High speed train – Infrastructure

Note: For educational purpose only. This page is meant purely as a documentation tool and has no legal effect. It is not a substitute for the official page of the operating company, manufacturer or official institutions. It cannot be used for staff training, which is the responsibility of approved institutions and companies.

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Site map High Speed Railways

1 – Overview → 2 – Infrastructure → 3 – Rolling Stock → 4 – Train services → 5 – Economics & Post evaluation

Key words

This section explain:  
• Geography – Topology
• Interoperability
• Signalling
• HSR stations, flow and architecture

Geography

Due to continental European topology, with flat terrain, low and medium mountain areas and the Alps – the high mountain region ranging from Austria in the east via Germany and Switzerland to France in the west and dividing northern and southern Europe – a considerable number of tunnels and high rising, as well as wide spanning, bridges are required to accommodate HSR section alignment needs. The constructing of the Swiss Lötschberg, Ceneri and Gotthard base tunnels, as well as the Austrian Brenner base tunnel, are technical challenges which require multi-billion euros and are financed by the public and private sectors to enable an integrated European railway network.

Most countries worldwide with HSR network have decided to develop new HSR lines exclusively dedicated to high-speed trains (Japan). However, some countries have mixed HSR where high-speed trains use dedicated lines and upgraded conventional tracks (France); some countries have fully mixed railway network where most of the tracks are used by all passenger and freight trains (Germany) whilst there is one more type of HSR where the high-speed track is used by high-speed trains and conventional trains equipped with a gauge-changing system (Spain).

Germany had some problems of constructing HSR caused by topographical specific issues dominated by mountainous terrains. Germany’s railway infrastructure was upgraded instead of building new dedicated lines only for high-speed trains and it serves passenger and freight traffic. It is a multi-purpose railway network. 

HSR in Italy is integrated with conventional lines. This increases railway network capacity, increases the effects of HSR and prevents the deterioration of the conventional services, but it affects the reliability of services. In Italy.

In Taïwan, THSR network is that almost 90% of the route is running either in tunnels or raised viaducts due to topographical features such as steep gradients in the terrain. With a maximum speed of THSR up to 190 mph and with the increasing stresses on the brakes and wheels and on infrastructure, there is a need for additional requirements for maintenance to provide a high level of performance.

Today, most European HSR services operate with trains capable of maximum speeds in the range of 280-300 km per hour.

Interoperability – The Technical Challenge

Implementing an HSR system in Europe is not just about introducing powerful rolling stock. The national railway systems in Europe were developed quite differently in various aspects. While three different track gauges exist across Europe (Spain, Portugal, Ireland, Finland and the three Baltic states), it becomes significantly more complex in regard to national signaling systems, where as many as 20 different systems are in operation in Europe.

In terms of infrastructure, interoperability in Europe has involved adopting a standard gauge that allows trains to pass each other at speeds of 300 or 350 km/h without breaking the windows. This has led to the choice of a track gauge that is wider than that found on conventional tracks. This also limited the width of the vehicles, which could not be wider anyway, as it would then have been impossible to accommodate these trains in existing stations in Europe.

As an example, we can view this table comparing the different technical parameters of four countries. Please note that these figures come from the 1990s, which explains why the last row shows rolling stock that is hardly used today, particularly in Japan.

While rolling stock has evolved since then, high-speed infrastructure has remained largely unchanged, apart from signalling. The Shinkansen dates back to 1964, the French TGV is over 40 years old, while the German ICE and Spanish AVE are now over 30 years old.

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Asia
The Japanese and Taiwanese Shinkansen trains, on the other hand, are wider than European trains, but in both cases they run on dedicated tracks and stations. Interoperability is therefore not necessary in these countries.

The design of high-speed tracks determines the width of the platform: tracks are no longer built as they were in the 19th century. What is known as the ‘railway domain’ can be 20, 30 or 40 metres wide, depending on the circumstances. Access tracks for staff are also mandatory on both sides, something that was not done in the past.

All in all, high-speed tracks cover 50, 80 or 100 km and take up much more space than old conventional tracks. This has an impact on construction costs, but we must not forget that once a line is built, it has an indefinite lifespan and today’s expenses will not be the expenses tomorrow, apart from maintenance costs.

However, there is one area in Europe where a major effort towards interoperability was necessary: signalling.

Signalling

The electrotechnical choices made in the 1950s – such as train detection – cannot be changed in a matter of days, as this would require modifying all the equipment on all trains, which no incumbent operator is capable of doing.

In addition, although high-speed trains are considered ‘modern’, those in Europe must reach existing stations whose tracks still use still older technology. This is not the case in Asia, where HSR tracks have been created in their entirety in existing stations, if not in new stations as in Taiwan or China.

High speed, which no longer allows for the observation of lateral signals, makes it necessary to install on board trains a screen that displays movement orders and speeds as the train advances. This technology did not exist in the 1950s–1960s and nowadays relies on computer systems.

