For years, rail passengers across the UK have faced the same frustration: patchy Wi-Fi, unreliable mobile coverage, and long blackouts between major cities. Despite billions invested in modern rolling stock and infrastructure, digital connectivity on Britain’s railways still lags behind the expectations of modern travellers.
A recent Streetwave report testing mobile data performance between London and Sheffield illustrates the scale of the problem. Their research revealed that even on one of England’s busiest intercity routes, mobile signal strength and download speeds were far below what’s needed to keep passengers and rail operators connected.
This isn’t just an inconvenience for passengers streaming Netflix or joining work calls, it’s a symptom of an industry-wide issue that impacts efficiency, safety, and reputation.
The Mobile Connectivity breakdown
Streetwave’s findings paint a stark picture of just how inconsistent mobile data coverage is along UK rail lines. Across all four major operators, essential coverage (the percentage of the route with a stable, usable signal) was alarmingly low
- Vodafone: 29%
- EE: 26%
- Three UK: 19%
- O2: 17%
That means for over two-thirds of the journey, none of the major networks could sustain a stable data connection.
The situation worsens when looking at actual speeds. Median download speeds recorded by Streetwave show just how far short mobile data falls of passenger expectations:
- EE: 11.2 Mbps
- Three UK: 3.7 Mbps
- Vodafone: 3.5 Mbps
- O2: 1.9 Mbps
In real terms, that’s barely enough to load a webpage — let alone support real-time applications, video calls, or streaming. Between rural segments, tunnels, and viaducts, the signal simply drops away, leaving long dead zones where passengers are cut off entirely.
This isn’t an occasional dropout; it’s a structural connectivity gap that affects every service, every day. The result? Trains operating in digital isolation, disconnected from the networks that modern passengers and rail operators depend on.
The real-world impact: passengers and operators left in the dark
When mobile connectivity collapses mid-journey, it doesn’t just affect entertainment, it disrupts how the railway functions.
For passengers, it means frustration and lost productivity. Business travellers can’t join video calls, commuters can’t check live journey updates or emails, and leisure travellers can’t access digital ticketing or mobile payments. In an age where travellers expect the same online experience they have at home or in the office, this digital dead zone makes rail feel dated and unreliable.
For operators, the consequences go much deeper. Modern trains rely on connectivity for critical operations — from real-time diagnostics and CCTV backhaul to crew communications, passenger information systems, and predictive maintenance. When networks fail, data gaps emerge that can compromise safety, delay repairs, and increase operating costs. Without visibility across their fleet, operators are essentially running blind in key areas of performance monitoring.
This isn’t a one-off inconvenience; it’s a systemic problem that limits innovation, undermines digital transformation, and ultimately impacts customer satisfaction.
Why the problem persists
The rail industry has been wrestling with connectivity challenges for decades. Previous attempts to fix the issue such as like cellular repeaters, multi-network SIMs, and 4G/5G boosters have made modest improvements but failed to provide consistent coverage.
The reasons are simple: mobile networks are designed for stationary or slow-moving users, not high-speed trains hurtling through rural terrain at 125 mph. Constant handovers between cell towers, physical obstructions, and limited backhaul capacity create unavoidable dead zones. Building terrestrial infrastructure for every kilometre of track would cost billions and still leave gaps.
As a result, even as the rest of the transport sector embraces digitisation, UK rail connectivity remains stuck in the past.
How clarus and starlink are changing the picture
Recognising the need for a step change, Clarus Networks, in partnership with ScotRail, has delivered the world’s first rail-certified Starlink deployment — a major leap forward for onboard connectivity.
The solution uses SpaceX’s low Earth orbit (LEO) satellite network to provide stable, high-speed, low-latency internet to moving trains, even in the most remote areas. The system has achieved full rail certification under EN50155, EN50121, and EN45545, confirming compliance with rail safety, fire, and electromagnetic standards.
The deployment, installed across six Class 158 trains operating on rural Scottish routes, uses Starlink Gen 3 Performance Dishes combined with rail-certified Wi-Fi tiles to distribute signal throughout the carriages. This allows continuous connectivity across areas that were previously blackouts for mobile service — reducing dropouts, maintaining throughput, and bringing true broadband to the rails.
Rail-Certified Starlink: Meeting the Rigours of rail
Earlier this year, In partnership with ScotRail, we delivered the world’s first rail-certified Starlink deployment, engineered to perform under the toughest rail conditions. This isn’t a retrofit, this system has passed full certification to EN50155, EN50121, and EN45545, confirming its suitability for use in rail environments in terms of electrical safety, electromagnetic compatibility, fire protection, and robustness to vibration, shock, temperature swings, and weather exposure.
Our system couples this certified Starlink terminal which has been rigorously tested to rail standards with internal rail-approved distribution tiles inside the train. The antenna maintains a stable satellite link even across changing terrains and signal shadows, while carriage-level tiling ensures consistent bandwidth delivery to passengers and onboard systems. Because it bypasses ground-based network infrastructure entirely, it avoids the handover failures and coverage gaps that mobile networks routinely suffer on fast-moving rail corridors.
Looking ahead: building a connected future for rail
Streetwave’s test on the London–Sheffield line exposes a national challenge, but also an opportunity. Reliable connectivity is no longer a passenger perk; it’s a core requirement for modern rail. As the UK pushes towards decarbonisation and smarter mobility, digital infrastructure will be just as vital as track and rolling stock.
The partnership between Clarus and ScotRail shows what’s possible. By integrating satellite technology into rail operations, we’re bridging the gap mobile networks can’t fill and setting a new benchmark for connectivity on the move.
In the years ahead, our vision is to extend this capability beyond Scotland, across the UK and Europe, ensuring trains stay connected from platform to platform, no matter the landscape. Because in the future of rail, being online isn’t optional; it’s essential.
