UIC Leaflet 751-1: Technical Specifications for Ground-to-Train Radio Systems

What is UIC Leaflet 751-1?

UIC Leaflet 751-1 is a core technical document titled “Railway radio equipment – Ground-to-train radio systems.” It establishes the mandatory technical parameters for the wireless communication infrastructure that connects train drivers with traffic control centers.

Reliable Ground-to-Train Radio is a prerequisite for Operational Safety. Without it, dispatchers cannot issue emergency stop orders or provide real-time updates on track conditions. UIC 751-1 ensures that these systems are robust, secure, and capable of functioning across borders, which is essential for Interoperability.

Functional Requirements for Voice and Data

The leaflet specifies the essential services that the radio system must support. These requirements formed the “Functional Requirement Specification” (FRS) for the modern GSM-R standard:

• Point-to-Point Voice Calls: Direct communication between the driver and the controller.
• Group Calls: The ability to broadcast a message to all trains within a specific geographical area or “cell.”
• Emergency Calls: A high-priority “Railway Emergency Call” that can preempt any ongoing non-safety communication.
• Shunting Communication: Specific protocols for low-speed, high-frequency coordination during Shunting Operations.
• Data Transmission: Support for low-bandwidth data exchange, such as train identification and location reporting.

Technical Standards and Coverage

UIC 751-1 dictates the physical and electromagnetic performance of the Transmission Systems:

• Radio Coverage: Guidelines for signal strength (measured in dBm) along the track, including the requirement for 95% probability of coverage in tunnels and deep cuttings.
• Frequency Management: Allocation of specific frequency bands to prevent interference from public mobile networks.
• Handover Performance: Requirements for the seamless transition of the signal between base stations as a train travels at high speeds.

Transition to GSM-R and EIRENE

While historical versions of UIC 751-1 focused on analog radio systems (such as the UIC 751-3 “Type B” or “Type C” systems), the modern application of this leaflet is integrated into the EIRENE project. EIRENE utilized the functional needs of UIC 751-1 to develop the GSM-R (Global System for Mobile Communications – Railway) standards currently used across the European rail network and beyond.

Comparison: Analog vs. Digital (GSM-R) Radio Systems