In modern rail transit systems, touch screen HMIs are everywhere: in the driver’s cab, passenger information displays, door control panels and emergency intercom units. These devices, such as the EN 50155 railway touch screen HMI, must survive constant vibration, temperature swings, humidity and electrical noise on rolling stock, while still delivering a safe and readable user experience.

The European standard EN 50155 defines operating conditions for electronic equipment used on railway vehicles, including limits for temperature, humidity, shock, vibration and EMC. Meeting this standard, and related requirements such as IEC 61373 shock and vibration tests and EN 45545 fire safety rules, is essential for any serious on-board display project. This article translates those high-level requirements into ten practical engineering improvements for railway touch screen HMIs.

If you are still comparing hardware options, you may want to read our Industrial Touch Screen Buyer’s Guide first. For system-level examples in trains, metros and buses, see our transportation touch screen solution page.

1. High Vibration Resistance to Meet EN 50155 and IEC 61373

Pain point

Rolling stock equipment is exposed to constant vibration, shocks and occasional impacts from track joints, switches and emergency braking. Standard commercial displays may suffer cracked solder joints, loose connectors or intermittent touch faults under these conditions.

Engineering improvement

The touch screen HMI should be designed from the ground up for railway vibration profiles. That means:

• Using an industrial PCAP touch module and LCD rated for railway applications.
• Reinforcing connectors, cables and heavy components with mechanical supports and adhesive where appropriate.
• Mounting the module with a rigid frame and defined screw torque, and sharing a common ground between LCD, touch controller and chassis to reduce electrical noise.
• Qualifying the complete assembly to IEC 61373 shock and vibration tests and EN 50155 operating conditions for rolling stock electronics.

Result

With proper mechanical design and testing, the HMI maintains stable operation on bogies, end cars and cabs, even after years of service. Random resets and intermittent touch faults caused by vibration are greatly reduced.

2. Wide Operating Temperature from -40 °C to 70 °C

Pain point

Railway displays are used in driver’s cabs, outdoor platforms and unconditioned technical rooms. In many regions they must work from about -40 °C in winter up to 70 °C inside sun-heated housings in summer. Consumer-grade components cannot withstand this range.

Engineering improvement

The HMI should use wide-temperature LCDs, PCAP sensors, controllers and power components rated for at least -40 °C to 70 °C. In cold climates, a heater film or controlled warm-up mode can protect the LCD from low-temperature damage. Thermal simulations, airflow design and careful placement of heat-generating parts will help the system stay within safe limits. Our buyer’s guide explains how to choose display and touch components for such conditions.

Result

The display remains responsive in winter depots and hot tunnels alike. Temperature cycling has less impact on lifetime, and the operator avoids seasonal failures.

3. Anti-Glare and Sunlight Readability for Passenger Information

Pain point

Passenger information displays in trains and at platform edges must stay readable in strong sunlight, reflections from glass and mixed indoor lighting. Plain glossy glass causes heavy reflections, making route maps and safety messages hard to read.

Engineering improvement

To improve readability:

• Use AG (anti-glare) or AR (anti-reflective) coated cover glass with controlled haze.
• Specify a high-brightness backlight, for example 800–1000 nits or above for outdoor-facing displays.
• Apply optical bonding between LCD and cover glass to cut internal reflections and increase contrast.
• Combine this with an ambient light sensor and automatic brightness control to avoid dazzling users in tunnels or at night.

These methods are explained in more detail in our sunlight readable display guide and the article on optical bonding for industrial touch screens.

Result

Timetables, route diagrams and emergency instructions stay readable under direct sunlight and mixed lighting. At the same time the screen automatically dims in dark tunnels, improving comfort and safety.

4. Long-Lifetime Backlight and 24/7 Reliability

Pain point

Passenger information systems often operate 24 hours a day, 7 days a week. Displays that are not designed for continuous operation may suffer from early backlight failure, image retention or colour shift.

Engineering improvement

A railway-grade HMI should:

• Use long-lifetime LED backlights rated for 50,000–70,000 hours or more at the expected operating temperature.
• Include intelligent dimming curves to reduce stress during low-light periods.
• Implement health monitoring for backlight current and temperature, reporting pre-fail conditions to the train control system.
• Follow robust PCB design and conformal coating practices to prevent corrosion and extend lifetime.

Result

The display provides stable brightness for many years of service, reducing replacement intervals and maintenance cost.

5. Sealed IP65 Front for Dust and Water Protection

Pain point

Rail vehicles encounter dust, moisture, cleaning agents and sometimes direct water spray in depots. If the HMI front is not sealed, moisture can reach the electronics and cause corrosion or intermittent faults.

Engineering improvement

The front of the touch screen should be designed for at least IP65 protection in exposed locations. A flat, sealed front with gasket or bonding adhesive around the perimeter prevents water ingress and makes cleaning easier. Design principles similar to our IP65 waterproof touch screen design guide apply, with extra attention to cable glands, venting and pressure equalisation.

