Heavy rain and waterlogging triggered disruptions on Mumbai Suburban Railway’s Trans-Harbour line, leaving thousands of commuters stranded between Thane and Navi Mumbai. The soil and ballast beneath the rail tracks caved in between the Turbhe and Koparkhairane stations, raising safety concerns.The southwest monsoon arrived in Mumbai on Tuesday. (HT PHOTO)Central Railway (CR) officials said services were immediately suspended on the Turbhe-Koparkhairane section on the Trans-Harbour corridor. “The up line was declared unsafe for train movement at 5:06am, followed shortly by the down line at 5:50am, completely halting the flow of traffic on the crucial Thane-Vashi corridor,” said an official.Emergency engineering teams were deployed to stabilise the track bed amid continuing rains. Following urgent restoration work, the tracks were cleared for limited operations.“The up line track was declared safe at 7:27am with a severe speed restriction of 10 kmph on passing trains. The down line was cleared soon after at 7:35am, allowing local services to resume at a restricted speed of 30 kmph,” said CR chief public relations officer Swapnil Nila.The hours-long disruption hit daily commuters, particularly office goers travelling between Thane and the IT and commercial hubs of Navi Mumbai. Huge crowds waited at platforms across the corridor. Even after services resumed, trains crawled through the affected section, causing cascading delays of over 30 to 45 minutes across the network.Waterlogging was reported between Kurla and Matunga on the main line, leading to delays in train services by 10-15 minutes. Railway officials said that teams are continuously monitoring the spot to ensure structural stability.The southwest monsoon arrived in Mumbai on Tuesday, 12 days after its usual onset date, bringing relief from the sweltering heat. This was the joint third-most delayed monsoon onset in Mumbai since 1951.