I know they are already used BiDi but they will have to be used BiDi a lot more with the new layout. I was under the impression that generally they used the lines as Up and Down lines and BiDi was only used when it had to be like P0 or when there is slight disruption to try and get services regulated quicker.
Yes and no. Whilst it’s very true that under the current setup most services use their rightful direction lines, there’s a substantial minority of routes that require this not to be the case.
~ Anything arriving from the up fast going into platforms 6 to 9 will need to go via line B
~ Anything departing from platform 0 will need to go via line A
~ Anything departing from platforms 4 to 7 heading for the down slow will need to go via line C
There are of course some alternatives, for example in the first case above the train may instead cross to the up slow at Holloway and run via line C, or further cross to line B at Belle Isle.
The current layout allows some wonderful flexibility by making use of the crossovers at Belle Isle and/or Holloway, and it’s possible to pull off some very skilful parallel moves if the signaller is on the money. Time will tell if the new layout will work as well, being cynical one can’t help but think that a major motivator is saving costs by rationalising the number of points, and particular some of the more complex ones in the immediate throat.