UIC Leaflet 750: Service Telecommunications for International Railway Operations

What is UIC Leaflet 750?

UIC Leaflet 750 is the primary regulatory document titled “Railway Service Telecommunications.” It establishes the framework for the voice and data networks used by railway staff for the management, operation, and maintenance of the rail system.

In an international context, Interoperability requires that telecommunication systems be compatible across borders. This leaflet ensures that a train driver entering a foreign network can communicate with the local traffic controller using standardized equipment and protocols, which is a fundamental requirement for Operational Safety.

Core Functional Requirements

UIC 750 outlines the specific services that a railway telecommunications network must provide. These are categorized based on their criticality to operations:

• Train-to-Ground Communication: The most critical link, allowing real-time voice contact between the driver and the dispatcher for traffic movement and emergency reporting.
• Station and Shunting Communications: Short-range radio or wired systems for coordination during Shunting Operations and passenger management.
• Maintenance and Technical Services: Dedicated channels for trackside maintenance crews to communicate with control centers regarding track possessions and work zone safety.
• Emergency Call Functionality: Standardized priority protocols that allow emergency messages to override regular traffic on the network.

Evolution and GSM-R

While the historical versions of UIC 750 covered analog radio and wired telephone systems, modern applications are heavily centered on GSM-R (Global System for Mobile Communications – Railway).

UIC 750 provided the functional basis for the transition to digital Ground-to-Train Radio. It defines the “User Requirements” that the technological standards (like those from ETSI) must fulfill to be suitable for the railway environment, such as high-speed handovers between base stations and operation in tunnels.

Network Performance and Reliability

Because these systems are essential for safety, UIC 750 sets strict Transmission Systems performance criteria:

• Availability: The network must be available 99.9% of the time, especially in safety-critical zones.
• Coverage: Continuous signal strength must be maintained along the entire length of the track, including deep cuttings and tunnels.
• Prioritization: Multi-level Pre-emption and Priority (MLPP) is required to ensure that a “Train Emergency” call can “kick” a lower-priority administrative call off the network.

Comparison: Railway Service vs. Public Telecommunications