電纜規格說明-中英對照-譯路通武漢翻譯公司

27.5 電纜套管終端
 在標書中明確規定，為非金屬/抗腐蝕性類型，由加強型纖維塑料制成。在電纜套管終端不允許采用焊接或者干接合。導線的終端必須采用經銷商的連接終端進行套裝。全部軌道電路接線必須在軌道的電纜套管終端使用跨接線，在連接軌道前進行封裝。不得在地下有任何電纜接頭。全部電纜接頭應該在電纜分線盒中進行封裝，做好標記錄并設置隔離裝置。

每個電纜接頭至少有10米的電纜必須埋設在分線盒下面，用沙蓋住并且以磚進行保護。

E. 27.6電纜壽命和規格
全部電纜和電線的等級和質量：在熱帶狀況下的正常使用壽命不少于20年。

E. 27.7電纜平面圖
提交一張顯示單個電纜、終端點、備用導線和電纜規格參考的布置圖。

E. 27.8電纜的鋪設
電纜鋪設的最小深度為地表下1米，并在電纜的上下覆蓋不少于100毫米厚的沙層。在沙層覆蓋的上方，鋪設一級品的磚塊或板坯，防止對電纜造成損壞。在電纜穿過軌道的地方提供GI管。凡是電纜橫越橋梁或者通過水平交叉口時，使用管材對其進行保護。沙料、磚塊、板坯、管材和橋梁固定裝置由供應商負責提供。
電纜交叉處通過鐵路、攔路木和站臺必須采用鉆孔方式進行，除非：
電纜穿過的軌道必須保證：
(i) 電纜以正確的角度穿過軌道

(ii) 電纜的穿過軌道的路線不允許安排有接點和交叉處。
 
另外承包商必須保證：
(i)管溝的挖掘的長度不應過長，并且：

(ii)挖掘作業不得整夜暴露在外；管溝的挖掘、電纜的鋪設和填埋不得在同一天進行。
溝渠的回填必須采用正確的方式；土壤必須按時夯擊并加固。

 在站場存在有信號電纜、電信電纜和電力電纜。承包商必須特別留意，在溝渠土壤的挖掘期間，不得對這些電纜造成損壞。

每個電纜的金屬保護必須連接有專門的地接點。

地下電纜管道必須通過電纜標識員的鑒定，由混凝土或者其它批準材料制成。

E. 27.9 接線和終端
全部電路必須盡可能簡單，并且根據最優的鐵路信號原則和慣例進行設計。電路圖必須清晰，并清楚準確地顯示每根電線的連接點。同一終端不得連接兩根以上的電纜。電路圖和符號必須采用認可的標準；電路說明采用英語；尺寸為米和厘米。
任何外用儀器的操作電源必須配有合適保險絲。

E. 28. 信號器安裝的地接
總則E. 28.1   
浪涌電壓的產生

由于與外用電路連接，機電、電力和電子信號設備在暴風雨的天氣期間，暴露于極大的浪涌電壓下。浪涌電壓的引起是由于：
■ 直接的遭雷擊；
■ 由于暴風雨的影響對傳輸線造成帶電；或頻繁地，
■ 在某些距離遭遇雷擊 (間接遭遇雷擊)

E. 28.2損壞機制
間接遭遇雷擊產生的浪涌電壓，幾乎可以使所有設備的信號發生故障。
浪涌電壓是由于戶外電路和地接之間顯著的電位差造成的，地接可視為零電位。由于下列電壓差可導致損壞的發生：
■ 設備輸入端和輸出端；和
■ 內部電路和外包裝。
 重要的是必須注意，間接雷擊的影響不總是具有破壞性，它們所強加的應力是設備的使用年限降低的因素之一；使用壽命的降低是絕緣損耗、組件特性的惡化、以及開關觸點的損耗等原因造成的；

