At a local refinery, the instrument techs can do electrical work that they feel qualified to do, the union agreed to this.
Many paper mills require you to be two trades and a working knowledge of a third.
One of our customers has a program they call multi-skilled technicians.
All the electricians are really more instrument technicians than they are electricians, as electrical work is contracted out (like running pipe and wire), and the plant electricians are more oriented toward maintaining and debugging the plant equipment.
The mechanics can take some kind of basic electrical or instrumentation classes. The electricians can take one of three mechanical skill sets - welding, hydraulics, or pneumatics I think.
I know one of the electricians got a welding certificate from a local jr college and got $1 something an hour raise for it. Last I had heard he had never actually welded anything in the plant though.
I am not sure if you get any extra pay for more than one skill or not.
From what I can tell the program is popular with the people getting extra pay.
They also have some kind of deal for one line of machines that requires a lot of attention for a mechanic/operator. I think every other machine has an operator that is allegedly cross trained as a mechanic so if a machine in the line goes down, he goes and fixes that machine while the operator on the down machine takes over for him while he works on the down machine. I gather the program has been moderately successful.
Most plants, union or otherwise, I have been in the last 10 or 15 years the instrument techs have wide latitude. They are usually the guys figuring out what is wrong and organizing a fix. A fair number of places the guys with the title of electricians these days are more like instrument techs.