Perhaps I should have been a little clearer, I agree it could help where boarding a huge number of pax at once in very frequent traffic is critical, but where services (and passenger numbers) are less intense, not so much so.
As far as I am aware the sole reason for proposing ABDO is to help where boarding/alighting a huge number of pax at once in very frequent traffic is critical, eg Surbiton - Waterloo!
Taking in pre-covid terms the railway between these locations is full in the AM peak. Without introducing ATO and moving block signalling the only ways you can increase capacity are:
- standardising on high performance rolling stock with the same braking and acceleration curve.
- increasing passenger capacity in the same train length
- regularising the braking curve and door release
- opening all doors at the same time.
- countdown tImer linked to live train running to indicate to the driver when doors need to be closed.
All except the last point are achieved through the 701 standardised fleet and ABDO.