This photo from Mr Lindsay's post is interesting - note the cluster of workers gathered around the switch to the east of the engine.
If the last coach and loco were already off the rails by the time they passed over that switch, any amount of damage could have been done...and then again to the switch that the locomotive came to a stop on.
Those double slip switches have lots of moving parts, and it's understandable that it will take time to get everything fixed and back in adjustment.
It would be interesting to find out where exactly the original derailment happened, and what the dynamcs of that initial event were.
- Paul
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