E. 28.3保護總則
對于損壞機制，信號設備的保護可以通過：
● 增加設備的非導電性，
● 在發生雷擊的時候，保證全部設備與接地具有相同的電勢；并且
● 對受影響的導線采取某些預防措施。

 目標是防止因雷擊在設備里不同的點之間引起較大的電位差，從而產生的電壓浪涌。并可能對裝置造成損壞。當遭遇到雷擊的時候，確保全部設備與接地具有相同的電勢；在電壓浪涌存在期間，通過將設備的全部終端套管，以及相臨的金屬結構連結到同一點進行保護。

 實際上，這些是通過沖擊制動裝置與一個較大橫截面銅導體，稱為一個“等勢總線”接地點連接的。

E. 28.4接地要求
所有信號系統部分的安裝必須提供地接，保護人員和設備的安全；不過由電池提供電力的內部和外部電氣電路必須與地接隔離；提供的地接保護包括：
■ 與地接的連接裝置電阻低；
■ “等勢總線”與地接連接；并且
■ 從設備到總線的地接連接線采用合適的連接方式。
   
E. 28.5信號和電信設備的接地必須分開
使用兩種類型的地接點：
(a) 管狀地接點：安裝包括：
■ 一條長度為3.50米電鍍鋼管；以及
■ 單股或雙股接線，采用鍍鎘黃銅或者銅鋁合金的半圓形方式，通過裝有夾板的螺栓和電纜連結。

這種方法允許采用多種結合方式。如果有必要降低一個地接點的電阻，可采用多根管材進行并接。 原則上，每個地接點不允許超過4根管材；通常情況下，并接的管材應該至少相隔2.50米以上。
(b) 埋設在新建大樓地基里的地接點(這個項目的價格在D段落有說明：車站和大樓建筑)：
在新建車站/設備大樓的施工期間，這類地接點包括一個埋設在地基洞穴里的環形導體。環形導體圍繞在大樓的周邊，并且以下列兩者中任何一種類型進行施工：
(i). 一個最小橫截面為25 mm2銅帶或者鉛包導體；或者
(ii). 一個至少2毫米厚，橫截面至少為25 mm2的銅帶；或者
(iii). 一條3毫米厚，橫截面至少為100 mm2的鋼帶，埋設在邊緣地帶；或者
(iv). 一條橫截面至少為95 mm2的鋼索。
銅導體的安裝必須保證和地接接觸良好。
鋼導體(鋼帶或電纜不一定要求進行電鍍)鋪設在混凝土地基里，必須有一層至少3厘米厚的混凝土。
新建信號大樓配備有埋設在地基下面地接裝置。大樓埋設的地接采用管狀地接點，用于提高地接的質量。
 如有可能，將接地點的位置設在沒有地下實用裝置的地區：例如鎧裝電纜、水和煤氣管道、下水道、大樓基礎、或者對乘客開放的地區。

E. 28.6地接的連接
安裝的地接和相鄰的信號設備必須與“總地接點”連接；連接裝置的電阻必須非常低，并且能使“總地接點”和地接之間的電勢差減到最小。
 使用在連接裝置上導體的選擇，必須根據連結的設備而定。承包商有責任對系統進行設計：系統產生的阻抗必須足夠低；常用的信號器導體的類型如下：

■ 施工現場配電箱：一個最小橫截面為25 mm2絕緣銅導體；或者
■ 施工現場配電柜和工棚：最小橫截面為25mm2的兩根絕緣的銅導體與地接網絡的不同點連接。

E. 28.7 等勢總線
 等勢總線的作用：必須保證設備的全部零件都處于相同的電勢，無論是采用直接或者通過沖擊制動裝置的中轉，防止在輸入和輸出之間，以及內部電路和安裝的套管之間產生飛弧。

 總線通過一條低阻抗的電路，將放電電流的主要部分轉入地接，防止在設備、導線和電纜間進行循環。在總線里不得有明顯的電壓降。重要的是擁有較大的銅橫截面以及相對較短的連接長度，更進一步使電壓降減少到最小；從總線到地接的連接線必須盡可能短，因此總線必須接近于地面進行安裝。

