Integrated into Daily Life: USB-C and USB-C Power Delivery for Use in Rail Vehicles
Rail technology specialist LÜTZE TRANSPORTATION offers a comprehensive range of rail-compatible USB charging solutions for rail vehicles. Following the introduction of the first USB-C solutions, USB-C charging solutions with Power Delivery are now available for daily use in rail vehicles. In the near future, USB-C Power Delivery solutions with up to 240 watts of power will be available in rail vehicles. This could make Schuko sockets in passenger areas and driver cabs largely obsolete.
Increased use of Mobile Devices on Trains
The need for tamper-proof charging infrastructure is growing.
Mobile devices such as smartphones and tablets are now indispensable in our lives. Accordingly, the daily usage time of smartphones in Germany averages around 2.5 hours. The use of mobile devices among train passengers in local and long-distance travel is also continuously increasing. Evidence of the growing use of mobile devices on trains is the rising use of Wi-Fi in long-distance trains. Deutsche Bahn documented that in 2018, about 30 terabytes of data were transmitted monthly via the Wi-Fi network in ICE trains, and this data volume increased to about 50 terabytes per month in 2019. Train drivers and conductors also use tablet PCs and laptops to access timetables, route information, and emergency protocols in real-time.
With the increasing use of mobile devices on trains, the demand for appropriate charging options is rising. Since the early 2000s, Deutsche Bahn has installed Schuko sockets for charging mobile devices in its trains. However, with the introduction of Schuko sockets, issues with vandalism have repeatedly occurred: sockets were tampered with, endangering the health of unsuspecting travelers. Overuse from simultaneously connecting multiple or high-power devices is also a known issue.
To address these challenges, rail vehicle manufacturers and operators are increasingly relying on USB charging infrastructure in passenger areas. Since around 2015, Deutsche Bahn has begun installing USB-A sockets in its trains.
In October 2022, the European Union adopted a directive mandating USB-C as the standard connection for many electronic devices, replacing USB-A and other USB plug variants. This requirement is expected to lead to USB-C charging infrastructure becoming the sole standard in European rail vehicles in the near future.
LÜTZE TRANSPORTATION has been offering various charging systems for rail vehicles for many years. In addition to the proven USB-A variants, with and without Schuko sockets, USB-C variants are now also available. Due to demand from non-European regions, USB-A variants will continue to be supplied. All charging systems from LÜTZE TRANSPORTATION meet the rail-related standards EN 50155, EN 50121-3-2, EN 61373, EN 45545-2, as well as Regulation No. EMV 06 of the Federal Railway Authority. Thanks to EMV 06, which regulates electromagnetic compatibility with railway radio services, retrofits by the operator are possible.
LÜTZE focuses on USB-C for Rail Vehicles
In early 2024, LÜTZE introduced its first charging units with two USB-C ports, suitable for both passenger areas and driver cabs. Additionally, these charging units feature a classic Schuko socket (Type F/CEE 7/3). The compact sockets are suitable for installation in passenger areas and driver cabs. USB-C offers significantly better mechanical durability compared to USB-A, with up to 10,000 insertion cycles, and is independent of plug orientation.
The 230 V sockets with two USB-C charging ports provide a charging current of 1.5 A each at 15 W. If only one port is used, a charging current of up to 3 A is available. The USB-C charging ports use less than 50 mW in standby mode, thereby minimally loading the onboard networks. Thanks to the dynamic detection of the charging protocol, the power requirement of the connected mobile device is recognized and the charging current is adjusted accordingly.
Powerful USB-C PD charging ports for passenger areas
However, as previously described, Schuko sockets are not tamper-proof, and traditional USB-C ports offer insufficient power for high-power laptops, for example. The standard USB-C specification is limited to 5 V and a maximum of 3 A (15 W).
LÜTZE TRANSPORTATION has therefore now included USB-C charging solutions with PD (Power Delivery) in its range. With USB PD, significantly higher charging powers can be achieved. LÜTZE TRANSPORTATION offers USB-C charging solutions with 3 A power and up to 20 V, and is working on next-generation solutions that are expected to support up to 5 A according to the USB Power Delivery 3.1 specification.
An important advantage of Power Delivery is the "Handshake," which ensures compatibility between device and charger and negotiates optimal voltage and current. This prevents overloading of the charger and battery.
