In the UK there is Cranfield University. They do (amongst other things) short courses in gas turbine theory and operations. A colleague of mine has completed this course ...
As mentioned above, the OEM should have a training class for the equipment they produce. All the recip manufacturers I am familiar with have various courses that run 1 week per subject (general engine tech, specific engine model tech, proprietory controls, etc.). You contact the local distributor to sign up and pay for the class. Class schedules are oftentimes on the OEM's website. These classes are not usually going to teach you how to run a plant--there are far too many differences from one site to another. For switchgear, GE offers classes. For engine governing, Woodward offers classes, etc.
You still need site specific training. When we bring in a new operator, we will perform OTJ for up to 3 months (depending upon aptitude and previous experience) before we let that person enjoy a weekend or night shift alone. Many problems seem to occur Friday afternoon through the weekend. The eastern parts house is closed, your outside contractor repair will cost overtime, and the unit will be down an extended period of time waiting for parts or the specialist who has gone to the mountains until Monday.
