Looking for a manga that has to do with civil engineers' migrant workers or Mechanics
 

This topic cause A good percentage of my family is a Mechanic or in the Military(military engineers count too) & plus I dont think anybody has done it or I'm unconsious of it's precence...

Hmmm... This is a tough one to find... I'm not sure there is a manga like that, or I'm not aware of it.

Salary man Kintaro?

Later in the episodes it comes to a tunnel that's collapsing, workers, construction, ect.

the main character works for a construction company, which is what the entire series is based of off.

you might like it.

Hmm.... Towards the end of Honey And Clover there is that epic bike ride that is interrupted by a stay with construction workers.