Ok guys. Now look here...
Whatever your side on this story, we can all agree 4 things:
1. Whether they were 'right' or 'wrong' to sack said person - this has been a PR disaster for SWT! - they should be sacking their PR manager first of all!
2. Whether said person was 'right' or 'wrong' for picking up the shopping trolley - sacking them in this way, just sends out all the wrong signals - maybe the 1-dimensional minds amongst this forum cannot see beyond simple rules and regulations - but you're ignoring the human element in all of this, and public opinion - these two things have a huge and serious bearing on 'unfair dismissal' hearings (even if in you perfect utopian worlds they shouldn't do).
3. Past actions of being a 'trouble maker' may logically make someone more deserving of a sacking in your opinions, but this is not the way the courts will view it: they will look at the incident alone, and any extraneous stuff that is referred to will be ignored. They're not interested in what this bloke did before the shopping trolley incident - they're only interested in what happened that day. I can quite easily see a judge concluding here that the employer (SWT) was negligent here for not putting in place a clear emergency plan for 'what to do' in the case of an obstacle falling onto the track, and thereby placing an employee in a unclear situation of dilemma. A barrister could quite easily build a case to support this around the 1898 case where no wrong doing was found on the part of the employees, and instead changes had to be made to the design of railway platforms.
4. The fact that this is now going the distance with parliament, MPs, the press, petitions, etc. should tell you something: whether you think SWT were essentially 'right' or 'wrong' in their actions is kind of irrelevant now - this has now got serious! And so dismissing it like it is some sort of localised joke is trivialising something that is already far bigger than you realise. This story is not going to go away - and I think that until this guy is exonerated - you will get a strengthening of his public support - SWT have turned him into a martyr through their mishandling of the situation. And whether he was in the 'right' or the 'wrong' in the first instance is now kind of irrelevant...