接地電阻盡可能低；對電腦化或者電信設備來說，極限電阻不應該高于1歐姆。
 等勢接地裝置的變通方法是在大樓里面安裝一個環路，包括一個最小橫截面為40 mm2的絕緣導線。該環路必須與地接點連接。

E. 28.8設備連接
 全部設備和結構必須直接連接到稱為“總地接點”的公用地接點上，可以是一根總線或者一根主要保護導線(這根導線的全度不允許斷開)。

為防止造成地接電路的中斷的相關問題，允許進行串行連接。

E. 28.9導線
 室內連接使用一根橫截面至少為2.5mm2的絕緣導線。戶外和其它類似的連接使用一根橫截面至少為10 mm2的絕緣導線。

E. 28.10 設備地接
信號系統必須與總線連接防止發生浪涌電壓。通常情況下，連接裝置為下列型號設備：
a) 機柜、支架和金屬框架的地接終端，
b) 電纜鎧裝；
c) 電源側的保護裝置；
d) 電源電池測的保護裝置；
e) 機電設備和電子設備之間保護連接裝置。
為下列專業設備，提供符合上述規格的地接裝置：
a) 繼電器室：
i). 設備機架、機柜 (包括固定設備或者類似機柜) 和電纜；
ii). 通過低電壓公用主體部分供電的設備，無論是直接與中性點或者通過插入不同斷路開關接地，將機械接地點和地接連接起來，通過地接的連接裝置連接到一起。 
b) 電纜走線架：
i). 全部走線架和電源電纜鎧裝，
ii). 信號電纜 (以及電信) 鎧裝。
c)車站主控制室：
i). 控制和指示桌面，
ii). 任何輔助設備的支架外殼。
蓄電池室內的電池電源和信號器必須與地接連接。

E. 28.11導線防護物：
各個設備的接地連接說明，必須描述各種不同的接線注意事項，進一步防止任何剩余的浪涌電壓，主要包括：
a). 將機電設備的電源電路從電子設備中分開；

 b). 從其它導線和電纜分開可能存在潛在高電流的導體，如果發生雷擊，防止在這些電路之間的發生相互干擾；

 c). 將過濾器 (一般是內置電容器) 插入與電子設備的電源連接裝置 (如果設備沒有這樣的電容器，將安裝有一臺保護裝置) ；以及

d). 在相同的燈泡里，使用多電極的沖擊制動裝置，這樣可以同時觸發。

E. 28.12 沖擊制動裝置連接
在電壓浪涌的情況下，實施下列注意事項，使設備的終端的剩余電壓，進一步減小到最小，并完全排除危險：
i.沖擊制動裝置與使用接地電極的等勢總線連接；
ii.服務于被保護的設備的電纜將直接與沖擊制動裝置連接；

E. 28.13接地漏電指示器
每個車站必須對電纜、電線和其它接地故障系統的監控設備配有至少兩個接地漏電指示器。 接地滲漏的任何監測可以通過視覺在控制面板/ VDU 表明。
 
E. 29. 環境
 施工場所的氣候溫暖并極其潮濕，非常容易發生腐蝕。年平均降雨量超過2500毫米，100毫米日均雨量是十分少見。最大的溫度變化為7ºC到45ºC。在熱帶風暴和季風期間，可能發生氣旋波，150千米/小時平均風速很常見。濕長時間度保持在90-100%范圍內，并伴有極端高溫天氣。承包商必須考慮露天高溫和高濕度，特別是密封箱子暴露在強陽光下的情況。 另外承包商必須考慮這一年內的較大降雨時期。

在夏天季節偶爾會發生較大的沙塵暴。全部戶外設備在極端灰塵的環境里，不會發生任何性能下降的情況。
 承包商必須保證全部材料的設計、施工和設備安裝，包括控制面板/VDU，適合當地氣候和天氣。承包商有責任完全熟知本地氣候狀況對系統造成的影響。

