Section 17(4)(viii) in The Bangalore Metro Railway (General) Rules, 2011
(viii)each employee of the Bangalore Metro Railway involved in the shunting of work trains, the operation of work trains at a maintenance site and the operation of work trains within an Engineer's Possession, shall carry a hand lamp capable of displaying Red, Green and White aspects in working order and shall be conversant with its proper use and in addition, he shall also carry a Red flag and a Green flag.