I think they can, as long as the relationship is clear and the roles and responsibilities are defined from day one. Management above the project must buy-in to the concept of having two project managers and must agree to the defined R&R.
I am working on a large project. Within 6 months, working on the initial concepts, designs and plans in the initiation stage of the project, I realized that there was too much coordination, communication, vendor management, internal team management, user management and reporting required for a single Project Manager. I needed help and I was not afraid to ask.
We now have two Project Managers on the project and it is working really well. I am an easy person to build a relationship with. I will trust and accept any person, until they cross me or my team. The new Project Manager has a wealth of experience and is a great asset to the Project.
People within the Project Management Department often comment that there are two Project Managers working on the single project, but I see no issue with it. Slowly, the colperets are coming around to understanding that the Project has a requirement for two Project Managers to work in tandem together to be able to achieve the final delivery in the manner that the corporation requires.
Usually a Programme will have many Project Managers, but usually a project will only have one, however, due to the size and structure of the project, this project warrants the use of two project managers.
Defining the roles and responsibilities between us was an important "first day" task. Over the past year, I had built relationships with vendors, internal technical team, management and the business. The one part (and important part) of the Project Management I failed to keep on top of was the reporting. My direction as a Project Manager is to "get the job done", so I did. I covered all bases, ensuring that we had the best options, decided on the best solutions, worked with the best people and built relationships to ensure we obtained the best deals for the company I am working for. This was all to the detriment of the reporting side and the management of the stakeholders. A bad mistake.
The other Project Manager will take care of all of the governance and the management reporting side of the project, leaving me to run with the vendor engagement and the management of the technical teams to deliver the product. I am a Project Manager that focuses on the delivery rather than the Project status updates and the "Project Management" side.
Have you ever worked on a single project, with another project manager? What was your experience, what worked and what didn't?