Astradome..
there is legislation that covers this, and you working in the Rail Industry are probably aware of it. That offence, like most is an individual repsonsibility. No one is forced to drink, no one is forced to go to work after they have been drinking. It may well be that someone goes to work not knowing they are over a limit for the amount of alcohol in thier blood, but ignorance is not a defence, it may however be mitigation. Your employer is not responsible if you steal something, nor if you assault someone, why should they be if you have had too much to drink? As you know the driver of a train will still be prosecuted if he is involved in something while having had drugs or too much to drink. The company wont be.
So there has been codification (if that word exists) and there is legislation. There has been enough publicity about this new act, certainly where I work.
The Goverment, for whatever reason have decided that that legislation does require the attendence of a police officer to investigate it. But as with anything, if no one calls the police, then there is nothing to stop it being dealt with another way. It seems, if the information given is correct, that thats whats happened here. Whether that was the right way is other matter.
Sadly nothing prevents this sort of situation arrising, drivers of trains still turn up having had a drink, bus drivers turn up over the drink drive limits, so do police officers......