Yes appreciate won't always have driver for that ECS, but sometimes surely they will do. Just seems odd to short form an 8 car 10+ trains diagram to 4 car all day, rather than 12 car to 8 car 2 train diagram. Don't short forms get counted against reliability stats?
On the wider question of whether GA could run more 12 car trains on West Anglia. It's difficult. They would need more trains. Now there are 9 class 317 units at Ilford off lease, in theory they could be re-leased relatively quickly, assuming price could be agreed with owner. However DfT only 2 years ago awarded franchise on basis that Abellio would cancel/not renew leases on those units, and franchise premium/subsidy calculated accordingly. DfT could amend franchise specification but if franchisee has to lease more trains = more subsidy/less premium so they prob won't want to.
Even if had the trains, if you don't run 12 cars on Stansteds, operationally it is hard to serve Brox, Sawb, Stan M with 12 car Camb services as all the semi fast Camb train diagrams also involve Camb stoppers and Hertford East services, and those trains stop at various stations that only accommodate 8 cars.
So going back to the original q as to why Sawb and Stan M platforms were extended, seems that after decided that Stansteds didn't need 12 cars, and under-utilised 379s would be used on the peak additional fast trains from Camb, turns out no need at all for the longer platforms, not for next few years anyway.
Could be proved wrong of course. Been reports that Abellio has been awarded new 2 yr franchise to Oct 16, but no formal announcement. Perhaps we will find out they have agreed a new round of improvements inc getting those 317s back and more 12 car trains, but I doubt it somehow.
On the wider question of whether GA could run more 12 car trains on West Anglia. It's difficult. They would need more trains. Now there are 9 class 317 units at Ilford off lease, in theory they could be re-leased relatively quickly, assuming price could be agreed with owner. However DfT only 2 years ago awarded franchise on basis that Abellio would cancel/not renew leases on those units, and franchise premium/subsidy calculated accordingly. DfT could amend franchise specification but if franchisee has to lease more trains = more subsidy/less premium so they prob won't want to.
Even if had the trains, if you don't run 12 cars on Stansteds, operationally it is hard to serve Brox, Sawb, Stan M with 12 car Camb services as all the semi fast Camb train diagrams also involve Camb stoppers and Hertford East services, and those trains stop at various stations that only accommodate 8 cars.
So going back to the original q as to why Sawb and Stan M platforms were extended, seems that after decided that Stansteds didn't need 12 cars, and under-utilised 379s would be used on the peak additional fast trains from Camb, turns out no need at all for the longer platforms, not for next few years anyway.
Could be proved wrong of course. Been reports that Abellio has been awarded new 2 yr franchise to Oct 16, but no formal announcement. Perhaps we will find out they have agreed a new round of improvements inc getting those 317s back and more 12 car trains, but I doubt it somehow.