Railway Signal Engineering

Grants - The demand for grant as finally approved by the Parliament are called Budget Grant. Appropriations (Charged) - Those sanctioned by President without reference to parliament are called Appropriations. Budget Order - Railway grants and Appropriations for a year are distributed by Railway Board to various Railway Administrations directly under Railway Board through Budget Orders. Budget Allotments -  G rants and Appropriations distributed to various Divisions and spending units are called Budget Allotments 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 Estimat...

  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...