St Albans to Watford etc - there is a fairly clear alternative route from Park street in the direction of the city station.
I’m afraid it’s not clear at all. Buildings in the way (some listed) or flood plain. Take your pick!
getting the time down to just under 15 minutes - can that really be sufficient to run a 30 minute service - no rest time, no resilience?
The time needs to average 12 minutes, with 3 minute turnarounds.
Its 16 minutes now (17 in the middle of the day, with longer dwells).
DCO will take out 1.5 mins (by making all stops 30 sec).
Improving linespeed (including approach speed at the Abbey) could save 1.25mins
That brings the standard end to end all stops time down to 12.75mins. Add 3 mins for the turn round, and 2 return trips an hour needs 65 mins. Therefore we need to find 5 minutes from 4 trips.
Taking out each stop will save 75 sec. 4 stops is 5 mins. Therefore we need to lose 4 stops (total) from 4 services in the hour. Options:
1) close a station (very unlikely!)
2) skip stop any one of the stops from every train (varying the skip, and not Watford N)
3) skip stop two from every other service (but not both of Park St and How Wood in the same service, nor Watford N in any) making a ‘slow’ and ‘not quite as slow’ service each hour.
This is all my fag packet estimates, no official work has been done on this.