If those staff are paid by the hour, then they will not be paid when others are working instead of them and if they are not working overtime they will ultimately be paid a lower hourly rate to begin with. With such a large workforce many of them would be at home on days off instead of everyone sitting spare at the depot all day.Perhaps but it also has to pay those staff, hire managers to manage and assess them, provide adequate mess facilities for those sitting spare, make sure they have appropriate equipment, uniform etc.
It's the same reason Sundays outside arrangements persist in so many places. Companies would much rather pay an enhanced rate to get a reduced number of crew in vs having the entire depot sat spare on full pay when engineering work happens.
There should not be a reduced service on Sundays in the 21st century just because a Roman general executed a man known as Jesus Christ 1988 years ago and there wouldn’t need to be if staff had regular days off on other days of the week, which by definition needs a larger workforce. Has anyone ever considered bringing rail replacement buses in house and allowing train drivers to drive them during engineering works?
Clearly previous traction knowledge should take precedence, especially if it is for a traction type common to both TOCs, because otherwise the new TOC is throwing away the skills which it needs to run HSTs anyway which are already in short supply.Possibly a result of the link that they will start in? Moving to a different TOC voluntarily results in a loss of seniority. If the link joined for new entrants at the new TOC doesn't have HST work then this is not surprising. Previous traction knowledge doesn't override the agreed linking arrangements or terms and conditions at the new TOC.
If a driver was transferring voluntarily from the InterCity Great Western division of BR to it’s InterCity CrossCountry division would be have lost knowledge of HSTs, or is this simply irrelevant because a driver at Laira depot would have routinely driven both the GW and the XC HSTs within a given area?