Given the option of both I'd probably go for LNER (purely based on salary). Northern probably has the more interesting and varied work of the two and you will sign more routes and traction than you will at LNER.
If the salary at Northern was equal to LNER I'd probably opt for Northern based on the following:
- Maximum 4 hours movement from spare (must have 48 hours notice, otherwise 2 hours) on the West it's 3 hours max. LNER is 12 hour movement from spare, in effect you can start the week on an early and end it on a late/night- no thanks!
- You are rarely more than 90 minutes from your home depot at Northern, at LNER the overheads go down on a weekly basis and you're stuck potentially for hours miles from home. Same applies if you fail.
- Daily leave days can be cancelled at LNER, not the case at Northern.
- ECML is largely a boring, featureless route from Newcastle to London. Northern have probably some of the most scenic routes in the UK, Pennines, S&C etc.
- Northern has a better RDW agreement and as you move up the links the start and finish times are less extreme. LNER at Leeds has plenty of 03XX starts, 03XX finishes and quite a few nights.
- Northern (for now) have no door control, I'm pretty sure LNER release the doors which brings its own risks, potentially.
I've seen some of the Northern diagrams at Leeds, I use the messroom when over there so I've looked at their links and diagrams when visiting, they have some intensive jobs, think 10+ trips with short turnarounds and 70+ station stops on the extreme end. Some jobs were much steadier though.
LNER will be less stops and trips but could be more boring potentially. It's quite telling you never see people from LNER/Avanti/XC/TPE coming over to Northern but you do see Northern drivers going the other way, maybe this answers the question of which is best?
If Northern had accepted a deal around 5 or 6 years ago they would be on similar to LNER but it got voted down (I don't know the full terms as I don't work for them).
The salary after tax isn't massively more at LNER as the extra salary will be taxed at the higher rate (something worth thinking about).
Intercity used to be what most would aim for but these days some of the regional operations are paying more, SWR pays more than LNER/Avanti/XC. Then you have TPE/EMR/GWR which aren't really proper Intercity companies and do more semi-fast work- this middle ground probably is where you want to be. Better conditons than the IC operators and better and less intense work than Northern.
Whichever options he chooses and I'm sure he will be thoroughly happy with!