Section 9(4) in The Calcutta Metro Railway General Rules, 2000
(4)A lorry or a material/push/Motor trolley shall be run-(a)during non-traffic hours under conditions of clear visibility and under power block or(b)during traffic hours when track possession has also been taken of that section by the engineering official-in-charge and traction Power Controller has confirmed that the traction current on the section has been switched off.
