RaSTA Protocol Stack
Client:
SBB
Date:
Feb 28, 2022
About the Customer and the Project
The advancing digitalization in the railway sector presents new challenges for railway infrastructure operators. Particularly the integration and communication between different systems impose high demands on safety and efficiency.
In this context, SBB participated in the European initiative EULYNX, which aims to standardize interfaces and signaling systems.
For this purpose, SBB realized a Proof of Concept (PoC), with CSA as a close partner implementing the integration of the Rail Safe Transport Application (RaSTA) Protocol Stack.
Our Services
As part of modernizing its railway infrastructure and introducing EULYNX architectures, SBB evaluated the possibility of running safe and non-safe applications on the same embedded platform.
An integral component is the RaSTA Protocol Stack – a safety-critical communication stack that ensures reliable and standard-compliant data transmission between interlocking systems and object controllers. The development was carried out according to railway standards EN50128, EN50126, and EN50159, adhering to the highest Safety Integrity Level (SIL4).
CSA took on the complete development and integration of the RaSTA Protocol Stack for SBB, based on Aviotech's SCORPOS platform. Throughout the project, all system components were developed according to the V-model – including specification, implementation, verification, and validation.
A key component was the integration of the stack on the two-channel SCORPOS platform with spatially and temporally segregated partitions, allowing multiple applications to run independently and deterministically.
The RaSTA Stack is split across two partitions: Safety and Retransmission Layer (SIL4) and Redundancy Layer (Basic Integrity). Physically, each channel uses an Ethernet interface with a RaSTA channel. This channel is continuously checked by a heartbeat. Additionally, TCP/IP, TLS, and OPC-UA were implemented on further partitions.
The entire development process was accompanied by thorough technical documentation and concluded with a successful TÜV inspection report at the end of 2022.
Furthermore, the project results were presented by SBB at the EUG Safety Conference in October 2022.
Thanks to these comprehensive services, CSA effectively supported SBB in developing a SIL4-compliant system and ensuring that all safety-critical requirements were fully met.
Further details can be found in the following blog post:
https://www.csa.ch/blog/sil4-protocol-stack-railway-industry
Created Value
Through CSA's expertise in embedded software, standards, and project management, a certifiable reference implementation of the RaSTA Protocol Stack was realized for SBB within an efficient project setup. This enables SBB to gain important insights about the EULYNX standard and the requirement specifications based on it. The use of the RaSTA Stack in a PoC can also demonstrate the feasibility of a requirement.
Together with SBB, CSA was able to make a significant contribution to modernizing the railway infrastructure through successful implementation.
Additionally, an open-source RaSTA Stack reference implementation is available to the public: https://github.com/SchweizerischeBundesbahnen/sbb-rasta-stack
EULYNX in Use - CSA Field Elements as Part of the DB Demonstrator
Client:
DB
Date:
Apr 8, 2022
As part of the "Moving Block Demonstrator" project at the Digital Railway Test Facility (Erzgebirge), CSA Engineering has completed a proof of concept for the EULYNX Object Controller for specific field tests by Deutsche Bahn.
Field Element of the EULYNX PoC Platform
Client:
SBB
Date:
Mar 15, 2022
The platform is deployed at the Löwenberg test facility near Murten and enables practical verification of EULYNX-compliant systems under realistic conditions.