The legacy LonWorks network communications standard is still in service on thousands of passenger trains around the world. The transition of LonWorks hardware to end-of-life status in 2024 has become a critical issue for transit authorities and operators. Fleet operational readiness and budgets are at risk unless a smart plan for support and transition is funded and executed quickly.
This post will discuss the history of LonWorks, the potential impacts of its obsolescence, and our recommendation for the best choice of technology and support to make the transition as smooth as possible.
Why has LonWorks been used on passenger trains?
LonWorks is a network communications protocol that was developed in the late 1980’s. It has been used in many different industrial automation applications, with an estimated installed base of over 90 million devices. In passenger rail, LonWorks has often been used for the onboard networked backbone of electronics-based systems and equipment.
In the arc of its life cycle, LonWorks is now considered a legacy protocol at best, or end-of-life at worst. But in its day, it was a market leader in the emerging digital communications market. It had some unique features over traditional methods of control and automation, including:
- Peer-to-peer distributed architecture
- No central PLC required
- Good fault isolation
- Reduced wiring vs traditional relay logic
- Strong tool ecosystem in the 1990s
- Reliable and robust in ‘dirty’ electrical environments
But, it had a few weaknesses too:
- Low bandwidth (~78 kbps typical)
- Vendor-tool dependent
- Not well-suited for modern high-data applications
- Does not meet modern IT requirements for cybersecurity
After 2010, LonWorks technology was considered a legacy technology, meaning ‘not to be used for new design’ and gave way to other higher bandwidth protocols, including:
- Ethernet Train Backbone (ETB)
- Ethernet Consist Network (ECN)
- CANopen
- MVB
Today, even though LonWorks is not actively used in new designs for communication systems on trains, there are many trains still in service that were designed and built from 1990 to 2010 when LonWorks was the chief communication bus onboard.
With the obsolescence of Lonworks chipsets, transit authorities and operators are searching for cost-effective ways to replace LonWorks networking equipment on their fleets, to help renew and maintain them going forward.
What LonWorks end-of-life means for your trains
Beyond the technology itself, several pivotal changes are responsible for taking LonWorks from legacy status to obsolete.
The main changes started in 2018, when LonWorks technology was transferred through several company acquisitions, resulting in the obsolescence of the LonWorks hardware chipsets. This signaled the end of the technology’s useful life.
There have been some moves to provide support by promoting the software and configuration side of the protocol, e.g., development tools and software stacks that can run on non-LonWorks processors. But these will only serve to interface with LonWorks systems that are in transition. These systems are essentially on ‘life support’ waiting for the funding and the cost-benefit analysis that will unlock and convert legacy LonWorks systems into something newer.
The obvious question for transit operators and maintainers is, “What are my options to support and transition from LonWorks-based networks and equipment?”
The best choice for moving on from LonWorks
The main replacement option for LonWorks is Ethernet-based technology and protocols that were developed by the rail industry under what is now IEC 61375 – Train Communication Network (TCN).
This standard had its first major revision in 2012 and now includes expanded applications for higher data rate applications and specifications for the physical interfaces (e.g., optical, wired). It is now considered the modern digital communication specification for rail network communications.
The standard considers network communication:
- within a train car, as per IEC 61375-3-4 Ethernet Consist Network (ECN)
- between consists, as per IEC 61375-2-5 Ethernet Train Backbone (ETB)
Compared to LonWorks, these higher bandwidth Ethernet networks allow for a significant increase in the ability and complexity of rail applications. This includes wayside connectivity, onboard Wi-Fi, CCTV video streaming, and cybersecurity.
It’s easy to look back and say LonWorks is not that useful compared to Ethernet today, but at the time, it was an elegant engineering solution, thanks to being reliable, robust and well suited for the technological level of trains at the time it was being specified.
The obvious choice for replacement is Ethernet-based technology, but the transition can be costly as transit authorities continue to require high reliability and expanding applications to support operations, enterprise integration, and the high-tech passenger experience to enhance ridership.
This means that moving from LonWorks to Ethernet in a retrofit application for trains can be challenging, as it may not always end up as a lower cost. This is often due to the temptation to expand functionality beyond what was originally provided by LonWorks.
Sound engineering and strong integration skills are necessary to surgically transition to Ethernet from LonWorks. In our next post, we’ll discuss recommended steps to ensure your transit authority can achieve this transition while maintaining client needs and without breaking the bank.
Quester Tangent was one of the first passenger train technology specialists to adopt the Ethernet standard. Click here to learn more about our integrated, Ethernet-enabled Trainwise TCMS and PIS, and our Fleetwise enterprise fleet management solutions for transit authorities and operators.