The Evolution of Layout Command Control: From Proprietary Chaos to Open Standards

For decades, model railroaders have faced a fundamental challenge: how to control the countless accessories, signals, turnouts, and detection systems that bring their layouts to life. While Digital Command Control (DCC) revolutionized locomotive control in the 1990s, layout accessory control remained a fragmented landscape of proprietary systems that rarely worked together. The story of how Layout Command Control (LCC) emerged to solve this problem is one of collaboration, innovation, and a commitment to open standards that benefits the entire hobby.

The Problem: A Patchwork of Proprietary Solutions

Before LCC, model railroaders who wanted to automate their layouts had to navigate a confusing maze of incompatible systems. LocoNet from Digitrax, NCE's Cab Bus, XpressNet from Lenz, C/MRI, and numerous other proprietary protocols each offered solutions for specific manufacturers' products—but they couldn't talk to each other. If you invested in one manufacturer's ecosystem, you were essentially locked in. Want to add a control panel from a different manufacturer? Too bad. Need a signal system that your current vendor doesn't offer? You'd have to run parallel systems or start over.

These proprietary systems also suffered from technical limitations. Many were one-way communication systems, making feedback and status reporting difficult or impossible. They were often designed with the technology of the 1980s and 1990s, struggling to keep pace with the increasingly sophisticated demands of modern layouts. DCC itself, while excellent for locomotive control, was never designed to handle the heavy accessory control traffic that large layouts require—it's a one-directional system primarily optimized for repetitive mobile decoder commands.

2008: The NMRA Takes Action

Recognizing this growing problem, the National Model Railroad Association (NMRA) formally began work in 2008 to develop a standardized control bus. The goal was ambitious: create an open standard that would manage and control all layout devices independent of train control—one that would work across manufacturers, scale from simple home layouts to massive modular club installations, and remain relevant for decades to come.

This initiative, initially called NMRAnet, would become Standard 9.7 in the NMRA's documentation system. But the NMRA recognized early on that developing such a comprehensive standard wasn't something a small committee could accomplish alone. The complexity of creating protocols, writing code, developing reference implementations, and thinking through countless use cases—from a novice connecting two boards to massive museum layouts—required a different approach.

Enter OpenLCB: Open Source Innovation

Around the same time, a group of dedicated volunteers formed what became known as OpenLCB—the Open Layout Control Bus project. This open-source development effort brought together hobbyists, engineers, and manufacturers who shared a vision: create a modern, flexible, future-proof control system for model railroads that anyone could implement without licensing fees or proprietary restrictions.

The OpenLCB group approached the problem methodically, developing their protocols in public and basing their work on extensive use cases that ranged from simple two-board setups to complex multi-club modular layouts. They chose the Controller Area Network (CAN) bus as their primary physical layer—the same robust, proven technology used in automotive applications—while designing the protocols to be "transport agnostic," meaning they could also work over Ethernet, WiFi, and other network technologies as layouts grew in size and complexity.

One of OpenLCB's most innovative concepts was the Producer/Consumer (P/C) model. Instead of devices needing to know about each other directly, they simply produce or consume "events"—abstract messages that can represent anything from "turnout 5 thrown" to "set lighting to evening mode." This elegant design allows incredible flexibility: one button can control dozens of devices, and you can add new equipment without reconfiguring existing nodes.

2011: The Partnership Forms

The breakthrough came in July 2011, when the NMRA Board of Directors made a crucial decision: they would base NMRAnet/S-9.7 on the OpenLCB designs. This represented a new model of standards development for the model railroad hobby—the NMRA would provide oversight, review, and official adoption of standards, while the OpenLCB group would continue their open-source development work creating the actual protocols and technical documentation.

In January 2021, this relationship was formalized through a Memorandum of Understanding (MOU) between the NMRA and OpenLCB. The MOU clearly delineated responsibilities: OpenLCB would develop standards and provide technical notes to support those standards, submitting them to the NMRA for review and comment by the membership. Once reviews were complete, the NMRA Board of Directors would adopt them as official NMRA Standards for Layout Command Control.

