Callum collaborated with bp pulse to devise a strategic plan for deploying 400 kW DC fast chargers throughout the United States. This initiative involved forecasting electric vehicle charging demands and pinpointing underserved locations lacking adequate charging infrastructure. Furthermore, Callum identified relevant grants and incentives, assisting bp pulse in the application process for securing these funds.

Callum provided commercial and financial advisory services for the Mid-Currituck Bridge project with the North Carolina Department of Transportation. The project, designed to alleviate traffic congestion and serve as a hurricane evacuation route, faced unique challenges due to differing priorities between public and private stakeholders. Callum played a pivotal role in navigating these challenges, developing commercial and financial solutions that aligned with the interests of both parties.

Callum played a crucial role in managing the SCIRF Loan Program for the Texas Department of Transportation, ensuring efficient and effective program administration. He conducted thorough financial and operational due diligence on loan applicants, delivering expert analysis and actionable recommendations.

Callum supported TDOT in preparing for the procurement of their inaugural public-private partnership, the largest public spending initiative in the agency’s history. His role involved ensuring compliance with complex regulatory requirements, facilitating coordination across multiple public agencies, and guiding public outreach efforts to build stakeholder confidence and project support.

During the initial phase of project development, Callum supported the development of the public-private partnership (PPP) case for a dynamic tolling project, comparing it to the traditional design and construct approach. He assisted the client in understanding the commercial and financial differences between the two models and played a key role in engaging the market to gauge interest in this alternative procurement method.

Callum provided ongoing commercial assurance during the operations phase of a public-private partnership. He was responsible for reviewing the operator's compliance with abatements, calculating accurate availability payments, and ensuring transparency and alignment with the project’s financial framework.

Callum served as a subject matter expert for the annual audit of a tier-one contractor, focusing on distressed major projects to assess their financial implications. He reviewed critical project components, including remaining contingency funds, outstanding variation orders, and legal claims, providing insights into realistic cost-to-complete estimates. Key projects under review included the Automated People Mover at LAX, the electrification of CalTrain (San Francisco to San Jose), and the LBJ Freeway widening and reconstruction in Dallas, Texas. Callum’s expertise helped clarify project risks and provided a comprehensive view of their financial health.

In his work with the New York City School Construction Authority, Callum reviewed the processes and controls underpinning a $30 billion (AUD) capital program. His audits provided insights into compliance with key commercial terms and internal controls, ensuring the authority’s activities adhered to industry standards and achieved best-for-project outcomes.

Callum supported the development of the Project Policy and Procedures Manual for the
$5.8 billion AUD redevelopment of Delta Air Lines' terminal at LaGuardia Airport. His responsibilities  included auditing existing controls and ensuring alignment key commercial terms, and construction best practices, contributing to effective governance and project success.

Callum provided mechanical, plumbing, and fire protection design services for a 285,000-square-meter Grade A+ office development in Gurugram, India. This work included the coordination of a dedicated sewage and wastewater treatment plant that serviced the four office buildings.

Callum oversaw routine operations and maintenance conducted by a local O&M contractor at RAAF Base Butterworth in Malaysia on behalf of the Australian Defence Force. His responsibilities included reviewing evidence of completed work to ensure compliance with ADF O&M manuals, as well as reviewing and approving purchases for replacement equipment. The O&M activities primarily focused on the operation of a bulk fuel installation and associated support buildings.

Callum worked as a mechanical engineer on the successful tender package for the Tunnel Stations and Development (TSD) work as part of the Pulse consortium.

Callum worked as a mechanical engineering consultant on a 600-bed prison public-private partnership, including the development of a central energy plant that provided hot water for the complex, as well as all heating and chilled water via ring mains. Additionally, he was responsible for the design of the commercial kitchen area, which included a range of gas-fired equipment and a total of eleven kitchen hoods.