Railway Signal Engineering

  RDPMS - Real diagnostic and Predictive maintenance system Least count of Varnier Calipers-0.1 m Least count of micrometer -0.01 m Least count of feeler gauge - 0.05 mm to 1 mm. Lathe Machine is a Machine tool that is used for shaping metal or wood.It works by rotating the workpiece around a stationary cutting tool. The main use is to remove unwanted parts of the material, leaving behind a nicely shaped workpiece.Tail stock is the part of Lathe Machine which holds drill. Pitch of a Screw Gauge   - Distance moved by a spindle per revolution. Pitch of screw gauge = Distance moved by Screw/ No of rotations given Rolling and Forging   - Forging is a manufacturing process in which metal is heated and then shaped using hammers or presses. If forging is done in die It is called Impression dia forging.Impression word refers to pre cut profile of the die used during forging process, which are based on part that is being produced. Process in Impression dia forging-  Fullering- The first step to

  Class A - Where line clear may not be given for a train unless the line on which it is intended to receive is clear for at least 400m beyond the Home Signal or upto Starter. Class B -Where line clear may  be given for a train before the line has been clear for the reception of the train within the station section. Class C   Station or Block Huts- Where permission to approach may not given for a train unless the whole of the last proceeding train has passed complete at least 400 m beyond the Home Signal ( IBS/IBH) and is continuing its journey.  This will also include an Intermediate block post. Spl class Station - SWR signed by CRS .

  Codal life -20 years DSU ( Digital Scanner Unit) Each DSU contains 8 no of digital input cards. These scanner cards contain opto couplers and multiplexer. Each input card - 64 Inputs Total input capacity of one DSU unit is 512 inputs (inbuilt) Display of digital inputs in 32 row 16 column display. Maximum 7 nos additional DSUs can be can be connected to the system so digital input capacity is 4096. All this digital inputs are scanned at rates of 16 m sec. ASU ( Analog Scanner Unit) ASU contains maximum 3 nos of Analog input cards. Each input card can be connected with 8 nos of Analog Inputs. Total input capacity of the ASU is 24 Analog input channels. Maximum 4 nos of ASUS can be connected to the system.Analog input channel capacity of the system is 96. All these Analog inputs are scanned at rate less than 1 sec. RS 232 Serial  Ports At least 6 serial communication ports are provided for communication with other dataloggers, Central Monitoring Unit, Remote Terminal Unit,EI system, IP

  For Existing Works-   Horizontal Distance of any fixed structure (upto 305 mm height), from centre of track - 1675 mm From 305 mm to 4520 mm - 2135 mm. Max height of any  signalling gear between track lines - 64 mm . SOD of the Signal  - SOD of a signal is measured from outermost part of the Signal.Outermost point is generally ladder. For new work-  Rail level to 305 mm above rail level -1905 mm. From 305 mm to 1065 mm - 2360 mm .( Distance of Signal Post from centre line of track) From 1065 mm to 3735 mm - 2360 mm. Existing yard - gradient is steeper than 1 in 400 and upto and upto 1 in 100 -  CRS Permission is required  If gradient is steeper than 1 in 100 - Railway Board through CRS. New yards or New Work -  In Station Section, Maximum Gradient recommended is 1 in 1200. For Single line, Station yard will be extended to a distance of 50 m beyond outermost points at either end of the station.( For purchase of maximum gradient Permitted). In block section, Steeper than 1 in 400 and u

Fully Charged lead acid  Cell Voltage - 2.2 V, Gravity - 1220+/- 5 Discharged lead acid Cell Voltage- 1.85 V, Gravity - 1180+/- 5 Elctrolyte -Dilute Sulphuric Acid Positive Electrode - PbO2, Negative Electrode - Sponge Pb Input Voltage of SMR- (160-270) V AC Initial Charging Voltage - 2.7 V/Cell  Initial Charging Current- 4% of capacity Float Charging Voltage - (2.12-2.3) V/Cell Boost mode equalizing charging - 10% of AH Capacity  In RE area- Safety factor -1.5 Safe handling voltage - 400 V  Induced voltage in underground unscreened cable   1) On a single line section -for the catenery current of 800 Amps is 116 v/ km . 2) On a Double line section- for the catenery current of 1000 Amps is 95 v/ km 2 m from contact wire - iron mess required  Iron mess - separate earth less than 10 ohms. Height of contact wire - 5.55 - 5.75 m from rail level  2360 mm is distance for signal implantation and OHE mast also Contact wire and catinary are parallel Height of Red Aspect -3.65 m. Quad cable is jo

                                                    Basics of Telecom STM - Synchronus Transport Module  STM 1 link has 63 E1. 1 E1 = 30 Channel   E1 stream has bandwidth of 2 Mbps.E2 stream has bandwidth of  8 Mbps STM 4 can accommodate 252 E1. Difference between PDH and SDH PDH stands for plesiochronus digital Hierarchy.PCM multiplexer used in PDH.   It is Telecommunications network transmission technology designed for the transport of large data volumes across large scale digital networks. In PDH, multixiplexing of 2 Mbit/s signals into high order multixiplexied signals. The laying cables between switch sites is very expensive.It increases traffic capacity of a cable by increasing bit rate.Used to transmit voice conversations.Use Time division multiplexing.It has 4 type of frames. E1,E2,E3 and E4.Use coaxial cable or twisted pair copper wire. SDH stands for Synchronus digital Hierarchy.Used to transmit voice and data over Optical Fibre.  It refers to as multiplexed technology used i