You get booked off sick for as long as you need (or, at least, as long as your GP keeps signing those doctors notes). There is certainly no pressure for you to come back, because you'd be next to useless if you kept going to pieces every time you thought someone was getting a wee bit close to the platform edge. You are also offered counselling through BUPA, whose counsellors are experienced with dealing with railway staff, though this is at the driver's discretion. When you do feel ready to come back, there is a "staged" return to work tailored to suit your needs. This can include riding PASS over the affected line and riding in the driving cab, but you will always be accompanied by a manager on your first driving turn over the route to make sure you're OK and to pass you as fit to return to work. You should also be accompanied by your manager and a union rep when you attend the inquest.
On the monetary side, drivers suffering a "fatal" are entitled to claim compensation from the Criminal Injuries Compensation Board/Authority, which is generally £1000. On the downside, you do have to demonstrate genuine harm caused and have been off for a certain amount of time (generally not less than 6 weeks). I didn't go for the compensation myself because I knew I wasn't off for long enough and didn't feel that bad.
I've no complaints whatsoever about the treatment I had from the company, my managers or my colleagues after my "fatal".
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