Advancing rail signaling modernization: Aligning delivery, operations and integration

Strategic delivery models and system planning can reduce risk, improve efficiency and unlock long-term value for transit agencies

Transit agencies are modernizing their rail systems to meet rising demand and address aging infrastructure. In 2023, total rail transit miles traveled increased by 12% over the previous year, according to the Federal Transit Administration. In response to this upward trend, transit agencies are upgrading their systems to deliver significantly higher levels of capacity, reliability, safety, automation and cost-effectiveness over the system lifecycle.   

While modernization efforts are powered by advanced technologies, agencies that clearly define how they intend to deliver, operate and equip their systems from the outset create favorable conditions for these technologies to work in concert to improve coordination, minimize risk and support long-term performance. 

While many elements contribute to modernization success, the delivery model, concept of operations and rolling stock strategy are particularly influential in driving alignment, managing risk and controlling costs early in a project. Each represents a critical decision point that, when addressed proactively, establishes a foundation for long-term success. 

Delivery model: Structuring for integration and control 

For rail signaling modernization, delivery strategy is not a contractual formality, it materially influences risk posture, schedule predictability, lifecycle costs and technical outcomes. Early decisions in this area affect how integration is managed and how effectively operational requirements are translated into system behavior. 

For example, several delivery models have been used successfully in CBTC modernization: 

• Design-Build (DB): Commonly applied to streamline CBTC implementation by unifying design and construction under one contract. DB can shorten delivery timelines and simplify procurement. It requires clear performance requirements for specifications and early coordination with the systems integrator to preserve owner visibility into technical decisions. 

• Design-Build-Maintain (DBM): Adds long-term maintenance responsibility to the DB model. This approach can improve life cycle performance and accountability. It demands clearly defined interface roles and robust performance metrics to manage ongoing obligations. 

• Progressive Design-Build (PDB): Gains traction in CBTC programs with high integration risk. PDB enables early collaboration between the owner and contractor, allowing design development and cost refinement to evolve jointly before construction is finalized. This supports iterative resolution of technical challenges and better alignment with system performance needs. 

• Alliance Contracting: Embeds owner, designer, contractor and suppliers into a single governance structure. This model promotes shared success metrics and transparent problem-solving but requires organizational maturity and cultural readiness for joint risk sharing and delivery. 

Regardless of model, several implementation factors strongly influence CBTC outcomes: 

• The timing of systems integrator engagement 

• Clarity of interface definitions  

• Configuration control during iterative design and testing 

These elements are essential to reducing integration risk and aligning delivery with operational intent. 

Concept of operations: Translating strategy into system behavior 

Once the delivery structure is in place, agencies need a clear operational vision to guide design and integration. A well-defined Concept of Operations (ConOps) connects strategic goals — such as service frequency, reliability, safety and automation — to the technical and behavioral requirements that will bring them to life. 

For CBTC programs, the ConOps defines how the system should function under both normal and degraded conditions, establishes the intended Grade of Automation (GoA), and clarifies how operators, maintainers and fallback systems will interact with new signaling technologies. It serves as the operational anchor point for technical decisions throughout the program. 

Developing a strong ConOps requires input from operations, safety, maintenance, IT and asset management teams to address real-world service conditions, workforce expectations and system constraints. Capturing this input early ensures that the ConOps reflects not just what is possible, but what is practical and sustainable. 

When actively referenced throughout the program, the ConOps supports consistency in system design, interface management, testing, training and commissioning. It becomes a living tool that keeps teams aligned across phases and helps ensure that the delivered system performs as intended. 

Rolling stock strategy: Managing complexity at the system edge 

While the ConOps defines how the system is intended to operate, those expectations rely on vehicles that are properly equipped to deliver. Ensuring both revenue and nonrevenue trains are integrated effectively with CBTC is essential to realizing the system’s full operational potential. 

Some trains may be near end-of-life and often have inconsistent configurations due to years of maintenance and upgrades. This adds complexity, cost and schedule risk. Still, purchasing new trains may not be feasible, requiring careful evaluation of lifecycle value and program impact. 

Nonrevenue vehicles, such as work trains, also present trade-offs. Choosing not to equip them increases demand on secondary detection systems. Equipping them requires accounting for unique operational behaviors — like push-pull movement, decoupling and cold starts — that impact software, logic and testing. 

Key technical constraints for both vehicle types include: 

• Space for onboard equipment 

• Power capacity to support new systems 

• Network capabilities for CBTC data 

• Propulsion and braking integration 

Addressing these factors early — through audits, feasibility studies and rollout planning — helps agencies ensure reliable, cost-effective integration that supports overall system performance. 

Building the future of rail transportation 

Rail signaling modernization is more than a technology upgrade — it is an opportunity to transform how transit systems operate. By proactively defining delivery models, ConOps and rolling stock strategy, agencies can reduce risk, improve alignment and enable smarter deployment of advanced technologies. 

Modernization success depends not only on what is delivered, but how it is delivered. With a clear technical architecture and cohesive planning framework, agencies can create systems that meet today’s needs and scale for tomorrow’s demands.