I too have wanted to know that for a long time !
- Working it out can be very difficult for an enthusiast because of various complications, and in a place like Worcester where services or groups of services are "inter-worked" and vehicles swopped off and on, - - the only useful/ valid PVR figure MAY be for the whole WR network (?)
Regarding the new network,
I did a "mini-survey" of the 144/A on Friday, between c.08.55 and c.13.30 (school-day timetable).
I "got lucky" in-that most of the vehicles returning southbound to Crowngate on the 144 and 144A, - subsequently re-issued northwards onto the 144 and 144A -
IE: mainly the same vehicles on each service - NOT interworked.
(This makes it easier to try and work-out "what the heck" is going-on, and will allow Euro 6 vehicles to be allocated to the 144 for Birmingham, and NON-Euro6 vehicles to the 144A.
What I saw was :-
9 different Enviro 300s allocated throughout the period - (67651/53/55/56/57/61/62/63/99).
Plus:
1 StreetLite (47520);
1 DD arriving Crowngate on a short 144, but then "off and away" - I believe this would have been from Bromsgrove (and previously on the S45).
1 DD arriving on a short 144 at Crowngate, probably from Droitwich, and possibly having previously been on one of S1- S4 - -
( - In recent years, one or two DDs off the S1-S4 have progressed southwards along the London Road, - then east and north via "Sixways" to enter the southbound 144 at Droitwich or Bromsgrove).
- This DD then remained on the 144A throughout my survey period.
1 DD arriving on the 144A at Crowngate (presumably having originated on the S1-S4 as per above); - - this was then "sent away", and a further Enviro 300 (67664) was put onto the 144A ( - but not necessarily at the same time )
SO ! - I would say that the PVR for the 144/A could be 13 vehicles.
(There is a chance that it MIGHT be 14, because 67659 was also in use on the 144 around the start and finish of my "survey", but I think it may have been removed just before the start of my survey period, and put back on just after - ??? )
IF I was to do a similar "survey" covering a different part of the day, I would be very surprised if the 144/A needed more than 13 vehicles !
When WR gets it's 12 green Volvo single deckers, I see no reason why
the 3 double-deckers shouldn't continue to be used as above/currently.
Note that there were NO double-deckers to or from Brum, during my survey on Friday, BUT there were at least two, (NON-Euro 6), on Saturday on the 144.