Praise be to Allah the Lord of the Worlds.
It is permissible to work in installing production lines and machines that may be used for producing what is lawful or unlawful; depending on the decision of the producing company. In this case, the unlawful pertains to what the company uses these lines for and there is no direct connection between an engineer`s work and committing the unlawful.
However, if you (Engineer) were acquainted with the fact that the lines and machines which you were asked to install will be used for producing cans of alcoholic drinks, then it isn`t permissible that you install them as doing that is helping others to commit the unlawful, because that company`s business is clearly unlawful. The evidence on this is that the Messenger of Allah (PBUH) cursed ten involved in wine: The one who presses it, the one who has it pressed, its drinker, its carrier, and the one it is carried to, its server, its seller, the consumption of its price, the one who purchases it and the one it was purchased for."{Al-Baihaqhi}. And Allah the Almighty knows best.