Onboard Communications for Secure and Efficient Driverless Trains

Enrique Bolivar

August 21, 2025

The metro and light rail shift to driverless trains makes onboard communication systems vital for safe, efficient operations.

According to a UITP survey “by 2028 there will be over 3,800 km of automated metro lines in operation worldwide” and “[most] of this growth corresponds to the expected opening of 87 new lines, or extensions of existing lines”.

There are five Grades of Automation (GoA) for trains. These range from driver train control (GoA0) to fully automated train operation with remote monitoring instead of on-board staff (GoA4).

Many challenges are leading transport operators to this transformation:

• Rapid urban population growth
• Enhanced safety and security measures
• Need to control operational costs
• Desire to improve passenger experience
• Commitment to sustainable operations
• Compliance with regulations and laws

An Alstom survey concluded that train automation can help these operators. Automation helps reduce energy consumption by up to 45%. It also provides 30% more passenger capacity and reduces journey time by three minutes. Forward-thinking operators can use digital transformation to improve the travel experience, increase passenger safety and security and enhance their operations.

An essential train “assistant”

Communications capabilities are key for a successful automated train system. Communications among control center staff, train technicians and passengers are mission-critical. They need a high level of security, resilience and availability. Onboard telephony becomes an essential train “assistant” on an automated train. It provides real-time, train-to-ground communications in emergency situations. For example, if a health-related event or aggressive incident occurs on an unattended train, any passenger can call the security team for help using an on-board Emergency Help Point (EHP).

Operational telephony also benefits daily activities. For example, when technicians perform regular maintenance, they need to communicate in real time from the onboard console in the driver’s cabin to the Operations Control Center (OCC). Onboard communications provide this link during maintenance, which increases operational efficiency.

Always-on communication services

The onboard communications solution must be reliable and robust to guarantee always-on service. A recording capability registers all communication between the train and the control center as part of basic operational rules and security measures. If the communications link between the train and the OCC is cut, the onboard telephony system sends a voice message to the passenger to remain on the call while the system recovers the link. In addition, an open platform is vital for integration with the train’s entire control system.

Each railway operator has unique needs. Our Professional Services team has the experience and expertise required to provide tailored solutions that meet our customers’ expectations. We are equipped to design a solution, adapt the current communication solution and enable interworking with third-party elements. ALE Professional Services provided this type of solution for the Grand Paris initiative, with strong project coordination to reduce risk and secure the communications infrastructure.

Onboard telephony is becoming an essential service for passenger safety and security and improved day-to-day operations. ALE’s comprehensive solution portfolio helps railway operators embrace the opportunity for autonomous trains.