With the new USB-C charging ports for passenger areas offering 65 watts, LÜTZE TRANSPORTATION presents 100% rail-compatible charging systems, and offers OEMs and rail operators the possibility to completely eliminate 230 V Schuko sockets in passenger compartments. The LÜTZE USB-C socket delivers 65W output power at 5 to 20V, and up to 3.25A, sufficient for powerful laptops and tablets. With an energy efficiency of over 80% and a standby consumption of under 50mW, the onboard power system is minimally burdened. Continuous operation is possible at temperatures from -25 to +55 °C, with a service life of 20,000 operating hours at full load.
With dimensions of 40 x 42 mm and a depth of 40 mm, the system is significantly more compact and space-saving than traditional Schuko socket units. This makes it ideal for installation between seats or into the cabin walls.
During the development of the new USB-C sockets, particular emphasis was placed on safety. The system is completely tamper-proof. The passenger-side front cover is clicked into place from the front and must be released from the back. It is also not screwed on, making the USB socket inaccessible from the passenger side. The USB system operates on the input side with AC 230 V and delivers a maximum of 20 V on the output side. This means there is no risk of electric shock for passengers.
USB-C Power Delivery charging system for the driver's cab
The demand for more powerful USB charging systems is also high in the driver’s cab. LÜTZE TRANSPORTATION supplies a 60 W Power Delivery charging system with a DC/DC converter and an input voltage range of DC 24 - 110 V as a wide-voltage supply, including a two-meter charging cable and USB-C port. The USB-C charging system offers a significant power increase over the proven USB charging system with two USB-A ports. This enables efficient use of high-power laptops and tablets to conveniently update travel data, such as route tables, schedules, and speed restrictions.
A key advantage is the compatibility of the dimensions of the DC/DC converter and charging cable with the existing USB-A system. Operators can easily upgrade to the new USB-C system by simply replacing the converter without changing the wiring on the input side. No additional installation space is required, and the charging cable can be replaced 1:1. The converter is mounted on DIN rail TS35-15 or TS35-7.5 (EN 60715).
Thanks to the wide input voltage range of DC 24 V to 110 V, the DC/DC converter can be used in both diesel and electric vehicles. The output provides 3 A at 5 to 20 V DC. The new USB-C system is suitable for installation in the driver’s cab or in small control cabinets.
The USB-C charging system is designed for continuous operation in the temperature range of -40 °C to +70 °C. The DC/DC converter features reverse polarity protection on the input side. On the output side, it provides short-circuit and overload protection. The output voltage is indicated by a separate green LED. The charging cable is two meters long. An adequate conductor cross-section ensures a low voltage drop.
Background on USB-C
Key requirements and goals of the USB-C EU directive include:
- By the end of 2024, all small and medium-sized portable devices must be equipped with USB-C, including smartphones, tablets, e-readers, cameras, headphones, speakers, and handheld consoles.
- By spring 2026, laptops must also have USB-C charging ports.
- Devices with fast-charging functions must offer the same charging speed regardless of the charger.
- The directive aims to reduce electronic waste by eliminating different types of chargers and cables.
- Standardized charging ports are expected to enhance consumer protection and convenience by reducing the need for various chargers and cables.
Background on USB PD Power Delivery
- USB Power Delivery 1.0 was introduced in July 2012. It enables power delivery of up to 100 watts (20 V, 5 A).
- USB Power Delivery 2.0 was released in August 2014. This version introduced improvements in device communication. USB PD 2.0 was the basis for the introduction of USB-C.
- USB Power Delivery 3.0 was released in September 2015. This version added the ability to monitor charging status and improved energy management protocols.
- In 2017, the USB PD 3.0 specification was extended with the "Programmable Power Supply" (PPS) feature, allowing dynamic adjustment of voltage and current, which is particularly advantageous for fast charging.
- The USB PD Revision 3.0, Version 1.1 from 2019 introduced additional safety measures and further optimized communication protocols.
- The latest specification, USB Power Delivery 3.1, was released in May 2021. This version increased the maximum power to 240 W (48 V at 5 A).
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Authors: Andreas Schindler and Yima Zimmermann, Product Managers at Lütze Transportation GmbH, Weinstadt
Sources:
www.bitkom.org/Presse/Presseinformation/Durchschnittliche-Smartphone-Nutzung-pro-Tag
www.br.de/nachrichten/bayern/stromschlaggefahr-warnung-vor-manipulierten-steckdosen-in-zuegen,Tna2oAD
www.zdf.de/nachrichten/panorama/kriminalitaet/bahn-steckdose-manipulation-bundespolizei-warnung-100.html
ec.europa.eu/commission/presscorner/detail/en/ip_21_4613