Italy’s first fully integrated earthquake early warning system for high-speed rail between Rome and Naples

Researchers say Italy’s first fully integrated earthquake early warning system for high-speed rail can deliver targeted alerts in as little as three to ten seconds, while correctly anticipating shaking in more than 90% of cases.

This shifts the way seismic risk is handled on fast rail corridors, because it focuses disruption on the precise section of line most likely to be hit rather than slowing everything.

Along the corridor

Across roughly 200 km of railway between Rome and Naples, a purpose-built chain of buried sensors keeps watch over one of Italy’s most seismically active routes.

Working from these continuous streams, engineers at the University of Naples Federico II (UNINA) showed that the earliest arriving motion can be turned into immediate, operational choices about where trains should reduce speed or stop.

As additional parts of the seismic signal reach stations closer to the event, the platform tightens its estimates and can resize the affected track section within seconds.

That progressively updated, segment-by-segment strategy reduces wider knock-on delays, but it relies on interpreting incomplete early information quickly - shaping how the system trades raw speed against confidence.

Why seconds matter

Because high-speed services move so quickly, even a short lead time can be enough to prevent a train entering track that is about to be damaged.

When the first faint seismic arrivals - P waves - are detected by the sensors, the strongest shaking has not yet reached the corridor.

That small time gap is what allows railway control to act before the most damaging motion arrives.

On a busy passenger high-speed line, a handful of seconds is not much, but it can determine which trains are exposed to the compromised section.

Reading the first pulse

At each installation, buried accelerometers (ground-motion sensors) are used to capture the initial tremor and transmit measurements straight away.

At five sites, additional sensors sit 20 m underground, where reduced surface disturbance helps the earthquake signal stand out.

A dedicated communications network carries the readings by fibre optics to Naples, where Rome–Naples high-speed line Rete Ferroviaria Italiana (RFI) servers are set up to minimise latency that would otherwise consume the warning window.

These design decisions matter because early warning hinges on delay - not on having perfect detail in the first moment.

Filtering seismic noise

With hundreds of trains passing daily, rail-side instruments constantly record vibration, so the software’s first task is deciding whether a jolt is actually seismic.

To do this, its filter considers both amplitude and frequency content, since train-induced vibrations typically contain more high-frequency energy than the start of an earthquake.

It needs only 1.5 seconds of signal for this initial screening, a crucial saving on a line where trains cover distance rapidly.

False alarms can still happen, but removing some train noise early helps avoid stopping regular services for non-seismic events.

Mapping danger zones

Once a quake is accepted, the system predicts peak ground acceleration - the strongest shaking expected at each instrumented point.

That estimate is built from the first motion and then refreshed every second as additional wave energy reaches nearby stations.

Rather than suspending the whole route, the software outlines an alerted segment and applies a safety buffer at either end.

Because operational railway risk is driven by where shaking exceeds a set threshold, this evolving segment map is more important than any single estimate of the epicentre.

Sending brakes the message

On the Rome–Naples high-speed line, RFI worked with researchers to implement the warning so that seismic assessments translate directly into rail control actions.

When thresholds are exceeded, control systems command either a reduction in speed or a complete stop within the impacted stretch.

“We have developed, in collaboration with RFI, the first warning system for high-speed trains capable of detecting in advance the seismic waves generated by earthquakes that could affect the railway network,” said Aldo Zollo, professor of seismology at UNINA.

Once shaking has finished, operators check the route and can bring unaffected sections back into service sooner than would be possible under a corridor-wide shutdown.

Measuring real performance

To evaluate the platform under demanding conditions, the team replayed hundreds of earthquake recordings and superimposed many of them with train noise.

In these simulations, initial alerts were issued within three to ten seconds, and shaking was correctly identified in more than 90% of cases.

After a further five seconds, accuracy improved again because the extra signal enables the software to refine expected shaking intensity at each site.

Configurations that demanded higher certainty delayed the first alert without delivering much additional benefit - a trade-off with real consequences on operating railways.

How much track at risk

For the more frequent nearby earthquakes, the threatened section would typically be only about 9.7 km of track, rather than the whole corridor.

Using two months of train movements, the researchers found that, in these more likely scenarios, most services would remain outside the alerted zone.

An alerted segment of around 100 km appears mainly for rare, large earthquakes close to the route, with return periods of roughly 2,000 years.

By contrast, the more common moderate events near the railway would usually isolate a far shorter length, allowing most operations to remain manageable.

Beyond one railway

The underlying platform was designed so it can be integrated with other lines, provided their seismic data can be delivered in real time.

Connecting across routes would also improve earthquake location, because a broader, sparser network can constrain position better than a single line on its own.

This becomes important for future shake maps - rapid estimates of expected shaking - which could help inspection teams prioritise checks within minutes.

While the system can be scaled, the study also indicates that cross-line integration and denser sensor coverage still lead to better decisions.

Smarter rail safety

Italy’s rail warning approach turns a few seconds of seismological information into a usable safety margin for one of the country’s fastest routes.

Its key advantage is not stopping every train everywhere, but stopping the right trains early enough to avoid more serious outcomes.