Private 5G Rail Is Outrunning the Standard Built to Define It

Quick Answer: Private 5G rail networks are becoming the delivery mechanism for FRMCS, the 5G-based standard built to replace GSM-R, and FRMCS has just moved from specification to shipping hardware. Comba began sampling n101-band radios purpose-built for FRMCS in July 2026, following Nokia’s first commercial 1900 MHz deployment on a Deutsche Bahn test track in 2025. In the United States, two major transit systems are separately replacing legacy signaling with 5G Communication-Based Train Control over private 5G, on entirely different spectrum. Neither project is a single deployment. FRMCS is designed to run alongside GSM-R for years, and that coexistence window is when systems integrators should build expertise and bill hours now, well ahead of any commercial go-live date.

More than 210,000 kilometers of railway worldwide still rely on GSM-R (Global System for Mobile Communications, Railway) for signaling and voice communication, a system built on second-generation mobile technology more than two decades ago, according to the International Union of Railways (UIC). In Europe alone, over 130,000 kilometers of track carry roughly 90,000 activated cab radios, all leaning on architecture that predates the smartphone.

For most of the last decade, the story of what replaces GSM-R lived almost entirely in slide decks. FRMCS has existed mostly as paperwork, user requirements documents, spectrum allocations, and standards-working groups. Operators nodded along at conferences. Vendors published roadmaps. Very little actually shipped.

That changed this year. Hardware built specifically for FRMCS started sampling. A test track in Germany has been running commercial 5G radio equipment for over a year. And on the other side of the world, two US metro systems began tearing out train control gear that has run traffic since before most of today’s riders were born.

The specification is finally becoming infrastructure, and the shift to private 5G rail is longer, messier, and more lucrative for the integrators involved than a typical upgrade cycle.

GSM-R Isn’t Failing. It’s Just Running Out of Runway.

GSM-R still works. It was never a bad system. For more than two decades, it has done what a voice-first, 2G-based radio network should do for train drivers, control centers, and trackside staff, reliably and safely. What it cannot do is support the modern rail operations that increasingly need it.

The Future Railway Mobile Communication System, FRMCS, is the standard that the International Union of Railways designed as GSM-R’s replacement, and it is built on a different foundation entirely. GSM-R runs on narrowband, circuit-switched 2G technology. FRMCS is specified as a full 5G Standalone architecture, with its own dedicated spectrum: a paired band around 900 MHz, known as n100, and a dedicated unpaired band at 1900-1910 MHz, known as n101. It carries mission-critical voice, data, and video over the same network and is built to support automated train operation, a capability GSM-R was never designed for.

UIC projects that GSM-R will become obsolete around 2030, as the hardware and components it depends on age out of production and vendor support. That deadline forces rail operators worldwide to plan a migration, even if FRMCS is not yet fully mature.

Ericsson’s own guidance to rail operators makes the shift concrete. FRMCS moves communications planning from a coverage-and-frequency mindset to a service-oriented one, where quality of service has to be engineered around specific applications, video, control data, voice, at speeds exceeding 300 km/h, a genuinely different discipline most rail engineering teams have not had to practice before.

FRMCS is also deliberately designed to run alongside GSM-R for years rather than replacing it in a single cutover, allowing operators to migrate individual lines on their own schedule, prioritized by traffic density, safety criticality, or how close existing hardware is to failure, without breaking the interoperability the wider network depends on. The result is a multi-year program, not a single cutover.

The Hardware Behind Private 5G Rail Just Showed Up

For years, FRMCS conversations took place almost entirely within standards bodies and pilot labs. The pace has picked up quickly.

In March 2025, Ericsson and Qualcomm completed the first interoperability test on the n101 band, running a purpose-built 5G radio prototype against a commercial modem chipset on FRMCS’s dedicated 1900 MHz spectrum. Six months later, Nokia’s Deutsche Bahn deployment put Europe’s first commercial 5G railway network on a live test track in Germany’s Ore Mountains, running on dedicated railway spectrum.

Then, in July 2026, Comba Telecom announced it had begun sampling a new line of compact private 5G radios, including a variant built specifically for the n101 band and FRMCS rail applications, sized for space-constrained enterprise and transportation deployments. That progression, from interoperability test to commercial pilot to sampling hardware from a mainstream vendor, is what real hardware maturity looks like.

