1. What's the purpose of the connection between ELR and Metrolink? For whose benefit? Metrolink to National Network via ELR and Castleton?
2. Is there another connection between Metrolink and anything else? I think the connnection east of Victoria was lifted some time ago.
3. Surely the purpose of Trap/Catch points is to prevent a runaway from fouling the running lines?
Engineering trains have used the ELR link to access Metrolink track from time to time, although this would only be under possession and full-height locomotives don't fit.
There is another connection at Altrincham and the Oldham Rochdale line included connections at Dean Lane refuse terminal and at the Rochdale reversing siding but I think the latter was never connected. These were all similarly intended for engineering access.
It appears from the post above that ELR now considers the trap point needs to be relocated, but no doubt RAIB will have a view on that. There have been accidents in the past when a train is derailed on traps but ends up foul of the line they should have been protecting.
However, commenting in general rather than on this specific incident, depending on gradients an unbraked train rolling out of a siding with no traps could a long distance on the main line and cause a severe accident.