Manual Organization

This manual is organized in three main topics to describe the overall preemption process. Chapters 1 through 3 define various aspects of preemption and guide readers to a better understanding of each element involved. Chapters 4 through 7 describe the different design elements and proper implementation of preemption. Chapter 8 discusses the traffic signal and railroad maintenance procedures and responsibilities of the relevant stakeholders.
  • Chapter 1,
    Introduction
    , describes the purpose, common definitions and abbreviations, and existing technical references applicable for this manual.
  • Chapter 2,
    Identifying the Need for Preemption
    , describes how to determine if preemption is needed at a specific location and potential preemption operations.
  • Chapter 3,
    Preemption Time Calculations
    , describes how preemption timing parameters are calculated and how said parameters can determine and affect the overall railroad approach time needed at grade crossings.
  • Chapter 4,
    Railroad Relays and Systems
    , describes railroad relays – including various types, functions, and applicability. It also discusses preemption request forms and limitations of the railroad equipment to consider when implementing preemption.
  • Chapter 5,
    Equipment Standards
    , describes components within traffic signal cabinets and their interface with the railroad equipment during preemption.
  • Chapter 6,
    Interconnected Crossing Design
    , describes design techniques, strategies, guidance, and standards on how to design at grade crossings with traffic signal interconnection.
  • Chapter 7,
    Construction and Implementation
    , describes the preemption implementation process and defines the responsibilities of TxDOT and the appropriate railroad authority as related to traffic signal interconnection.
  • Chapter 8,
    Inspection and Maintenance Considerations
    , describes the necessary inspection and maintenance processes to identify and troubleshoot the quality and functionality of existing preemption operations.