This is all very sad. I don't travel to work by train because my office is right by what is also my closest station so I walk to work, though now working from home for the foreseeable future. Though I do sometimes use the train for business purposes (to get to the office in London or something else in London) it's not that often. Most of my travel is leisure and it's sad to read that it likely means I won't be allowed to travel by train (or bus) for sometime.
I do have a car so at least if we are allowed to travel for non essential purposes I'll be able to get about, but seemingly not by public transport. Central London for example would essentially be off limits, too far to walk or cycle and I'd not want to drive there, even with less traffic about.
As to the safe operation of trains, is there actually that much that needs to change from a staff point of view? I appreciate keeping passengers the required distance apart is hard, but not sure that is actually the role of rail staff? They can only advise, surely?
The driver is already isolated from the public (largely) in a cab. I would hope there is a wash down of the controls and other surfaces at the end of each shift and when drivers swap, but you'd hope that is already happening anyway. I suppose there is a problem where trains need to reverse en-route and the guard and driver need to swap ends (I'm thinking some branch lines like Gunnislake, Marlow, Esk Valley etc) especially if they cannot do so on a station platform.
THen guards. They are not on all services anyway but where they are on many types of stock I believe the doors can be operated from the unused cab at the back of the train. So again on a lot of routes the guard can safely work in a part of the train segregated from the public if they are not required to check tickets etc (which I believe is the case at the moment .... correct me if I'm wrong).
So perhaps that only leaves types of trains where the doors can only be controlled from within the passenger saloon where there is a problem. In that case would it be possible to partition off the part of the train between the drivers cab and the next passenger door down? So perhaps you lose the front 1/3 of the train for passenger use and the guard can work the doors from there? I know on some types of trains (e.g. SWR do it on the 159s) the door behind the currently used drivers can be locked so it doesn't open from outside. Though stopping passengers trying to get in through that door anyway might be a problem....