Mainstream Commercial Diving

Executive Team


John Bull, Business Unit Leader

With a background in operations, logistics, and organizational strategy, John has led the Drummac organization since 2018. John is a graduate of Kent State University with a Bachelor's Degree in Business Management and has more than a decade of experience in leadership across several industries and disciplines. 


David Livorsi, Operations Manager

David is responsible for managing all operations, personnel, and client matters within Drummac's core business line, and has been a key operational leader since 2012. David is a graduate of DeVry University with a Bachelor's Degree in Project Management. Having served in the U.S. Navy as a Gas Turbine System Technician, David's mechanical background and management style are largely influenced by his achievements while in the service. 


George Frye, CMO, Mobile Mechanical Services (MMS)

George has over twenty-five (25) years of mechanical rolling stock experience in passenger rail. George oversees and manages mechanical operations and training for Drummac's Mobile Mechanical Services (MMS) business. His previous railroad experience includes many years with Amtrak in Washington, D.C. as machinist, electrician, car repairman, and locomotive dispatch supervisor.