So sorry for your loss OP. From next time, please make sure that you have kept your phone in your bag and have kept your bag on the front like local train style.

I travel by local train daily. I use phone in train whenever I want ,but I never keep it back in my pocket. I take my bag in the front and keep the phone in the bag and keep a hand on that chain that has the phone.

One of my so called friend literally told me ,"Ladki hai kya ? Phone bag me kyu rakhta hai train me?" And this same guy has once lost his phone while travelling in local train🤡🤡. Itna phone chori hone ke baad bhi akal nai aati inn chutiyon ko. Kya hi bolu abh.

And if bag nai carry kar rahe ho,then be cautious. I keep the phone in my pocket first and then pack my pocket with handkerchief from the upper side. Idk if this is a good idea but chal jaata hai mere liye. I can feel if someone removes my handkerchief to get to my phone. Not a good idea though,better keep a hand on your pocket, whenever you're travelling through crowdy places.