At a guess there guys I would say it isn't that old.
I also work for a Power Company as does Ray and we have a turn-around time (locally) of 3-5 years before the transformers (of any size) are replaced, drained, stripped down, re-wound and re-commissioned.
Electrical apprentices here at Electricity Ashburton certainly do thier time in the Transformer shop.
Only way to learn I say, look at how the tranny in front of you is being wound.
