I disagree about the dispatcher, Carl. Dispatchers give permission by stop signals all the time without knowing the cause of the circuit being down or failing to clear. That's what restricted speed is all about.
Not knowing, I would think that there are some employee timetable instructions that cover the operation of the bridge and what to do if a signal is not received.
I have to say that I obtained permission by more than one stop signal that no one knew what the cause was, sometimes it would be something we would find, like a broken rail, but frequently, it was nothing we found, and I don't think they were all operating tests. The bridge, I admit, is a special circumstance, but I'm guessing the dispatcher followed procedure. I hope the conductor did.