On the train with my guide dog

I have a guide dog. Once on a train, two teens (12-14 y, male) looking for trouble were harassing passengers. As I ignored them, they pinched my dog. The dog went to sit in the aisle to get away from them. I put my leg across the aisle to block their access to him and told the boys firmly: “now you stop and you leave him alone”. They gave up and got off the train at the next stop.