The difference is the assistant project manager has to confer with the project manager on major decisions.

A project manager oversees one particular project where a manager deals in general projects

Resident engineer is below project manager. Project Manager first, then Construction Manager, then Resident engineer.

"Project manager" should be capitalized when it is used as a job title or precedes a name, for example, "Project Manager Smith." It should not be capitalized when used generically, such as "the project manager."

The project manager can become:

- A Senior Project Manager
- A PMO
- A Program Manager

Of course after that he can become a CEO.