The Rebranding: From NMRAnet to LCC

Around 2015, the NMRA made an important branding decision. The standard, which had been called NMRAnet during development, was renamed Layout Command Control (LCC) to more clearly communicate its purpose. The name emphasizes that this is a control system specifically designed for model railroad layouts, working alongside (not replacing) DCC. The phrase "DCC on the track, LCC beside the track" became a common way to explain the complementary relationship between the two standards.

Standards Adoption and Evolution

The first LCC standards were adopted by the NMRA Board of Directors in 2012, focusing on the physical specifications of LCC as implemented on CAN. But the development didn't stop there. Each LCC standard is organized with a corresponding Technical Note that provides additional reasoning and implementation guidance—helping manufacturers understand not just the "what" but the "why" behind each specification.

Over the following years, additional standards were developed and adopted, covering:

Message protocols and event transport
Configuration and memory management
Datagram transport for larger data transfers
Firmware upgrade protocols
Broadcast time synchronization
And much more

The Latest Evolution: Train Control Integration

One of the most exciting recent developments came with the 2024-07-22 document set, which was adopted by the NMRA Board of Directors in January 2025. This latest evolution brings LCC into direct train control with protocols for:

Throttle-to-Train Communication: Bidirectional protocols allow throttles to communicate with trains (whether DCC locomotives controlled through a command station or future wireless trains) including speed control, function management, and emergency stop. Uniquely, the train can provide feedback about its actual speed and function states.

Train Search Protocol: A peer-to-peer system for finding and identifying trains on the network by address or cab number, working seamlessly whether trains are represented by a command station or connected directly via wireless communication.

Function Description Information: Trains can now tell throttles exactly what functions they support, including names, descriptions, and whether functions are momentary, toggle, or analog—enabling intelligent, train-specific user interfaces.

This means LCC is evolving beyond just "beside the track" control into a comprehensive system that can handle train control as well, offering a modern alternative or complement to traditional DCC command and control systems.

Commercial Reality: Products Hit the Market

While standards are important, they're only valuable if manufacturers implement them. Starting around 2016, commercial LCC products began appearing. Today, companies including TCS (Train Control Systems), RR-CirKits, and others offer:

Control boards for turnouts, signals, and I/O
LCC-compatible command stations
Wireless and wired throttles
Gateway devices connecting LCC to LocoNet, XpressNet, NCE, and other legacy systems
Software tools for configuration and operation

The ability to bridge LCC with legacy systems is particularly important—it means modelers can gradually adopt LCC without abandoning their existing investments, and can mix equipment from different manufacturers' ecosystems within a single unified network.

Looking Forward: Future-Proof by Design

One of OpenLCB's founding principles was to design for the next 20-25 years of model railroading. The protocols use deliberately large address spaces (48-bit Node IDs and 64-bit Event IDs) to ensure they'll never run out of capacity. The modular nature of LCC protocols means new capabilities can be added without breaking backward compatibility.

Current development work within OpenLCB includes:

Location services integration (RFID, RailCom readers)
Enhanced configuration tools and user interfaces
Expanded train control features
Additional gateway protocols

The open-source nature of the development means anyone can participate. The OpenLCB group maintains public documentation, reference implementations, and development forums where hobbyists, manufacturers, and engineers collaborate on the future of layout control.

The Success of Open Standards

The LCC story demonstrates the power of open standards developed collaboratively. By learning from DCC's 20-year history—both its successes and limitations—and by building on modern networking technology, LCC provides a foundation for layout control that's simultaneously simple enough for beginners and powerful enough for the largest modular layouts.

Where DCC once ended the era of dozens of incompatible train control systems, LCC is doing the same for layout accessory control. The difference? This time it's happening through a unique partnership between an open-source development community and the official standards organization, combining the innovation and agility of open development with the stability and industry acceptance of NMRA standards.

As LCC continues to gain adoption and manufacturers bring more products to market, model railroaders are discovering the benefits of a system designed for their needs: plug-and-play simplicity, manufacturer interoperability, bidirectional communication, and the confidence that their investment is built on standards that will serve the hobby for decades to come.

The Layout Command Store is proud to be part of this evolution, supporting both the LCC ecosystem and the open development process that makes it possible.

Want to learn more? Visit OpenLCB.org to see current development work, read technical documentation, and even participate in shaping the future of layout control. The NMRA's official LCC page at NMRA.org/lcc provides access to adopted standards and technical notes.