Scope of Work:	GPR survey execution for mapping underground utilities to ensure 30 m wide clear stretch for smooth installation of new pipeline in Dahej
Location:	Chhatrapati Shivaji Terminal Railway Station, Mumbai, India.
Client:	Indian Railways
Equipment:	GSSI SIR-3000 equipped with 900 MHz and 400 MHz antenna
Challenges:	Data collection on railway track using conventional GPR system
Summary:	The GPR investigation has been carried out along the two stretches of length 95 m and 155 m on platform no. 12 at Chatrapati Shivaji terminus Railway station, Mumbai to inspect the railway ballast. The objective of the survey was to map the possible scrap material eg. rail piece, concrete block, Optical fiber cables, signal transmitting cables and other metallic and non-metallic object material in the ballast using GPR. It has been observed that during the screening of ballast using the Ballast cleaning machine, the presence of scrap in the ballast hinder the capacity of the machine as well as hampers the further screening work resulting in very less output than expected. Moreover, it does damage the existing cables which lead to great damage to the overall functioning of the railway system. Therefore, through this survey, the ability of GPR to map the scrap non-destructively has been explored so that, the possible scrap can be removed manually or the damage to the cables can be avoided, hence improving the efficiency of the ballast cleaning machine. A customized data collection mechanism was developed specifically for smooth movement of GPR system over railway tracks. The GPR survey was carried out followed by BCM operation. The output of the GPR survey were found to be 100% accurate in practical scenarios as well.