The new DMIs at Harrow on the hill P5/6 also display confusing info sometimes. I was hypothesising that the DMIs were collaging information from a couple of different sources and sometimes displaying the same train twice (with slightly different times). I was thinking that in HoH's case the sources would be the Uxbridge branch, the other lines, and the signaller, or possibly other prediction software and the signaller. Where does the information that feeds these new DMIs come from?
I might open another thread to discuss what the P5/6 Harrow DMIs actually mean - some of their predictions are clear as mud (and still do not say which platform is departing first)
I don't really know the top end of the Met well enough, but could it be anything to do with the fast and slow lines? The train which is currently nearer is on the slow line, and the train which is currently a bit further south is on the fast line and will get there first?
As its a manually controlled frame and the signaller may not be able to follow the timetable to the extent of the correct platform for what ever reason that may be the system for the TD is not able until the route is selected know what platform the train is coming in