Rail transport in India - Wikipedia
Railways is giving a big thrust to infrastructure creation and capacity augmentation. Railway Projects are taken up on the basis of remunerativeness, last mile connectivity, missing links and alternate routes, augmentation of congested/saturated lines, socio-economic considerations etc. depending upon throwforward of ongoing projects, overall availability of funds and competing demands and sanctioning of projects is a continuous process.
Railway Projects are sanctioned Zone-wise and not State-wise, as, Indian Railway’s network is straddled across various State boundaries. Further, details of ongoing Railway Projects in the country including Southern Railway is appended and with progressive commissioning of sections, existing rail network would also expand accordingly.
The project-wise detail including cost, expenditure and outlay are available in public domain on Indian Railways’ website i.e. www.indianrailways.gov.in >Ministry of Railways >Railway Board >About Indian Railways >Railway Board Directorates >Finance (Budget) >Pink Book (year) >Railway-wise Works Machinery & Rolling Stock Programme.

BUDGET ALLOCATION ON INDIAN RAILWAYS 
Average Annual Budget allotment for New Line, Gauge Conversion and Doubling Projects on Indian Railways, during 2014-19 has increased to Rs. 26,026 crore, from Rs. 11,527 crore (during 2009-14), which is 126% more as compared to average allotment during 2009-14.
Total Budget Estimate (BE) Outlay for New Line, Gauge Conversion and Doubling Projects on Indian Railways in 2019-20 was Rs. 30,198, which has further been increased to Rs. 38,803 in Revised Budget Outlay. This is 237% more as compared to average annual budget allotment during 2009-14. (Rs. 11,527)

COMMISSIONING OF NEW LINE, GAUGE CONVERSION AND DOUBLING
During 2009-14, 7599 km length (New Line, Gauge Conversion and Doubling) has been commissioned on Indian Railways. Further, during 2014-19, 13,124 km length (New Line, Gauge Conversion and Doubling) has been commissioned on Indian Railways, which is 73% more than commissioning during 2009-14. Details of New Lines, Doubling and Gauge Conversion in the Country is as under:-

ONGOING NEW LINE, GAUGE CONVERSION AND DOUBLING PROJECTS:
Plan HeadNo of ProjectsTotal Length (in km)Length Commissioned till Mar'19 (in Km)Anticipated Cost (` in crore)Total Exp upto Mar'19 (` in crore)Budget Estimate Outlay for 2019-20 (` in crore)
INDIAN RAILWAYS
New lines1882129526223,87,1548553614848
Gauge Conversion557275357356135196403465
Doubling2552050027842,31,9784834218301
TOTAL4984906989796,75,2671,53,51836614