I'm relocated to London for my previous career and ended up becoming a train driver after I moved down. There are a few things which you might want to know.
Firstly, London can be quite a noisy city at night, much of it due to traffic, you'll most likely get used to it (I can sleep through an ambulance on a call going past my house).
Secondly, the quality of property and landlords varies quite a bit, I do know of a houseshare organisation of which the member landlords are encouraged to meet certain standards which I believe are above the legal minimum, happy to PM you the details if you like.
Thirdly, if you're based at Euston, you may want to think about how you're going to get there. I don't know about staff parking, that's something you'd need to ask your TOC about.
Lastly, if you are in a houseshare, you are quite possibly going to get at least one pillock in the house at any one time. I've been in a houseshare for a few years and whilst there have been some really good housemates, very little of that time has been true idiot-free living.
Edited to add:
Try and avoid couples, we allowed one lad to bring his girlfriend into the house for six months and he went from being generally decent to complete prat in next to no time. Also, if there are any weed smokers, make sure they keep it outside, it's surprisingly common even amongst those in the professions.