(05 Jan 2017, 5:32 pm)South Tyne Lad Some of the example's provided were delivered before the spare's for every batch was common, Some of them have also now got dedicated spare's of a similar spec, Connection's 4 ( 5324 ) , TEN ( 6084 ) , Drifter ( 5438,9 ) .
Some service's will work with only one, Mostly the ones with a smaller PVR, But a service with a larger PVR is logical to have 2 same spec vehicles in case of a mass breakdown, Some of them you've already hightlighted in your post.
Connections4 - 5324 has been introduced as a dedicated spare for the Connections4, yes, but it wasn't bought new for that purpose and the main reason why it was done was to reduce the amount of different vehicle types at Washington (the three spare Scania L94s have been replaced by two OmniCitys and one Mercedes Citaro).
TEN - 6084 forms part of the PVR of the TEN when not required to cover for a branded vehicle on the Tyne Tees Xpress. It isn't a dedicated spare for the TEN.
Drifter - The combined PVR of the Prince Bishops (20) and Drifter (8) is 28. Two spares for 28 equates to one spare in every 14.
Two spares for a PVR of 9, on a service which has a modern and reliable vehicle allocation, would be very unlikely. If these are heading to Stanley for the Durham Diamond, there would be two spares (5419 and 5451). The combined PVR of the Durham Diamond (9) and Red Kite (14) is 23 - ie one spare in every 11.5 - a spare vehicle percentage which is more in line with the rest of the fleet. At approximately £170,000 a piece, it's difficult to justify ordering a large number of spare buses, when they're not actually required. The Castles Express didn't receive a spare StreetDeck for this reason (approximately £225,000 a piece!)
