Mystery stock on the EB local towards Acton Town?

Coming back from Heathrow just before 6pm today, I saw two unusual sights on the Eastbound local: in South Ealing station, about four or five cars of either 59TS or 62TS, covered in graffiti, one car painted dark green; and a little further towards Acton, a train that was obviously a lot more modern, although it blurred by so fast I didn't really clock anything apart from the big red doors (looked rather '90s, though - BIG doors!). I've not seen anything like that in Northfields before, so I'd guess maybe one or both came from Acton works... anyone able to shed any light?

And while I'm here... the mystery coach under the blue tarpaulin at Northfields seems to have acquired a twin!