EN 50155 is the primary railway standard
Verify EN 50155 compliance before specifying any switch for rolling stock. It covers temperature, vibration, power supply, and EMC.
21.1 Railway and Transportation Networks
The previous chapters covered general industrial networking. Railway and transportation networks add a layer of requirements that standard industrial equipment cannot meet: vibration, wide temperature ranges, fire protection, and electromagnetic compatibility in moving vehicles. This section covers the standards, design considerations, and Hirschmann products for railway applications.
Railway Standards
Section titled “Railway Standards”Railway networks must comply with standards that define environmental, safety, and EMC requirements for equipment installed in or near railway vehicles.
| Standard | Scope | Key Requirements |
|---|---|---|
| EN 50155 | Electronic equipment for rolling stock | Temperature, vibration, humidity, power supply, EMC |
| EN 45545 | Fire protection in railway vehicles | HL3 = highest fire protection level |
| EN 50121-4 | EMC for railway trackside equipment | Radiated and conducted emissions/immunity |
| E1 | Road vehicles (ECE R10) | EMC for road vehicles |
| NEMA TS2 | Traffic control systems (North America) | Environmental and electrical requirements |
Key terms:
- EN 50155 — the primary standard for electronic equipment installed in railway rolling stock; defines temperature classes (T1 to T6), vibration levels, and power supply requirements
- EN 45545 — fire protection standard for railway vehicles; HL3 is the highest hazard level, required for underground and tunnel applications
- Rolling stock — railway vehicles that move on the track (trains, trams, metros)
- Trackside — equipment installed alongside the track (signals, switches, communication infrastructure)
Network Topology for Rolling Stock
Section titled “Network Topology for Rolling Stock”A train consists of multiple carriages. Each carriage has its own local network. The carriages connect to each other through inter-carriage links.
The inter-carriage links use M12 connectors because they withstand vibration and provide IP67 protection. RJ-45 connectors would loosen under the vibration of a moving train.
M12 Connector Types
Section titled “M12 Connector Types”M12 connectors are circular industrial connectors used in railway and harsh-environment applications. Different coding variants prevent incorrect connections:
| Coding | Pins | Use |
|---|---|---|
| A-coded | 4 or 5 | Power supply, sensors, V.24 serial |
| D-coded | 4 | Fast Ethernet (100 Mbps) |
| X-coded | 8 | Gigabit Ethernet (1000 Mbps) |
The BXS and BXP switches use M12 X-coded ports for Gigabit Ethernet and M12 D-coded ports for Fast Ethernet. The OCTOPUS managed switches use M12 connectors throughout.
Hirschmann Products for Railway
Section titled “Hirschmann Products for Railway”| Product | Standard | Key Feature |
|---|---|---|
| BXS | EN 50155, EN 45545 HL3, EN 50121-4 | TSN, PoE, M12, IP40 |
| BXP | EN 50155, EN 45545 HL3 | 10G, PoE++, bypass function |
| OCTOPUS managed | EN 50155, EN 50121-4 | IP67, M12, Layer 3 routing |
| BAT450-F | EN 50155, E1 | WLAN, IP67, V.24 train coupling |
| EAGLE One | EN 50121-4 | Firewall, trackside |
The bypass function on the BXP is critical for rolling stock. If the switch loses power, the bypass maintains the physical Ethernet connection between the ports. Traffic continues to flow even when the switch is unpowered.
Key Takeaways
Section titled “Key Takeaways”Use M12 connectors for rolling stock
M12 connectors withstand vibration and provide IP67 protection. RJ-45 connectors are not suitable for moving vehicles.
What Comes Next
Section titled “What Comes Next”Railway networks operate in controlled environments. Substation automation networks operate in high-voltage environments with strict timing requirements. The next section covers substation-specific standards and Hirschmann products certified for substation use.
References
Section titled “References”- EN 50155:2017 — Railway applications — Rolling stock — Electronic equipment
- EN 45545-2:2013 — Railway applications — Fire protection on railway vehicles
- EN 50121-4:2016 — Railway applications — Electromagnetic compatibility — Part 4: Emission and immunity of the signalling and telecommunications apparatus
- Hirschmann. (2024). Belden/Hirschmann Essentials 2024. Belden.