Result

The HMI withstands regular cleaning and occasional splashes without water creeping into the housing. Failures caused by moisture and dust are significantly reduced.

6. Robust EMC Design for Noisy Railway Environments

Pain point

Power converters, traction inverters, braking systems and radio equipment on trains can generate significant electromagnetic noise. Poor EMC design may lead to ghost touches, frozen screens or misbehaving electronics.

Engineering improvement

Good EMC practice includes:

• Shielded cables and connectors between the touch screen, controller and vehicle electronics.
• Proper grounding and bonding between LCD, touch controller, power board and metal chassis.
• Filtering on power inputs and signal lines according to EN 50155 categories.
• PCB layout that separates noisy and sensitive circuits, following vendor application notes and installation guidelines.

Result

Even with high-power traction equipment nearby, the touch screen operates correctly without ghost touches or unexpected resets. This improves both safety and user confidence.

7. Multi-Language UI for International Passengers

Pain point

Rail networks serve local commuters, international travellers and tourists. A single-language interface on passenger displays and ticket machines can confuse non-native speakers and increase support load.

Engineering improvement

The HMI software should support multiple languages and clear iconography. At the start screen, passengers can select their preferred language with one tap. The layout must reserve enough space for longer text strings, and important safety messages should combine icons with multilingual text. Our application-based solution hub shows how we apply similar multi-language strategies to kiosks, EV chargers and ticketing machines.

Result

Passengers can quickly understand route information, door instructions and emergency messages in their own language. This improves usability and the overall perception of the rail operator.

8. Integrated Emergency Call and Safety Functions

Pain point

Emergency communication units in trains and at platforms need to be easy to understand and operate, even under stress. If the touch interface is confusing or too sensitive, passengers may struggle to call for help.

Engineering improvement

Emergency call panels can combine a large, physical emergency button with a clear touch screen workflow. The PCAP controller should be tuned for strong anti-mistouch performance around the emergency area. On-screen prompts guide the passenger through the conversation and display status information such as “Call Connected” or “Help on the way”. These user experience ideas are aligned with the principles in our article on intuitive touchscreen interface design.

Result

Passengers can reliably trigger emergency calls and receive feedback. Train staff and control centres gain clearer information about the incident, which improves overall safety.

9. Fire Behaviour and Explosion Risk Reduction (EN 45545)

Pain point

Rail vehicles are enclosed spaces where smoke, heat and toxic gases can spread quickly in a fire. Materials that burn easily or generate dense smoke increase risk for passengers and staff.

Engineering improvement

Materials used in the touch screen HMI—cover glass, plastics, gaskets, cables and PCBs—should follow the fire behaviour requirements of EN 45545-2 and related parts of the EN 45545 series. This includes selecting low-flammability materials, controlling smoke density and limiting toxic gas emissions. For equipment installed in hazardous areas, additional explosion-proof or spark-limiting measures may be needed, depending on the operator’s risk assessment.

Result

If a fire does occur, the HMI contributes as little as possible to flame spread and smoke generation. Combined with other vehicle fire protection measures, this increases the time available for safe evacuation.

10. System-Level Certification and Documentation

Pain point

Even when individual components claim compliance, incomplete documentation or missing test reports can delay approvals and tenders. Operators and vehicle integrators need clear evidence that the HMI meets railway standards.

Engineering improvement

From an early project phase, plan a certification path that covers:

• EN 50155 for electronic equipment on rolling stock, including operating conditions, EMC and environmental stress.
• IEC 61373 shock and vibration testing for on-board equipment.
• EN 45545 parts 1 and 2 for fire behaviour of materials and components on railway vehicles.

Compile a technical file that includes test reports, component declarations and installation guidelines. Link the HMI’s design and test results to system-level safety cases and operator requirements. Our industrial touch screen solution overview explains how we approach this cross-industry.

Result

Vehicle builders and operators receive a clear package of documentation that supports acceptance, safety cases and future audits. This reduces project risk and speeds up time-to-market for new rolling stock and retrofit programs.

Conclusion: Building a Railway-Grade EN 50155 Touch Screen HMI

Designing touch screen HMIs for rail transit is very different from building consumer tablets or simple indoor displays. Vibration, temperature, glare, EMC, fire safety and passenger expectations all place heavy demands on the hardware and software.

By applying these ten engineering improvements—vibration resistance, wide temperature range, glare control, long-lifetime backlights, IP65 sealing, robust EMC design, multi-language UI, integrated emergency functions, EN 45545-compliant materials and full system-level certification—you can build railway HMIs that are both robust and user-friendly.

If you are working on a new rolling stock project or upgrading an existing fleet, our engineering team can help you specify the right PCAP touch screen, display module and housing. You can reach us through the inquiry form on our Contact Us page.