AI is part of why this capacity matters. FRMCS’s bandwidth does more than clear up voice calls between drivers and control centers. It makes AI-driven rail applications viable at scale. Guangzhou Metro’s hybrid public-private 5G network has cut maintenance costs by 20% using 5G-enabled digital perception that automatically identifies waterlogging and other track hazards in real time, exactly the kind of continuous, high-bandwidth sensor traffic FRMCS’s dedicated spectrum was built to carry.

The same theme comes up in a conversation with PrivateLTEand5G, where Icomera’s Chintan Fafadia discussed how next-generation wireless, including 5G, is enabling new connectivity possibilities for both passengers and transportation operators alike.

Queensland Rail’s rollout shows the same logic at work as it moves into contracted delivery ahead of a hard deadline. In July 2026, Ericsson, working with UGL Transport and Frequentis, was selected to deliver a 5G-enabled Digital Radio System supporting European Train Control System (ETCS) Level 2 signaling.

The contract is part of Stage 1 of Queensland’s ETCS rail rollout, the Queensland Government’s rail infrastructure program connecting Brisbane and the Sunshine Coast ahead of the 2032 Olympic and Paralympic Games. It’s a live example of FRMCS-aligned private 5G reaching procurement before the standard itself is finalized.

PRO TIP: Vet the Band, Not Just the BrochureBefore quoting FRMCS-branded hardware for a pilot, confirm three things directly with the vendor: which band and duplex mode the radio supports, since n100 FDD and n101 TDD are not interchangeable, whether the unit has passed third-party interoperability testing rather than only internal bench testing, and whether “sampling” means engineering units still subject to change or production-track hardware. FRMCS branding is being applied loosely across the vendor landscape, and the gap between a marketing claim and deployable equipment is wide.

The US Isn’t Waiting for FRMCS, and That’s the Point

While Europe works through FRMCS’s standards process, US transit systems are running a parallel version of this private 5G rail migration, on a different spectrum and under different rules.

At IWCE 2026 in March, a panel confirmed that two major US metropolitan transit systems are currently undertaking significant projects to replace decades-old signaling on their subway networks with modern 5G Communication-Based Train Control (CBTC), delivered over private 5G networks. The goal is what drives FRMCS in Europe, too, allowing trains to run closer together safely, increasing capacity and cutting wait times, without relying on radio technology that is decades past its design life.

Precision matters here because these are not the same standard. FRMCS is a specific, UIC-defined global framework built on dedicated European railway spectrum, n100 and n101. US passenger and freight rail has instead relied for years on a separate system, Positive Train Control, operating in the 220 MHz band and licensed through the PTC-220 consortium under FCC rules. The private 5G CBTC upgrades discussed at IWCE sit outside both frameworks, urban metro modernization projects built on whatever spectrum the transit agency selects, not a US adoption of FRMCS itself.

For systems integrators, that distinction carries real commercial weight. FRMCS expertise, spectrum planning across n100 and n101, and coexistence engineering with GSM-R are a European and increasingly global rail opportunity. Private 5G CBTC expertise, architecture, radio planning, and safety certification inside US transit tunnels and yards is a separate opportunity that doesn’t need a European standards body to finish its work first. Boldyn Networks’ 2025 Airspan and Druid deployment for a major European railway’s maintenance and operational facilities shows how differently these two markets are structured, built around Open RAN infrastructure and a dedicated 5G core rather than a CBTC signaling upgrade.

What Actually Changes When a Railway Moves Off GSM-R

The scale of this shift in private 5G rail is easiest to see side by side.

Dimension	GSM-R	FRMCS
Architecture	2G, circuit-switched, voice-first	5G Standalone, IP-based, data and video native
Spectrum	Narrowband, shared legacy allocations	Dedicated bands: n100 (900 MHz) and n101 (1900 MHz)
Core use cases	Voice, basic ETCS signaling data	Mission-critical voice, data, video, and automated train operation
Status in 2026	In service, approaching the end of life around 2030	Trials underway, hardware sampling, phased rollout beginning

What the table doesn’t fully capture is that this is not a radio swap scheduled over a maintenance weekend. It is an architecture change, from circuit-switched 2G to a 5G Standalone network with its own core, spectrum plan, and application layer. FRMCS migration functions as a systems integration program rather than a procurement line item because of that shift, and early movers like Deutsche Bahn and Queensland Rail are treating it that way, with dedicated partners for radio, core, and rail engineering rather than a single vendor covering everything.

The Money Is in the Migration, Not the Milestone

This is the part of the private 5G rail story that coverage focused on go-live dates tends to miss.