依據EN60529條款，承包商必須為全部系統部件選擇足夠的保護設備，從而適合孟加拉國的環境條件。投標商必須提交與這些要求相符的建議。
 另外，承包商必須保證，全部材料和設備都符合要求并且功能完好，并且能夠在沒有空調的情況下運行。設備的電力和機械特性承受至少+70°C的溫度。推薦的電子和電腦化設備能承受上述氣候狀況。

E. 30. 圖紙和手冊
 圖紙所使用的符號必須與在孟加拉國內使用的“鐵路符合”盡可能一致。如果需要使用特別的符號，必須給相應資料增加合適的圖例。

 承包商必須在本材料指定的時間內，或者在工程師直接指定的時間內，將包括本文件沒有具體說明圖紙、系統設計、鎖定、控制器以及電路圖或者其它任何工程師合理要求的文件提交給工程師通過。如果工程師不同意任何上述的資料或者提出的修改意見，承包商將再次提交給工程師，承包商收到的不同意和修改提議必須采用書面形式。

 承包商必須在本材料指定的時間內，或者在工程師直接指定的時間內，提供安裝手冊、現場測試的說明書、貨物和其部件的操作和維護手冊。文件必須提供足夠的細節方便業主安裝、測試、操作、維護、拆除和重建作業，并且調整這批貨物的全部部件。

 工程師對上述文件的同意或收據，并不減輕承包商對其設計、圖紙、說明書和手冊的正確性的責任，并要求完全符合本文件中貨物和相關服務的規定。無論工程師是否同意，承包商必須對負責任何變更本合同的施工作業或者，任何因與設計、圖紙以及其它的細節發生的不一致、錯誤或者省略造成的延遲交付和安裝作業，并對業主予以賠償。

在施工作業完成之后,承包商必須進行安排，并提交詳細的完工電路圖：包括流程圖、控制圖表、保險絲分析、標記端子排、導線圖表、完成架終止計劃、電纜管道計劃、位置箱子計劃、軌道電路計劃,等等。提交的文件按照工程師要求的1 + 4復印件提交，包括高分子原樣。
 
E. 31. 資料和圖紙的批準

 E. 31.1當承包商按照其信號系統的設計進行施工時，必須提交包括的每種要素的電力和機械特性的細節說明，并獲得工程師的通過。圖紙的符號必須盡可能保持一致，并符合孟加拉國使用的“鐵路符號”。在使用特別符號的情況下，必須在相應的文件中添加合適的圖例。

 E. 31.2根據詳細的時間表，承包商提供的文件包括2個復印件、計算和圖紙，在合同建規定的時間內提交工程師獲得通過。

 E. 31.3工程師必須在45日內，以書面形式批準承包商提交的任何圖紙、電路圖、或連鎖表格。如果沒有獲得通過，工程師必須在規定的時間內，提供詳細、正當的理由。承包商必須以合理的數目繼續提交圖紙；因此工程師有可能在規定的期限內，同意相同的提議。如果這些圖紙在45(45)天內沒被批準，或者沒有充分原因，在相同的時期內以書面形式給出拒絕的提議，圖紙視為被批準。

 E. 31.4工程師返還的每張圖紙的復印件必須標出“批準”或“返還再修改”字樣。

E. 31.5任何在圖紙的通過之前進行的作業由承包商自己負責。工程師有權對提交的請求附加任何細節，并且要求承包商在業主沒有額外成本而相符設計規定的情況下做出任何變更。
 
E. 31.6承包商對由于不符合條款要求，造成執行過程中的任何延遲負責。

 E. 31.7承包商提交的，工程師批準的圖紙和其它資料，并不完全構成技術有效性，但表明施工的一般的方法和描述是令人滿意的。工程師的批準不免除承包商在本合同中規定的任何責任。

 E. 31.8在合同簽署的60天內，承包商必須提交業主和工程師一份提交圖紙和資料的詳細名單和時間表。

E. 32. 安裝
 承包商必須為上述施工作業提供并且安裝全部設備和材料，并符合“交鑰匙”工程的要求。承包商負責提供技術合格的工程師、相關的技師和訓練的人員，承擔、監督、并在指定的時間內完成施工作業。工程師必須方便聯系，為承包商站點工程提供參考意見，并為承包商站點的施工作業提供放樣協助。

