Automatic Block Signalling PDF

IRISET BLOCK SIGNALLING LABORATORY EXPERIMENT No: BSL - 20 Name : ___________ ____ Roll No : _______________ Marks Awarded : Course : _______________ Date...

IRISET BLOCK SIGNALLING LABORATORY EXPERIMENT No: BSL - 20 Name : ___________ ____ Roll No : _______________ Marks Awarded : Course : _______________ Date : _______________ Instructor Initial : Automatic Block signalling A) INTRODUCTION Automatic Block Working is a system of train working in which movement of the trains is controlled by the automatic stop signals. These signals are operated automatically by the passage of trains into through and out of the automatic signalling sections. The following are the essentials of Automatic Block System. Where trains are worked on Automatic Block System: - (a) The line is track circuited or axle counters are provided throughout its length and divided into a series of automatic signalling sections each of which is governed by an Automatic Stop Signal. (b) The movement of trains is controlled by stop signals, which are operated automatically by the passage of train past the signals. (c) No Automatic Signal assumes 'OFF' unless the line is clear not only upto the stop signal ahead, but also an adequate distance beyond it. The Automatic Signalling arrangement facilitates to Increase the Line capacity without any additional Stations being constructed and maintained. B) ADVANTAGES Line capacity increases. Less dependence on human agencies. No need to issue authority when automatic signal is at ON, Automatic stop signal can be passed at `ON' position as per General Rule 9.02, after stopping one minute by day and two minutes by night. IRISET / BSL - 20 1/8 C) Markers used in Automatic stop signal: 1) ‘A’ marker in Automatic stop signal:  A marker in black colour on white back ground is provided for all Automatic Block signals.  Semi Automatic signal is provided with illuminated ‘A’ sign.  Illuminated ‘A’ sign will lit when signal is working as Automatic stop signal.  Illuminated ‘A’ sign will not lit when signal is working as a manual stop signal. A A Automatic signal Semi Automatic signal Fig: 1 Fig: 2 2) ‘A’ & ‘G’ Marker used in Automatic Signalling at LC Gates Level Crossing Gate signal (When no point in the route)  Yellow circular disc with ‘G’ letter in black and illuminated ‘A’ letter against black background are provided.  Illuminated ‘A’ sign of the Semi-Automatic gate signal will lit when the level crossing gate is closed against the road traffic and signal is working as an Automatic stop signal. Fig: 3 IRISET / BSL - 20 2/8  3) Level Crossing Gate signal (When points are in the route)  Illuminated ‘A’ and ‘AG’ sign are provided on gate signal.  Illuminated ‘A’ sign will lit when level crossing is closed against road traffic and points in the route are correctly set and locked and signal is working as an Automatic stop signal. Fig: 4 Illuminated ‘AG’ sign will lit when points in the route are correctly set and locked and LC gate is defective and signal is working as an Automatic stop signal. D) Automatic Signalling Sections 202 204 206 208 A A A A AUTOMATIC OVERLAP SIGNALLING 120 Mts SECTION Fig: 5 AUTOMATIC SIGNALLING SECTION The automatic Signalling Section is defined as the portion of the running road between any two consecutive automatic stop signals and each of these sections is protected by an automatic stop signal. These automatic stop signals control the movement of trains into the sections and operate automatically by the passage of train past the signals. IRISET / BSL - 20 3/8 E) Adequate Distance or Overlap and Berthing track in Automatic Signalling The adequate distance which may also be termed 'overlap’, shall not be less than 120 meters unless otherwise directed by approved special instructions. 204 206 208 A A A OVER LAP BERTHING TRACK TRACK OVER LAP BERTHING 120 Mts TRACK TRACK AUTOMATIC AUTOMATIC SIGNALLING SECTION SIGNALLING SECTION Fig: 6 OVERLAP AND BERTHING TRACKS The essentials of Automatic Block System stipulates that an Automatic Stop Signal can assume OFF aspect only when the line is clear not only up to the next signal but also an adequate distance beyond it. This defines an overlap of 120 meters (minimum) in advance of every Automatic Signal to be clear before the signal in rear can change its aspect from 'ON' to 'OFF' in addition to the distance between the two signals. So it becomes necessary to define the end of overlap in advances of every automatic stop signal and hence, the track circuit is bifurcated at 120 meters from the