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| Type | Commercial Circular |
|---|---|
| Topic | ticket-checking |
| Currency | Currency not verified |
urban sections and very heavy density routes where the trains have to follow in quick succession * When an Automatic stop signal is at danger the LP shall bring the train to a stop as close as possible in rear of the signal.
**The Automatic Block System (South Western Railway)** ### Salient Features- 1. It is the second widely adopted system on Indian Railways. 2. It is followed mostly on the sub-urban sections and very heavy density routes where the trains have to follow in quick succession. 3. The line is provided with continuous track circuiting or axle counters. 4. The signals are of multiple aspect colour light nature displaying three or four aspects. 5. Provision of four aspect automatic signalling with inter-signal distance of 800 metres will improve the line capacity from the present 2.2 to 2.4 trains per hour to approximately 5 to 10 trains per hour. This becomes possible as each block section will permit a large no of trains following each other and the operational time for the signalling equipment at stations is reduced to the barest minimum. Some sections of South Western Railway where Automatic Block System is in force (S.R. 9.01(i)) | | | | --- | --- | | **Double line** | **Single line** | | Bangalore City – White field | NA | **Difference between Absolute block system and Automatic block system** | | | | | --- | --- | --- | | **Sl. No** | **Absolute Block system** | **Automatic Block system** | | 1 | The most widely system used in Indian Railways. | The second widely used system mostly in Sub-urban sections and on sections where trains follow in quick succession. | | 2 | There shall be only one train at a time in one block section. | More than one train may be permitted in one block section. | | 3 | Line capacity is less. | Line capacity is more. | | 4 | Signals are manually operated. | Signals may be operated automatically. | | 5 | Provision of track circuits or axle counters is not mandatory. | Provision of track circuits or axle counters is mandatory. | | 6 | The normal aspect of Stop signal is Danger. | The normal aspect of Automatic stop signal is Proceed. | | 7 | Signals may be Two aspects or Multiple aspects. | Only Multiple aspect signals are provided. | | 8 | Stations are classified as A, B, C, D or special class. | All stations are special class . | | 9 | Station working rules of some stations may not be approved by CRS. | Station working rules of all the stations shall have the approval of CRS. | | 10 | Stop signals shall not be passed at ON by LPs without written authority. | Automatic Stop signals may be passed at ON by LPs without written authority. | | 11 | Block Instruments are provided for obtaining and granting Line clear. | Block Instruments are not provided. | | 12 | GDR need not undergo Orientation course to work in this system. | GDR need to undergo Orientation course and obtain certificate to work in this system. | | 13 | Operating forms like T/C 1425, T/D 1425, T/B 602, T/E 602 etc. may be used in Automatic block system also. | Operating forms viz. T/A 912, T/B 912, T/C 912 and T/D 912 shall not be used in Absolute block system. | | 14 | Centralized traffic control cannot be provided. | Centralized traffic control may be provided. | | 15 | Protection during accidents is done by placing one detonator at 600 mts and three detonators 10 mts apart at 1200 mts from the place of obstruction on the rails. | Protection is arranged by placing one detonator at a distance of 90 mts and two detonators at a distance of 180 mts from the place obstruction on the rails. | **Essentials of Automatic Block System –Double Line (Rule 9.01)** # 1. Line shall be provided with continuous track circuiting or axle counters. 2. Line between adjacent block stations may, where required be divided into series of signalling sections by provision of Automatic Stop Signals. 3. Entry of train into each signalling section is controlled by a stop signal. 4. The Signal shall not assume “OFF” aspect unless the line is clear up to the next Automatic Stop Signal plus an adequate distance. 5. The Signal shall assume “ON” aspect automatically as soon as the train passes it. 6. Unless relaxation is given by CRS the adequate distance ment
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