Let's say NR and DfT wanted to increase the capacity for electrification work, how realistic is that in what timetable? I see there are now various 'rail academies' starting, presumably aimed at training more engineers - would one solution be to boost those in order to get more resource available?
Also, and maybe relevant to TP electrification, I have understood that from an engineering perspective having longer possesions is more effeicent for fairly obvious reasons. I wonder if having a look to say full weekend possesions on parts of the TP line (with Calder valley open and services diverted / strengthened for example) would allow TP electrification to proceed quicker, cheaper and with a more optimal use of those resources. Maybe that is something that RailNorth may be better able to agree than DfT as they are 'more representative' of the local population?
It depends on what single track mileages Network Rail, the DfT and HM Treasury can agree upon and what can be afforded. Electrification is a one time project, unlike renewals, and these are skilled careers with a fair bit of time and money needing to be invested, it would be wise to have a fairly rigid plan of action that can be agreed upon and stuck to.
In an ideal world, you would commit to 100% electrification over the average career span, around 45 years. You recruit school leavers into as many roles as possible and train them up for a job they will retire from in 2055-2060, when we finish wiring to Wick or Mallaig or something, with lower level on-going recruitment and training to meet natural wastage and to provide maintenance staff for post completion repairs and renewals work.
The current capacity could be sufficient (just) if that's the baseline levels that would be utilised in CP6 onwards, if you want to ramp up electrification, then now is the time to be training and recruiting, given there are current schemes that apprentices can be taken to and shown around, and gradually introduced to. Training when there isn't work on-going is much more difficult, and recruitment is increasingly difficult now with falling unemployment - people want a modicum of job security, which you don't get with projects based on a 5 year cycle of investment, and one where there's only one customer to boot.
Re the possession question - absolutely, the longer the possession, the more time can be spent on site actually doing work, and the easier it is to do the work. A weekend closure with diversions would be bliss for the GWML and it would make the TP scheme easier - 54 hours gives you a good 50 to 52 hours of on-site time, with 2 - 4 hours to get train and plant on and off site, you'll still have 2 to 4 hours of getting trains and plant on and off site with overnight possessions, but you only start with 7 to 8 hours, about half of which is wasted.
Longer possessions could more realistically make use of proper locomotives and rolling stock too, no more of these preposterous Windhoff units which take far too long to move around. The Carillion setup in Scotland works really well - Movax piling rig, converted container flats for piles, and a pair of Class 66 locomotives to move the lot around. Longer possessions also need longer trains, which can easily be provided with a top and tail locomotive configuration - if you use a fixed formation HOPS style train, no matter how long the possession, when it's empty it needs to go back to base for re-loading.