Solved

Up skills mechanics (pit stop)

Where I can find my engineers and mechanics? I have pit time nearly 4,5 second and I'm disgusting from this.

On forum I read that I need to up skills my engineer and mechanics, but, anyway, I can't find where I can train this proffesionals...

In the older version of the game before it was tweaked to be mobile app friendly, there was a way to train your mechanics up to "level 20". They are now unable to be trained and I don't remember if their skill level is related to the old system of levels.

As a warning to anybody reading the forums, the overwhelming majority of posts over 9 months old may discuss expired information. The game is completely different right now to what it was before the update in August.