McIntosh is currently Network Rail Project Director for European Train Control System and Traffic Management.
He will now be responsible for overseeing the £2.3bn upgrade of the existing rail network for Crossrail services.
Robbie Burns, Network Rail Regional Director, Western and Wales said: “Rob McIntosh has extensive project management experience in the delivery of railway system projects including train control, infrastructure and stations.
“Rob will have a key role to play in overseeing the multi-billion upgrade of the existing rail network for Crossrail.”