Bouchez follows research director Anthony Waithe and sales director Steve Atkinson out of Titan's front door - both left this month, with Waithe leaving to take up the same role at CBS.
Bouchez, who was part of the original senior staff line-up at Maiden when it was acquired by Titan a year ago, will be responsible for all of CBS's London rail network.
Don Allman, chief executive of Titan Worldwide, said: "Since the acquisition of Maiden, Titan has gone from strength to strength. We have made over 100 hires, increasing sales 13% year on year, and we look forward to future growth."