In message , Lars Elmvang
writes
The service could have been disrupted, and the controller may have
decided to run one, either to get a train back to time or if Olympia
has had a long interval without a train. I've known Circles to be
reformed into Hammersmith's en route before now

If Olympia had a long interval without train there would have had to be
a SERIOUS disruption, since the service is
run with 2 trains running with 15-18 minutes between. (So a complete
round takes 30-36 minutes for that short
stretch)

Sorry to be OT but I was looking at the current District Line timetable
today and wondered exactly where the Triangle depot is...
TIA
--
Kat "A world without string is chaos"