signal as shown above and this 120 meters track is called the "overlap track" and the remaining track length is called the "Berth Track" in each signalling section. F) Four-Aspect Automatic Signalling Generally when the automatic signals are provided with distance between the signals not less than breaking distance, then 3-aspect signals will serve the purpose. But if the distance between two consecutive signals is less than breaking distance On account of stations being very close or to improve the section capacity by reducing the headway between trains and reducing the automatic signalling sections, then the automatic signals have to be provided with 4 aspects. In this case, the sequence of aspects, when a train passes a signal is Red, Yellow, double Yellow and Green as the train occupies the section after passing a signal and clearing one section, two sections and 3 sections ahead of the signal respectively. The arrangement of signalling is shown in Fig.7. 1 3 5 7 A A A A 1T 1 AT 3T 3 AT 5T 5 AT 7T 7 AT Fig 7 Four aspect Automatic signalling IRISET / BSL - 20 4/8  When a train passes signal No.7 and is occupying the section 7AT then signal No.7 displays Red (danger) and the signals in rear display the aspects as indicated below: - Signal No.5 - Yellow (Caution) Signal No.3 - Double Yellow (Attention) Signal No.1 - Green (Clear) As these signals have one, two and three sections ahead clear. In this system of 4 aspects signalling, it is customary to ensure that the distance between the signal displaying red and a signal displaying caution aspect is at least equal to breaking distance. G) Automatic Signal Circuits 1 3 5 7 9 A A A A A A 1T 1AT 3T 3AT 5T 5AT 7T 7AT 9T 10T 8AT 8T 6AT 6T 4AT 4T 2AT 2T A A A A A 10 8 6 4 2 A Fig 8 Automatic signalling layout for double line B 24 3 TPR 3 RECR N24 3 3 GECR HECR 3 HHECR 3 DECR 3 B24 HECR N24 3 3 ECPR1 HHECR 3 DECR 3 3 3 B24 HECR HHECR ECPR1 N24 3 3 ECPR2 DECR Fig 9 GECR, ECPR1 and ECPR2 circuits IRISET / BSL - 20 5/8 3 GECR pick up condition proves Signal not blank and its front contact proved in HR circuit of rear signal (Red Lamp Protection). Controlling Circuit for Signal No 1 3 GECR relay picks up when it is displaying any one of the aspects namely Green, Double yellow, Yellow or Red. This relay is repeated as 3GECPR relay at signal No.1 location. 3GECPR relay pick up contact is proved in I HYR and 1 HR circuits, to prove Red lamp protection for signal No.3. 3 ECPR1 picks up when Signal No.3 is displaying any one of the OFF aspects namely Green, Attention aspect or Caution aspect Yellow. This relay Pick up contact is used to control 1HHR for proving signal No.3 Attention Aspect. 3 ECPR2 picks up when it is displaying either Green or Double yellow aspect. This relay Pick up contact along with 3 ECPR1 are used to control 1DR relay for displaying clear aspect. SIGNAL-1 SIGNAL-3 3 GECPR B24 1 HYR AHEAD SIGNAL 3 NOT BLANK GECPR N24 1 3 3 HR ECPR1 HR 1 AHEAD SIGNAL HHR 1 3 3 IS 'Y' & HR ECPR1 HR SECTION IS CLEAR 1 3 HHR ECPR2 1 AHEAD SIGNAL DR 1 3 IS 'YY' OR 'G' ECPR2 HHR & SECTION IS CLEAR 1 1 1 1 1 1 1A 1 N24 DECR HHECR ECPR2 HECR ECPR1 HYR TPR TPR B24 1 HR 1 HR Fig 10 HR Circuit When 3 GECR relay picks up at signal No.3 location, proving Sig No.3 is displaying any aspect and 3TPR is up there by 1HYR relay at Sig No.1 location will pick up. With 1HYR relay pick up 1HR relay will pick up proving 1TPR. 1ATPR up and signal No.1 OFF aspect lamp proving relays are down that is 1 DECR ,1HHECR IRISET / BSL - 20 6/8 ,1HECR along with 1ECPR1 and 1ECPR2 is down makes 1HR to pick up, it has a stick path with its own front contact by passing 1DECR, 1HHECR,1HECR, ECPR1 and ECPR2. Once 1HR is up, proving ahead signal No.3 HR and 3ECPR1 are up thereby 1HHR relay picks up. By proving 3HR, 3ECPR1 and 3ECPR2 pick up contacts 1DR will pick up. All three controlling relays of signal No.1 HR, HHR and DR remain picked up when the entire section is clear. As soon as train passes signal No.1, 1HR will drop and replaces the signal No.1 to danger. H) EXERCISE: 1) Write about advantages of Automatic signalling? 2) What is the procedure of train working for passing automatic signal at danger? 3) Write about adequate distance or overlap in Auto signalling? 4) What are various marker used Auto signalling and give details? 5) What is berthing track in Auto signalling? IRISET / BSL - 20 7/8 6) Draw the layout of lab model for Automatic signalling. And mention how many signals are with ‘A’ marker and how many with ‘A’ board? Date: Signature of the Trainee IRISET / BSL - 20 8/8