A title is the name of a position within the company heirarchy. "Production Engineer," "Maintenance Engineer," and "Reliability Engineer" are examples of job positions that various kinds of engineers (Chemical Engineers, Mechanical Engineers, etc., by their training) may be hired into.
A role is the part that is played within a specific work process within the company. For example, during a large maintenance outage at a chemical plant, the Maintenance Engineer might be placed in charge of crane lifts, as a safety liaison; a Production Engineer may handle the plant shut-down and start-up logistics by interfacing with outside Utilities people--his role might be called "shutdown coordinator"; and a Reliability Engineer might fill the role of a "gatekeeper" that evaluates unplanned problems found during the planned work, to decide if the additional work should be accomplished during the outage or put off until later.
So a job title speaks to certain abilities and typical tasks based on training and experience, but also speaks to the level of the job within the organization (consider an Assistant Professor versus a Professor) and determines pay grade. But a job role is the application of talents and abilities specific to a situation. A person holding a job title can have different roles in different situations.