Sheffield tram incident?

[D365]

I was out walking in the Castle Square area, about an hour ago. There were two trams at Castle Square station, one in each platform, with "Not In Service" showing on the exterior displays. A tram-train was waiting behind the westbound tram, still showing "Cathedral" on the exterior displays, but with the hazard lights blinking. Any information on what has happened here?

 

[ALEMASTER]

Looking back to that day on Twitter there was no service disruption around that time although there had been a cancellation on the Purple route in the morning with a tram returning to depot out of service from Herdings Park, around 8:30am. It is likely that the trams in the platform were being swapped over for maintenance requirements or they were simply out on test following some work in the depot.

The Tram Train would have been sat awaiting the platform, it is normal for the hazard lights to be activated if the tram has remained stationary for any amount of time.