 車站可提供現行信號、連鎖、組塊施工作業安排，必須為火車服務的單線作業的安全要求考慮。當場地的修改變更為雙線作業時，信號安全和組塊控制系統將不起作用。在車站上方的火車運行必須采用手工方法進行管理。車站兩邊的組塊操作也恢復到手工方式。這樣的手工操作，除引起火車的延遲之外將導致顯著的安全危險。因此，這個時期應該將危險和作業計劃減到最小，并在場地作業完成后，為雙線作業引用新的信號系統。新系統將進行測試并且在一月內進行操作，根據場地的改造作業，操作開始的日期為車站信號開始運行的日期。

E. 33.任務和轉包

 E. 33.1. 除非合同另有規定，承包商不得任命或者將合同或者合同的任何部分或其利益，在沒有事先獲得業主批準的情況下，分配或者轉交給他人。

 E. 33.2除非合同另有規定，未經業主的書面同意，承包商不得將合同或者合同的任何部分轉包給他人。

 E. 33.3. 承包商必須以書面方式，將合同轉包方的全部細則提交給當事人，并提供同意轉包的性質和范圍的全部細節。如果文件已經提交，并不減少承包商在合同下的任何責任或者義務。并且承包商對分承包人的行為、失誤和疏忽負完全責任。

 E. 33.4. 如果合同的任何部分，在沒有事先經過業主同意的情況下，經承包商轉包，將視為合同違約，承包商按照有關的條款承擔責任。

E. 33.5在鐵路施工工程中，雇用任何本地人，必須以書面形式事先獲得業主同意。

E. 34. 組塊操作的工作系統
車站之間有關組塊操作的工作系統的單線和雙線路作業，必須按照孟加拉國鐵路一般規章和輔助規章的描述，執行傳統“絕對分段制” (1981版)。
 
E. 35. 進度報告
從簽署合同之日起，承包商每月發布并提供進度報告，進度報告包含執行作業的詳細信息并附上一張最新的生產時間表的一份進度報告。
應工程師的要求，舉行會議討論工程進程。
工程師能接觸信號器，證實工程進程并證實安裝的設備符合合同描述。

E. 36. 測試、試運行和工程驗收
 E. 36.1 承包商根據在條款里的說明進行車間和現場試驗。 承包商擬定一份詳細的試驗計劃并提交給工程師通過。器械操作、必要人員安排以及試驗證明書的發行，將由承包商負責相關開支。

 在試驗的開始之前至少45天內，承包商提交每個設計項目的測驗參數的詳細時間表給工程師獲得通過。工程師必須在30天內在收到試驗的時間表，將批準文書發給承包商。如果工程師沒有在規定的時期，說明不同意的任何詳細理由和原因。試驗的時間表將視為經工程師批準，測試時間為上述時期的最后一天開始。

業主的系統試運行和驗收之前，執行下列設備試驗和安裝：

E. 36.2 車間測試：
 材料和設備的測試在施工期間并且在裝運之前進行。業主和/或工程師有權隨時參觀施工現場的設備，承包商必須為這些參觀提供方便。

在沒有業主幫助的情況下，測試的執行并不免除承包商在隨后的工程作業期間出現的缺陷所承擔的責任。在工程師批準之前，工程師可以在工廠執行認為必要的全部試驗。
 
E. 36.3一般試驗：
運行測試所需要的全部儀器、電路和保護裝置。
確定控制系統功能的運行試驗。
測試確定的全部電路必須與合同批準的單個電路測試計劃相符。
電動操作設備試驗所確定的電力操作特性必須符合鐵路的要求。
全部儀器測試的電壓必須符合制造方的規格說明，以及燈具電壓的額定電壓。

