to the Detailed Time Schedule..
E.31.3 The Engineer shall approve any drawings, circuit diagrams, or interlocking tables, in writing, within forty five (45) days from the Contractor’s submittal of the same. In the case of non-approval, the Engineer shall provide detailed, justified, reasons thereof within the said period. The Contractor shall submit the drawings progressively, and in reasonable numbers, such that it is possible for the Engineer to approve the same within the stipulated period. If these drawings are not approved within the said forty five (45) days, or the valid reasons for non-approval are not given in writing within the same period, the drawings shall be deemed to have been approved.
E.31.4 A copy of each drawing shall be returned by the Engineer indicated as "approved" or "returned for corrections".
E.31.5 Any work carried out prior to the approval of drawings shall be at the Contractor's own risk. The Engineer shall have the right to request any additional details and to require the Contractor to make any changes in the design which are necessary to conform to the provisions without additional cost to the Employer.
E.31.6 The Contractor shall be responsible for any delay in the performance of the works due to the non-fulfillment of any requirements of this clause.
E.31.7 The Engineer’s approval of the drawings, and other documents prepared by the Contractor, shall not constitute a full technical verification, but shall indicate only that the general method of construction and detailing is satisfactory. Approval by the Engineer will not exempt the Contractor from any responsibilities defined under this Contract.
E.31.8 Within 60 days of Contract signing, the Contractor shall submit to the Employer and the Engineer a detailed list and schedule of the drawings and documents that will be submitted.
E.32. INSTALLATION
The Contractor shall supply and install all equipment and materials for the above works at the Stations on "turn-key" basis. The Contractor shall be responsible for providing technically qualified engineers, technicians and trained staff to undertake, supervises, and complete the installations within the specified time limit. The Engineer will be available for liaison purposes, to provide a point of reference for the Contractor for site engineering decisions and to assist the Contractor in the setting out the site works.
The existing signalling, interlocking and block working arrangements available at the stations cater for the safety requirements of single line operation of train services. When yard modification will be carried out for conversion to double line layout, safety signalling and block control system will become inoperative. Train movement over the station shall have to be managed by manual methods. Block operation with stations on both sides shall also revert to manual methods. Such manual operation, in addition to causing delay to train movement will introduce significant safety risks. This period should, therefore, be minimized and work programme shall be so made as to introduce new signalling system for double line operation immediately after the yard works are completed. The new system shall be tested and made operational within one month from the date the station signalling becomes in operative due to yard remodeling works.
E.33. ASSIGNMENT AND SUB-LETTING
E.33.1 Except where otherwise provided by the Contract, the Contractor shall not assign or transfer the Contract or any part thereof or any benefit or interest therein or there under without the prior written consent of the Employer.
E.33.2 Except where otherwise provided by the Contract mlo ejContractor shall not sublet any part of the contract without prior written consent of the E^pTOyer.
E.33.3 The Contractor shall give, in writing to the full particulars of the party to whom he proposes to sub-let a portion of the Contract and shall give full details of the nature and extent or such consent, if given, shall not relieve the Contractor from any liability or obligation under the contract, and the Contractor shall be fully responsible for act, defaults and neglects of the sub Contractor. E^^
E.33.4 If any part of the Contract is sub-let by the Contractor without the prior consent of the Employer, this will be treated as breach of the Contract, and the Contractor will be liable to action under the related clause.
E.33.5 Prior written consent of Employer shall be taken to employ any local person for working in the project at railway premises.
E.34. WORKING SYSTEM FOR BLOCK OPERATION
The working system for the block operation between the stations concerned shall be based on the conventional "Absolute Block System" for single and double line working as applicable and as described in General Rules of Bangladesh Railway and Subsidiary Rules thereto (1981 edition).
E.35. PROGRESS REPORT
The Contractor shall issue and furnish every month, starting from the day after signing the Contract, a Progress Report that shall contain detailed information on the performed work during the preceding period and shall be accompanied by an updated manufacturing time schedule.
At the request of the Engineer, meetings shall be held to discuss the progress of works.
The Engineer shall have access to the signalling installations to verify the progress of works and to verify that the equipment installed meets the Contract Specifications
E.36. TESTING, COMMISSIONING AND ACCEPTANCE OF WORKS
E.36.1 The Contractor shall perform workshop and field tests in accordance with the provisions stated in the Specifications. The Contractor shall draw up a detailed test program and submit it to the Engineer for approval. The provision of instrumentation, the necessary personnel and the issuance of test certificates, will be at the Contractor's expense.
At least 45 (forty five) days before the commencement of tests, the Contractor shall submit to the Engineer, for approval, the detailed schedules of the test parameters for each of the designed items. The said approval of the Engineer shall be issued to the Contractor within 30 (thirty) days after receipt of the schedule of tests. Should the Engineer not issue the approval nor state any detailed, justified, reasons for non approval, with in the stipulated period, the schedule of tests shall be deemed to be approved by the Engineer, as of the last day of the said period.
