No worries
I envisioned it as something like:
21x360 -> 7x 720/1
10x317 -> 5x 720/1
30x321 -> 10x 720/1
47x317 -> 47x 720/5
63x321 -> 42x 720/5
9x321 -> 9x 755/4 (Off the back of the Lowestoft services working through to Liverpool St)
5x153 -> 5x 755/3
9x156 -> 9x 755/3
12x170 -> 12x 755/4
Which leaves an uplift of 3x 755/4. I realise the displacement isn't going to be as like-for-like as that, but it gives some indication of how capacity would be affected in the relevant areas.
With the Train Planner (Rtrd) coming out in me I'd say its a little more complicated than that.
The new units 'should' achieve better availablity than the existing disperate fleet so in respect of the pure EMUs it might look more like this;
21 x 360s = 20 diagrams today = 80 cost peak vehicles (in traffic in the peak) 95% availability
57 x 317s = say 50 diagrams = 200 vehicles 88% availability
103 x 321s = 90 diagrams = 360 vehicles (assumes 4 units not in daily fleet for Renatus works so 90 out of 99) 91% availability
Total = 640 vehicles
22 x 720/10 = 20 diagrams = 200 vehicles (or equal to 240 vehicles equivilent in old money) 91%
89 x 720/5 = 84 diagrams = 420 vehicles (or 504 vehicles) 94%
Total = 744 vehicles (an increase of over 100 vehicles on today's fleet).
Though direct comparisons are complicated by the fact that some 379s today work diagrams that the 720s will work in future and how (or if) the new Stansted and Norwich sets will interwork on 'other' services.
In respect of the bi-modes don't forget that the Pboro-Ips service is due to go 'hourly' with most extended to Colchester (the FA says 13 out of 16 daily) which will need at least 4 rather than 2 diagrams of today and the Norwich - Cambridge service gets extended to Stansted (another 2 diagrams). As 12 car fixed formation will more Stansted Express's call at other stations?
I note that in Railway Gazette's report on the construction of the 720s
http://www.railwaygazette.com/news/...aventra-emus-under-construction-in-derby.html GA are reported as saying;
"Greater Anglia said the exact specification of the interior had not yet been signed off, but the EMUs would have a mix of 3+2 and 2+2 seating. It highlighted that the seats would offer lumbar support, seat-back tables and plug and USB points. The interiors would be ‘light and airy’, with wide inter-car gangways, air-conditioning, underfloor heating, accessible toilets, free wi-fi and information screens indicating empty seats."
Which the comment regarding the specification still not being signed off and a mix of seating is interesting to say the least!