E. 36.4 絕緣測試：
● 每個電路的絕緣電阻的試驗，符合鐵路制定的規范。
● 導體和電路全度之間的絕緣電阻不少于10歐姆，除非指定更高的絕緣電阻。

E. 36.5連鎖試驗：
 ● 任何部分軌道區域沒有被軌道電路的信號控制時，軌道電路區域無任何信號，并且沒有任何可以操作的的電路點。每個軌道電路部分都必須進行試驗。

● 當一個信號清晰時，沒有沖突的信號可能被清理。每個軌信號必須都進行試驗。

 ● 測試確保火車后方的連鎖得到解除，將軌道電路按照火車的通路的分接。每個軌電路都進行必須試驗，確保軌道電路能根據每個電路圖實施路線發布功能。

● 測試保證依靠這條電路，在火車通道自動取消路線的功能。

● 測試保證依靠這條電路，緊急事件的有效取消。

● 測試的鈴鐺和完整路線電路、模擬組、配電板、支架與燈具由承包商提供。
注：在連鎖測試期間，承包商至少在現場安排二名監督人校正錯誤并且檢查故障。

 E. 36.6在上述項目或者任何其它認為必要的項目的試驗開始之前，承包商必須在30天內，在試驗開始之前，制定的每個測試項目的測驗參數的詳細時間表，證實安裝的設備零件符合操作說明，并獲得工程師通過。上述工程師的批準，必須在收到試驗的時間表之后的20內提交給承包商。如果工程師不發布批準或者在規定的期限內，不詳細說明不批準的正當理由，視為自上述時期的最后一天起工程師接受試驗的時間表。

E. 36.7系統驗收：
 在系統或者其部件準備好驗收至少15天之前，承包商必須以書面形式通知工程師。在上述通知日期30天內，工程師和承包商將一起參與并且完成驗收試驗。如果工程師沒有參加試驗，承包商將有權進行并且完成試驗，并且即刻將測驗結果寄給工程師。在試驗完成的15天內，或者承包商在工程師不在場的情況下，工程師必須在15天內，將是否通過的測驗的書面通知提交給承包商。在表示整個信號器的臨時驗收合格之前，工程師可能進行他可能認為必要的完整的信號系統的全部試驗。

如果系統或者測試部件由于沒有滿足合同要求的規定，沒有被業主接受，上述的書面通知必須指定聲稱的、存在或者發生缺陷處的細節。如果有要求，在測試過程中根據這項條款的規定，承包商必須以合理速度對相關或受影響的部件重復進行測試。驗收不得以不影響系統使用的微小缺陷，拒絕驗收，不過，這并不免除承包商對缺陷進行補救的義務。
 
E. 36.8信號器驗收：
 在整個信號器的試驗已經完成并且宣布滿意之后，必須將一份系統的臨時的驗收合格證交付給承包商。在任何情況下，在試驗期間發現的全部不符合功能要求處已經被修理之后，整個系統的臨時的驗收合格證才能進行交付。

 工程師已經發現的全部功能缺陷，必須在年末，在業主所出具一份最終驗收合格證前，進行糾正。 

雙線運行信號系統的試運行(承包商的接受工作)只有在軌道、橋梁、車站大樓和有關的設備和新信號系統完成，經過測試，適于工程師對火車設施進行安全操作之后開始。
 

 部分接管和部分雙線運行的信號系統的操作，必須在連續3個車站(無論是從Tongi或者從Bhairab 市場開始，或者同時從兩個車站開始)的作業已經完成，并且通過測試，適于工程師的火車設施進行安全操作之后開始。

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
 
 
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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