I think the important thing about a case like this is not to turn it into a pro/anti fox hunting debate. Anti hunters will inevitably claim that it proves all fox hunting is bad, and pro hunters will defend the fact that they got their dogs off the line as soon as they knew, and were being very responsible.
Personally, I think that the hunters were a bit silly holding a meet near to a railway line, or headed towards a railway line. I know that they will cover a lot of miles, but surely as soon as they are aware they're nearing a railway line or motorway, they should call the dogs back before something like this happens. Of course you'll still get anti hunters complaining of apparent "hunting", but the hunters have stayed well within the law and kept everyone and everything safe.