Great Western Coffee Shop

From journeycheck https://www.journeycheck.com/greatwesternrailway/
08:15 Penzance to London Paddington due 13:29
08:15 Penzance to London Paddington due 13:29 will be started from Plymouth.
It will no longer call at Penzance, St Erth, Camborne, Redruth, Truro, St Austell, Par, Bodmin Parkway and Liskeard.
This is due to a derailment within the depot.
Further Information

If you hold a valid single, return, or weekly ticket, you will be able to claim compensation for delays of 15 minutes or more. Please keep your ticket and visit GWR.com/DelayRepay
Last Updated:26/02/2021 02:18

Not sure what that means.
The only cancellation is the 08h15, all other departures from the depot and Penzance seem to have run on time.
Assuming this one derailed but it didn't affect any other lines.

08:15 Penzance to London Paddington due 13:29 will be started from Plymouth.
It will no longer call at Penzance, St Erth, Camborne, Redruth, Truro, St Austell, Par, Bodmin Parkway and Liskeard.
This is due to a derailment within the depot.

This happened this morning (26/2/21)

Does anybody know what stock derailed?

_{[Duplicate topics merged - RS]}

It was a Class 08 pilot shunter and a seating carriage from the sleeper - this one to be precise:  https://commons.wikimedia.org/wiki/File:Long_Rock_Sidings_-_GWR_Mark_3_TSO_12100.JPG