Not sure what this airline is running to

That looks like a fan control. I haven't seen one of that type in years. At one time there would be two one for the fan and one for the shutters.

 

Thanks for your information as it is often impressive. Now maybe you are telling your age. Must live pretty far North as the only air controlled shutters I have seen in 20 years are on Blue to the left.
To the point those manual valves were very dependable and simple. Just figure out how to make it work.

 

Those air valves were very reliable. After years of use they would leak air out the exhaust. I replaced a few.
I'm in my 45th fifth year as a mechanic. About 80% of my career has been working on trucks. I spent 24 years at a dealership and received a lot of training.
I am 65 this October and I can comfortably retire but I may keep working part time for a bit longer.