The 5th track proposal was never going to happen.
And yes, the answer for Woking is zero, unless ETCS & ATO comes along.
Yes, that is the problem with Woking. Doing it doesn't give you anything except better regulation and timetabling, and it's a lot of money to spend to make signaller's jobs easier. It has a nice positive BCR because it's easier and cheaper than many of the others on the list, but in terms of actual benefit, it's all a little bit abstract. You're still looking at a round £250m all in.
Hardly anything uses the slows, and if you blocked the WCML there for a month the compensation cost would be immense.
I did mean taking a blockade of the slows and the triangle at Parkside Jn. Disconnect either end from the fasts, take a blockade of either end for a month and build a flyover over the fasts so that it goes up and over the WCML.
Now, it's not really necessary, but it's one that as time goes on, with a new station at Golbourne and the new terminal at Parkside, starts to look attractive just to allow better separation of the different flows.
My vote goes to Harpenden and West Hampstead South, albeit the latter is nigh on impossible. These two bookend the stretch of line that has the most reactionary delay on the network
For me, the one I could never get over was Camden Road and Gospel Oak Jns. Honestly, if I could, I'd grade separate out the entirety of the NLL, and every single connecting chord in North London. Unfortunately, that would probably cost about as much as HS2, and this thread was about which ones were possible, as much as which ones were needed.