Central Railway will conduct a mega block on Mumbai suburban sections on January 4 for engineering and maintenance work. This will affect services on the Main Line between Matunga and Mulund, causing delays of approximately 15 minutes for UP and DOWN slow line trains. Trans-Harbour Line services between Thane and Vashi/Nerul will also be suspended, with some services cancelled entirely. Passengers are advised of potential inconvenience due to these essential infrastructure upkeep measures.