Railway Signal Engineering

Government expenditure is divided into two parts- 1. Voted - made from consolidated fund of India  2. Charged - Charged from consolidated fund of India.  Article 113(1) - Charged Expenditure is not subjected to vote of parliament. Article 113(2) of Constitution -  Voted expenditure Abstract Estimate - For obtaining Administrative Approval  Detailed Estimate - For obtaining Technical Sanction of competent authority.Cost should not exceed Abstract Estimate.Prepared in sufficient Detailed.Detailed Estimate is not required for work less than 5 Lakh. Supplentary Estimate - An item of work, which is found later,should be considered as being a part of an estimate already prepared and sanctioned. Revised Estimate -  1. If the expenditure on a work likely to exceed the sanctioned cost. 2. Prepared and submitted for sanction of the competent Authority. 3. Prepared based on earnings/ expenditure trends of first five months and projections for the balance period. For open ...

  SM fibre ( Single mode fibre)- It is a type of fibre optics cable that has smaller core diameter compared to multimode fibre. This means only a single mode of light can travel through it,resulting less signal loss and higher bandwidth. It transmits a single ray of light,which has higher bandwidth capabilities and preferred in longer distance applications. Multi mode Fibre Optic Cable- Large diameter core that allows multiple modes of light to propogate. As the core increases,more data passes through a given time. Quality of signal reduced over long distances. Typically used for short distances,data and audio/video applications in LANs. Windows of OFC - 1 st window - 850 nm - Short wavelength region 2 nd window - 1310 nm - Medium wavelength (O band) 3rd window - 1550 nm - Long Wavelength (C band) Attenuation is minimum at 3 rd window. 2nd and 3rd window are used in Single Mode Fibre. 1st and 2nd in Multi mode Fibre. Max speed of Cable laying in OFC - 15 meter/ min. Link power budg...

System that facilitates dissemination of train related information to passengers are passenger Information System ( PIS) System that provides information at Railway station Premises - 1. Audio : The train related information like arrival/ departure announced through PA system. 2. Video: The information provided through video system.This is of two types. a. Interactive Video system:  It is Graphic user interface ( GUI) based touch screen directly operated by passenger to get information. These are called Passenger operated Enquiry Terminals (POET) or Touch Screen Display system. b. Non Interactive Video system - Provided train related information on CCTV monitors. These systems also display intertainment program like TV channel broadcasting. 3. Alphanumeric display systems-  Gives information in different languages on platform.This information guides the passengers to go to correct platform and in time. System that provides information at Passenger end- Two types - Interactive ...

  Size of Cable - The various size of conductors used in Cable are - 0.4 mm,0.51 mm,0.63 mm,0.9 mm and 1.2 mm. Twisting is done to avoid crosstalk. Distortionless condition- If there is no phase Distortion, the velocity of propogation must be same for different Frequency components and should be independent of Frequency. GL=RC is distortionless condition  Loading of Underground cable - When diameter of conductor increases,  value of R decreases . This is not possible due to its increased cost. If the value of G increases, transmission loss will increase which is also not acceptable. Therefore there is only one way to increase the value of GL by increasing L.This is achieved by using the coils of suitable inductance value wound on dust cores are placed in series with line on suitable intervals. This is called coil loading or lump loading.Value of each coil connected in each limb of a quad cable is 59 mh. V.F.balancing of underground cable - V. F balancing of underground ca...

Connectors- Two most common connectors used for professional audio are 3 pin XLR and 1/4 phone connectors. RCA Connectors- A round,press on connector used for audio and video connections. F connectors- used for television and antenna applications. N connectors- used by  cable TV industry.N means Navy. C connectors- Similar to N connector. However they are Bayonet locking. BNC Connector-( Bayonet Neil Conelment connector) RF connector used for terminating coaxial cable. Used in video and RF applications to 2 GHz. TNC connector- Threaded version of BNC connector  Used in cellular telephone RF antenna connections. Waveguide Tees - Waveguide Tees are Waveguide junctions. 1. E type T junction  2. H type T junction.  Attenuator - Used to Control the amount of power transferred between the  points on a transmission line by absorbing or reflecting some of Microwave power. Directional Coupler- It is four port component in which two transmission lines are employed in suc...

  PTCC - Power and Telecommunication Co-ordination Committe. Central standing committee for co-ordination of Power and Telecommunication system. Local Telephone Equipment ( LTE). LTE is used to provide 20 local telephones at HQ. Types of cables  A) Quad Cable 0.9 mm or 1.4 mm dia. 1.4 dia Quad used for Block Section more than 12 kms. Suitable for underground laying. Used for control Circuits and block interfaces. IRS Specifications IRS: TC 30/05 B) PIJF cable-  Multi pair ( from 10 pairs to 200) Multi dia ( 0.5 mm/0.63 mm/0.9 mm) Suitable for underground laying. Used for exchange subscriber lines or branch cables branching off from main quad cable. C) Twisted Pair Switch Board Cable ( 0.5 mm/0.6 mm) Not designed for underground laying. Used for indoor applications such as distribution to various telephone subscribers in a building. Jointing Kit- For quad cable jointing- RTSF ( Reinforced Thermo Shrink Jelly Filled kit) type jointing kit to be used. Laying - Quad cable ...