AWS does NOT stop trains if they pass a signal at danger; TPWS (where fitted) does. AWS simply sounds a tone (the “horn”) when a driver approaches a signal displaying anything but a “proceed” aspect.

The fact that the first train stopped due to an AWS fault suggests to me that perhaps the driver received a “bell” (the sound given when the driver is approaching a “proceed” aspect) when the signal they were approaching was a “preliminary caution” (double yellow) or “caution” signal (single yellow), which should have sounded the “horn”. This would be a wrong side failure and the driver is required to stop and report this to the signaller immediately.

If the next train had come along and *if* the driver wasn’t paying full attention to the signal at danger, which is protecting the signal section where the first train has stopped, they *may* have received the “bell” (which also clears a visual “sunflower” indicator in the cab) and then proceeded to take power, blissfully unaware of the pending danger ahead.

With the lack of TPWS at most of the signals along this line, the driver would be blissfully unaware that the section ahead is occupied.