If only it was that simple. It is perfectly legitimate to let someone cross with a train accepted or even already in section, if there's enough time for them to do so safely. It is only for large/slow vehicles requiring signal protection that the block indicator becomes rather more definitive.The telephones on all these UWC could be routed to a single handset & if the Up/down block instruments show Line Clear or Train in Section, as that phone rings a big sign lights up saying "Reminder, Block Occupied Say NO". A little ESP32 & a cheap LED sign from Temu would do the job for £30, although Westinghouse or Siemens will probably charge £30,000 for it.
It seems that the main job of the signaller in this box is to answer that phone. They aren't working a complex junction or regulating a busy commuter line, they are accepting a train from up the line, setting their instruments & signals & passing it on to the next box. Due to fatigue, distraction or being told by a superior to ignore the rules they forgot they had accepted a train & that it was in section when answering that one call.
The ones that I used to supervise, they still had the repeater instruments but were not allowed to rely on them – they just used them as a guide to know when to phone and when not to bother. We still provided signal protection directly in one direction and via the block in the other.How do they handle unusually large or slow vehicles?
Do they have their own protecting signals, are they slotted with the controlling box's signals, or is there no signal protection at all, barring phoning the controlling box and asking for a block?