I have noticed the irregular frequencies, and irregular destinations between the alternating services in the core, which given the amount of slack in the timetables is surprising. The western side does seem to have the worst of it, at Slough eastbound a long interval was followed by a stone train running, at speed, right in the next Eliz train path. One wonders what the regulation approach here is. Maidenhead to Ealing is 19 miles, the Eliz trains are timetabled for 32 minutes, that's 36mph overall, the stone trains run faster than that so should not really get in the way. Notably some spirited running (not skipping stops) made up quite an amount of the delay, but was then all lost again by a 6 minute stand at Westbourne Park.