What is the ruling on taking a commission from a contractor for work done through an engineer who requests a commission and works for the same company with which the contractor will contract?

There is no harm in seeking a contractor for the company in exchange for a commission taken from the contractor if he agrees, as this is a permissible brokerage. As for the engineer who desires a commission for himself, if his search for the contractor is part of his work for the company, then he is not allowed to request a commission except with the company's permission. However, if it is not part of his official duties, and he directs the contractor to the company outside of his working hours and requests a commission, then there is no harm in that.