Tube Drivers - are they overpaid?

The revelation that tube drivers have secured packages worth in excess of £60k has surprised many.  Everyone goes on about how that is more than senior managers and senior teachers etc etc.  But I think that it is a very difficult job to do.  Its lonely, its dark, its repetitive and you do need some particular skills such as following complex signals that few people have.  Oh, and you really cant make a mistake as that would be dangerous.  Working in a tunnel all day needs to be rewarded.  Having said that monopoly power helps in that they can flex their muscles to get a good deal.