The High Luminosity Large Hadron Collider (HL-LHC) project seeks to significantly enhance the performance of the LHC to deliver ten times more data to the LHC Experiments. The project relies on cutting-edge systems and technologies deployed in the new facilities constructed to the HL-LHC requisites and replacing large existing equipment and systems in the LHC tunnel. The project complexity lies in the production and installation of innovative systems with strong interdependencies. A methodological schedule management approach is essential to ensure timely equipment delivery, anticipate potential risks and implement mitigation actions. This paper describes the schedule management aspects of the HL-LHC project, providing a robust framework adaptable to any large-scale project. It encompasses the management of the baseline changes, the monitoring of milestones, the planning and coordination of the new facilities installation, and the integration of the HL-LHC installations within the regular LHC maintenance program. Emphasizing the significance of key performance indicators (KPIs), the paper highlights the critical role of metrics as indicators of schedule robustness.

The High-Luminosity LHC project aims to enhance the integrated luminosity of the LHC machine by a factor of 10, by upgrading various components located in the LHC tunnel just before the collision points, with cutting-edge technologies. Among these innovations are the new superconducting magnets equipped with a combination of $Nb-Ti$ and $Nb_3Sn$. conductors. Over 100 magnets are being produced, each undergoing multiple production and test stages across different facilities worldwide, including laboratories outside CERN. Various technology systems are integrated into the magnets, involving collaboration with different groups for assembly work. Recognizing the complexity of this production process, a comprehensive production and test schedule at CERN was established. This paper elucidates the schedule tools implemented to oversee the entire resource loaded process. The compiled data serves to identify strategic or technical bottlenecks in the production flow. By adopting such an approach and simulating various production scenarios, the aim is to proactively address potential conflicts, to ensure the optimal allocation of resources and the readiness for installation during the Long Shutdown 3.

CERN is contemplating further advancements in the energy frontier through the Future Circular Collider (FCC) study, envisioning a 90.7 km underground accelerator with multiple energy stages over time. Following the European Strategy for Particle Physics recommendation in 2020, CERN initiated a feasibility study to scrutinize all aspects of the FCC project. A crucial component of this study involves developing a timeline from project approval to the beam operation of FCC-ee, the first collider with electron and positron. Since the last planning iteration in 2018, modifications in the machine layout and shaft configuration necessitated a re-evaluation of the planning. This paper focuses on the updated planning for FCC-ee, spanning from civil engineering completion to beam operation. It compiles pertinent elements, including the civil engineering release date, layout data, and human resources regulations and limitations. These elements were analyzed systematically to derive a sector sequence. Employing a bottom-up approach in conjunction with resource constraints, an overarching plan for the FCC-ee machine until the start of operations was formulated.