OK, I hosted a session for a friend and I. We both did our yard work and took consists out from opposite end of the route. When he pulled to a siding and I passed him, he never saw a train. He had to go to the drivers windows and view me to then have my train appear in the correct position along the line. Until he did this it still showed me in the yard at the end of the route. I DID see him though, but perhaps because I am the host. What could cause this and how would I fix it?