The group is at the centre of investigations into the rail crash at Potters Bar, Hertfordshire, in May in which seven people died.
It is also facing legal action from the victims’ families. In addition chairman Colin Skellett resigned in August after allegations linked to his role as chief executive of Wessex Water.
New chairman Lord McGowan said Mellitt had unparalleled skill and knowledge of the engineering industry, “which is the bedrock of much of our business”. Mellitt stepped down from the IEE last month.
Jarvis has appointed commercial director Rob Johnson to the main board. He joined Jarvis in 1996.