That's a pity. What is the cause of delays on this section - unreliable
rolling stock,signalling block length, track capacity constraints,
competition with competing cross London freight trains etc? Or is this
a repeat of "Operation Princess" - building in too much interdependent
complexity?

I think a case of all of the above - if it were just one issue, it
could probably be solved. I think the rolling stock is basically OK
though, I rarely hear fo trains being cancelled because of "train
failure" or such like.

There is an element of too much complexity: although I don't think
that's a drastic problem.

The annoying thing is that despite advertising 4tph, what in reality
happens during the AM peak is that only 3 tph run with steadily
increasing delays from 7:30am onwards. It seems that there is a big
gap between ambition and reality on the line: often if the train is
indicated as running on time, it runs 5-10 mins late - I wonder if this
data is being used to compile the hopelessly optimistic performance
rates on the line?