The following tests of equipment and installations shall be carried out before commissioning and acceptance of the system by the Employer:
E.36.2 Workshop Test:
• Material and equipment will be tested during construction and before shipping. The Employer and/or Engineer will have the right to visit, at any time, the factory where the equipment is under construction. The Contractor shall facilitate these visits giving suitable assistance to this purpose.
• Execution of test without the Employer’s assistance will not relieve the Contractor from any responsibility due to defects that may subsequently arise during site test or service. The Engineer may carry out all the tests in factory he may deem necessary before giving his approval.
E.36.3 General Tests:
Service tests to determine that all apparatus, circuits and protective devices function as intended.
Service tests to determine that control system functions as intended.
Test to determine that all circuits conform to approve circuit plans by testing individually each contact selection.
Tests of all electrically operated devices to determine that electrical operation characteristics are in accordance with the Railway requirements.
Test to determine that voltage for all apparatus is in accordance with manufacture’s specifications and voltage applied to lamps is in accordance with rated voltage.
E.36.4 Insulation Tests:
• Tests of insulation resistance of each complete circuit, in accordance with the Railway practice shall be made.
• The insulation resistance shall not be less than 10 mega-ohms between the full circuit length of the conductor and ground, unless a higher insulation resistance is specified elsewhere.
E.36.5 Interlocking Tests:
• When any track section is occupied no signal controlled by that track circuit section should clear and no points in that track circuit zone should operate. This test shall be made for each track circuit section.
• When a signal clears, no conflicting signals can be cleared. This test shall be made for each signal.
• Test to ensure that interlocking is released as the rear of the train leaves the limit of interlocking, shunting track circuit in sequence, corresponding with the passage of the train. The test shall be made to each track circuit to ensure that the route release
functions as per circuit diagram.
• Test to ensure that automatic cancellation of routes on passage of the train, is in accordance with the circuit.
• Test to ensure that emergency cancellation of routes is effective and in accordance with the circuits.
• For the bell test and complete route testing of the circuits, a simulation panel, switchboard, rack with lamps shall be supplied by the Contractor.
Note:During interlocking tests, a minimum of two supervisors shall be provided at site by the Contractor to set right the faults and check the same.
E.36.6 Before the commencement of the tests of the above items or any other item considered necessary, the Contractor shall for approval of the Engineer at least 30 (thirty) days before commencement of such tests the detailed schedules of the test parameter of each of the items designed to prove that the installed parts of the equipment will operate in accordance with the specification. The said approval of the Engineer shall be issued to the Contractor within 20 (twenty) days after receipt of the schedule of tests. Should the Engineer not issue the approval or not state the detailed justified reasons for non approval within the stipulated period, the schedule of tests shall be deemed to be approved by the Engineer as of the last day of the said period.
E.36.7 System Acceptance:
The Contractor shall in writing notify the Engineer that the system or part thereof is ready for acceptance tests at least 15 (fifteen) days before commencement of such tests. Within 30 (thirty) days from the date of the said notice the Engineer and the Contractor shall jointly carry out and complete the acceptance tests. In case the Engineer does not attend at the tests the Contractor shall have the right to carry out and complete the tests and shall forthwith forward the test results to the Engineer. Within 15 (fifteen) days from completion of the acceptance tests, or in case the tests were completed by the Contractor in the absence on the Engineer, within 15 (fifteen) days from the receipt by the Engineer of the test results the Engineer shall give the Contractor a written notice whether the system or tested part thereof is accepted or not. The Engineer may carry out all the tests of the complete signalling system he may deem necessary before giving Provisional Acceptance Certificate for the whole signalling installations.
If the system or tested part thereof is not accepted by the Engineer due to the fact that the system or tested part thereof does not fulfill the requirements of the Contract, the above mentioned written notice shall specify the particulars of the defects alleged and of where the same are alleged to exist or to have occurred. The Contractor shall with all reasonable speed under the acceptance test procedure for the relevant or affected part shall, if required, be repeated in accordance with the conditions of this Clause. Acceptance shall not be refused because of minor deficiencies, which do not prevent the system or part thereof to be put into use. However, this will not relieve the Contractor of his obligations to remedy said deficiencies without delay.
E.36.8 Acceptance of the Signalling Installations:
After the tests of the whole signalling installations have been completed and declared satisfactory, a Provisional Acceptance Certificate of the system will be delivered to the Contractor. In all cases that Provisional Acceptance Certificate for the whole system will be delivered only after all disfunctioning detected during tests have been repaired.
A Final Acceptance Certificate will be issued by the Employer at the end of the 1 (one) year’s warranty period if during that time, all functional deficiencies which have been detected by the Engineer, have been rectified.
Commissioning of signalling system for double line operation (taking over of Contractor’s work) shall start only when the works of track, bridges, station buildings and related facilities and new signalling system have been completed and tested and found satisfactory for safe operation of train services by the Engineer.
Part taking over and part operation of signalling system for double line operation may be considered only when at least three consecutive stations (starting either from Tongi or from Bhairab Bazar or starting from both stations at a time) have been completed and tested and found satisfactory for safe operation of train services by the Engineer.
2012.10.23