I've watched it again and I can definitely see something that looks like a person.
I haven't felt this confused since I was in the hall of mirrors.
Damaging the FPI, giving a false signal? Or damaging something related to the pointwork? Is there anything that could be damaged at that moment relating to the movement of those particular points? There doesn't seem to be a strike visible on the video, for instance, so it would have to be remote stuff, unless it was damaged earlier in such a way that caused the points to swing back and forth?
Lots of speculation on here.
I worked on this tramway for many years, and the way these points work has not changed.
These are spring points.
They have no motor.
The blades cannot move unless a tram passes over them northbound which pushes the blades across and then they spring back.
They always lay points left when approached from Hucknall so the tram goes into the southbound platform.
The FPI has two states when powered , if the points have swung back correctly it will show points left, if not it will show a horizontal bar.
This is acted on the same as a stop signal, the driver should stop, get out, work the points with a points bar and attempt to get points left.
If not, they contact control.
There is no need for facing point locks, the FPI is always visible from a suitable distance for the driver to see it and act accordingly.
There are I think three possibilities….
1) The driver has failed to notice the FPI on a bar and passed over points which have not swung back. As the front bogie passes over this has caused them to go back to the correct points left status, causing the centre bogie to take the left route and derail as the tram tries to follow the front bogie.
2) A “Swiss Cheese” moment, the points have not gone back following a northbound tram, a lightning strike on the point controller causing the FPI to go out, and the driver not following their training which is to treat a blank signal or FPI as a stop signal and act accordingly
3) A wrong side failure, despite the points not having swung back they have been detected as correctly set, so the driver has rightly assumed the tram will take the correct route.
The RAIB report will I’m sure reveal what happened.
FPI = FACING POINT INDICATOR.
Shows the driver how a set of points they are approaching on a diverging route are set ahead of them.
Hope this clarifies things!