And those 223 replacement carriages are all 23m long, giving a total length of 223*23=5130m. The 214 Pacer carriages were only 16m, so their total length was 214*16=3420m. Arguably a 50% increase in capacity!
Still to enter service are the eight 769s, each comprising 4*20m carriages. That makes a further 32*20=640m, which will increase the total length of replacement diesel trains to 169% of that of the Pacer fleet.
The 150s that have been cascaded in from the Midlands and GW are not included in this calculation. On the other hand, the 153s are presumably still going to leave at some point.