I've just joined Colas (in second week) as an OTM (tamper) driver operator.
From the roster for LNW south that I have seen, its varied and you'll be all over the place where your machine is with varying hours depending on whether its light maintenance, or a transit move, or a shift operating. You'll be contracted to 30 weekends a year, which isnt as bad as it sounds as they classify a weekend shift from anything after 1800 on a Friday, to Monday morning. You may just get a friday night, you may get the whole weekend, either way, it will count as a weekend worked whether its one or three shifts worked, if my understanding is correct.
Depending on location, you may lodge at Rugby for the company induction depending how far you are from there, some machine training and most certainly have to lodge at Crewe for 6 weeks for driver rules and regs course.
Salary is good. If the same as OTM tamper, training salary is a smidge over £34k. Once you're operational on the machine as an operator, it will get bumped up quite nicely and will then get bumped up again to circa £50k once you pass out as a train driver and have a route under your belt.