FRMCS’s coexistence design, running alongside GSM-R for years, is the actual business opportunity for systems integrators. A phased migration requires interference coordination between two live networks sharing overlapping geography, a cutover sequence prioritized by traffic density or hardware age, parallel testing environments, and staff retrained on an architecture most rail teams have never operated.

That work doesn’t wait for FRMCS to be finished or fully commercial. It starts the moment an operator commits to a migration timeline, and several have already done so. The coexistence period, likely to run for most of the next decade, is billable, technically demanding work that most generalist telecom integrators aren’t yet positioned to do.

This is also where the platform’s core question gets a real answer for this vertical. What does an SI leader in rail see here that generic coverage doesn’t solve? The revenue in FRMCS doesn’t sit in the eventual commercial rollout, which typically goes to whoever won the original vendor contract. It sits between interference planning, phased testing, and coexistence engineering, work that requires understanding what’s ending and what’s replacing it at the same time.

PRO TIP: Price the Coexistence Window, Not Just Go-LiveStructure FRMCS proposals around the years-long period when GSM-R and FRMCS run side by side, not around a single go-live milestone. Interference coordination, phased line-by-line testing, and staff training on 5G Standalone architecture are billable long before an operator sees returns from automated train operation or predictive maintenance. Price that coexistence work as its own engagement rather than folding it into the eventual contract.

STAY AHEAD OF THIS MIGRATIONStaying ahead of private 5G rail timing and coexistence windows, before your competitors do, is what this vertical series tracks as it develops. Subscribe to follow it.

Where Does This Leave You?

If you’re a vendor or systems integrator working in private 5G rail, the real work right now sits in the multi-year coexistence engineering underneath the eventual FRMCS commercial rollout, not in the rollout itself. Build 5G Standalone and mission-critical spectrum expertise ahead of the broader market. Get in front of the private 5G CBTC procurement cycle already underway in US metro transit, since it doesn’t need FRMCS to reach commercial maturity first. And if you want visibility with the operators and vendors shaping this vertical specifically, the Executive Voice Program and Partner With Us are built for that kind of positioning.

If you’re planning your own move to private 5G rail, start from an honest premise. There is no single hard deadline forcing your hand. GSM-R’s projected 2030 obsolescence is a runway, and that runway is exactly why waiting is often the more expensive choice. Map your network’s actual coverage gaps and data demands against what FRMCS or private 5G CBTC would require to support, rather than assuming your existing radio footprint translates directly to the new architecture. A wireless self-audit is the fastest way to honestly build that baseline, and it’s worth doing before any vendor conversation begins.

Frequently Asked Questions

The questions below come up whenever this migration is discussed with the people actually responsible for building or operating it.

Is FRMCS relevant to private 5G rail in the US, or is this strictly a European standard?

FRMCS itself is a UIC-defined standard built around European spectrum allocations, n100 and n101, and it isn’t the framework governing US passenger or freight signaling today. US rail safety systems run on Positive Train Control in the 220 MHz band, under a separate FCC licensing structure. The pressure behind both, moving legacy 2G-era rail communication onto 5G Standalone architecture, is a global trend, and the private 5G CBTC upgrades in US metro transit are a parallel expression of it.

Comba announced its sampling n101 radios. Does that mean FRMCS-ready hardware is commercially available?

Not yet. Sampling means Comba is supplying early production units to select customers for testing and validation, not the broad availability or certification a mission-critical deployment requires. It’s a meaningful signal that FRMCS hardware has moved beyond pure specification work, building on earlier interoperability testing by Ericsson and Qualcomm, as well as Nokia’s pilot network with Deutsche Bahn. Full commercial availability at scale is still likely a year or more out.

What does running GSM-R and FRMCS in parallel require operationally?

It requires the two networks to coexist geographically without interfering with each other, since GSM-R still occupies part of the 900 MHz spectrum that FRMCS will eventually use. Operators need a phased cutover plan that migrates lines in sequence, prioritized by traffic density, safety criticality, or hardware age. It also requires parallel testing environments to validate new infrastructure without disrupting live train movements, as well as staff who can operate both systems throughout the transition.

What FRMCS-specific skills should an SI build right now, before large-scale rollouts start?

Spectrum and interference planning across the n100 and n101 bands is the most immediately useful skill, needed at every phase of a migration. Familiarity with 5G Standalone core architecture matters just as much, since FRMCS isn’t an evolution of GSM-R’s circuit-switched design but a different network to operate. SIs should also build experience with phased, coexistence-based cutover planning, migrating live, safety-critical infrastructure without downtime, work that differs from a greenfield deployment, and is where most near-term billable work will sit.