I tried to use ₹10 coins in Durgapur, they refused to accept it. Caught 12019 till Dhanbad where too the story isn't different. From Dhanbad 68020 to Bokaro, none ready to accept in station. My friend coming from Sector 9 used them easily. Same train to Purulia, few stalls accepted and most didn't. I asked there, they replied fear of wide acceptance. One of my mate said the situation is bitterly same in Jamshedpur as well.
I sometime feel to primarily use cashless methods if the network tends to be stable everywhere.:(