Coming back home the other day, there was some kind of power issue at Southall that meant that the rear four coaches had to be locked out of use (the PIS display opposite me (in the fifth carriage) wasn't working, but it was perfectly light outside so I don't know what the reason was). Driver made three announcements, with the result that only a few people tried the doors at the back before running forward (
), and we set off five minutes late. At Hayes, however, the driver had either forgotten to reset the door equipment or the system hadn't reset, because the back four coaches remained locked out of use, which necessitated another two-minute delay as everyone rushed forward!
The service was getting back to normal after an earlier delay though (GWR had several services delayed significantly, and my train into Paddington was five minutes late), so there were some hold-ups behind late-running services in front.
The very integration of the service is its downfall on the reliability front though - it inherits the delays of both the GWML and GEML and even a minor delay is exacerbated with a 24tph service!