In the first major downpour since the arrival of monsoon in Mumbai, heavy rains lashed the city today disrupting rail traffic. The MeT department in Mumbai said that the maximum rainfall was observed in the suburbs, with Kandivili and Malad receiving around 45 mm rainfall.Colaba recorded 21 mm rainfall and Santacruz recorded 75 mm downpour till 9 a.m. today, it said. The department has warned that heavy to very heavy rains may occur in the Konkan and Mumbai coasts during the next 24 hours.Central Railway trains which were running late by 30 to 35 minutes earlier, because of signal problems at various locations, are now running normal.All suburban train services were running on schedule on the western line. Most flights are running normal at the Mumbai international airport and there are no disruptions reported so far.