A commuter wearing a raincoat wades through waterlogged General Patters Road amid heavy rainfall, in Chennai. (ANI Photo)Heavy rain is expected to continue across Kerala and Tamil Nadu over the coming days, with the India Meteorological Department (IMD) issuing orange alerts for several districts and warning of very heavy rainfall in isolated areas.Kerala rain updateIn Kerala, Thiruvananthapuram, Kollam, Pathanamthitta, Alappuzha and Palakkad are among the districts under yellow alert for the next 3 days. Kottayam is under a yellow alert till October 24, while Wayanad is expected to receive heavy rain over the next three days. Kannur and Kasaragod are also under yellow alerts. Weather map. (Source: IMD)The weather department has issued orange alerts for Thrissur and Ernakulam, warning of heavy to very heavy rainfall. Ernakulam is under an orange alert on Thursday, followed by a yellow alert on Friday and Saturday, before the warning level rises again on Sunday. Idukki is under a yellow alert for the next three days, with an orange alert expected on October 25. Malappuram and Kozhikode are under orange alerts on Thursday, followed by yellow alerts over the next two days, according to the latest weather bulletin.Thunderstorms, lightning and gusty winds are also likely in parts of the region over the weekend.Tamil Nadu rainIn Tamil Nadu, the northeast monsoon has brought heavy rain to Chennai and surrounding districts. Schools were shut in Chennai, Tiruvallur, Kancheepuram and Chengalpattu on Wednesday.The Regional Meteorological Centre has forecast more rain over the next 48 hours. A low-pressure area is likely to form over the southwest Bay of Bengal, close to the Tamil Nadu coast within 24 hours. The system is expected to develop under the influence of an upper-air cyclonic circulation over the same region. Southwest monsoon map. (Source: IMD)The IMD has forecast very heavy rain in isolated areas of Puducherry and Karaikal till Sunday. Isolated heavy rainfall is also likely on October 26, while thunderstorms, lightning and gusty winds may continue across the region through October 26.Story continues below this adKerala landslide derails locomotiveHeavy rain has also disrupted rail services in southern Kerala. A landslide near Parassala railway station in Thiruvananthapuram district derailed the locomotive of the Bilaspur-Tirunelveli Express early Thursday.According to a PTI report, the incident took place at 2.19 am after the train was stopped near Parassala. Southern Railway said all passengers and railway staff were safe.An accident relief train and a replacement locomotive were deployed to assist with the restoration work. Train services in the Neyyattinkara-Parassala section resumed at 8.10 am after the tracks were restored and safety inspections completed.However, six passenger trains were cancelled, and routes of two Amrit Bharat Express services were cut short or diverted to originate from Nagercoil Town. The Bilaspur-Tirunelveli Express was also terminated at Neyyattinkara, with buses arranged to transport passengers to their destinations.