The French TGV had shown the way as early as the 1970s and 80s, but with the technologies available at that time. But how to cross borders?  As the Germans and Italians developped their own in-house technology, it was decided in the 1990s to create the UNISIG association, bringing together several companies specializing in signaling in order to create one single signalling system. From this association emerged a set of standards that could suit everyone. This standard, called ERTMS/ETCS, became legally binding thanks to legislative action by the European Union.

The European Technical Specifications for Interoperability (TSIs) provided the framework for the development of design for all project elements. The TSIs were developed to ensure interoperability between rolling stock and the railroad systems of all countries within the European Union.

These TSIs do not concern only signalling but all the main parameters of the high-speed system as a whole. The TSIs have been mandatory since 2006 for any new high-speed line, even without crossing borders in Europe. Over time, ERTMS/ETCS has become a global standard, although there is no obligation to use it.

ERTMS uses Global System for Mobile Communications – Railway (GSM-R) which incorporates frequencies in the high 800 and low 900 MHz range. GSM-R has been specifically assigned for railway use (hence the R in the acronym) throughout Europe and other countries in the world.

The choice of frequencies was something decided at the highest global level within the ITU (International Telecommunication Union). This organization allocates bands to the various services (mobile, broadcasting, satellite, etc.) and proposes global plans. The World Radiocommunication Conferences (WRC) are where these decisions are made between member states, and according to experts, the railway sector has had the greatest difficulty in making its case against giant sectors such as merchant shipping, aviation, or even emergency services.

New technology for signalling
FRMCS (Future Railway Mobile Communication System) is the new global communication standard set to replace GSM-R, which has been used in railways for over two decades. GSM-R, based on 2G technology, is becoming obsolete, with limited capacity and support. FRMCS, developed under the UIC and 3GPP standards, will use modern 4G/5G technology to provide faster, more reliable, and more secure communications for train control, signaling, and operations. It supports higher data rates, interoperability between countries, and integration with emerging railway automation systems. Deployment is planned progressively to ensure continuity while transitioning from GSM-R before its network support ends.

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Stations

The stations of a high-speed rail network could be considered as something separate, but in reality, it all depends on what is called the “network effect.” When Japan inaugurated its first new line in 1964, everything was new: the line, the track gauge, and the civil engineering. Tokyo’s historic station, designed by Tatsuno Kingo and opened in 1914, retained its original Marunouchi-side building even after the arrival of the Shinkansen. In the absence of available ground space, the chosen solution was to stack the Shinkansen tracks above the existing entrance halls and ticket offices.

In France, the original idea—still upheld today—was not to make the TGV a special train with dedicated stations set apart from the rest of the network. It was therefore decided that the French TGV would arrive in existing stations, or very nearly so. While the TGV was present from the very beginning in 1981 at Paris-Gare de Lyon as well as Lyon-Perrache, it was decided in 1983 to close the old Lyon-Brotteaux station in favor of Lyon-Part-Dieu, located 700 meters away on the site of a former freight station.

Although all TGVs in France now arrive at historic stations, the SNCF nevertheless built new stations outside cities in many locations. Germany and Italy have followed this approach much less, in contrast to Taiwan, which has made extensive use of it.

Two major characteristics are evident when welcoming high-speed trains, regardless of the station chosen:

• on the one hand, the planned length of these trains in normal operation;
• on the other hand, passenger flow management: separate arrivals/departures? Screening on departure? What about luggage?

In Europe, the dimensions of the French TGV show a train length of 200 metres. By coupling two trains, a length of 400 metres is obtained. This dimension was chosen and incorporated into European TSIs as a maximum not to be exceeded. When it was launched in November 1994, the first TGV Eurostar TMST Class 375 (GEC-Alsthom) was exactly 375 metres long, consisting of two separable half-trains. This measurement had an impact on the construction of the Channel Tunnel itself, in terms of the connecting branches between the tubes.

In Germany, the various ICE series have never exceeded 400 m, and the longest of them, the ICE 4, is currently 374 m long with 13 carriages. In Italy, Trenitalia’s ETR 400 Frecciarossa is 202 m long, which would make it 404 m + the gap between trains.

All this to say that in stations serving high-speed trains, a 400-metre platform is the norm. It should be noted that the length of the platforms has no impact on the track gauge: 1,435 mm in Europe and even in Asia, it makes no difference.

In term of flow, the long HST platforms offer a hidden benefit: passengers are distributed over a larger area, significantly reducing passenger density. Train capacity is relatively low; comfortable HST trains will seat no more than 1,000 passengers so the long platforms will provide ample space for boarding and alighting.

By contrast, a typical MRT vehicle may squeeze 3,000 to 4,000 passengers into a vehicle less than half the HST length. Side platform configuration, most commonly employed for CHST stations, provides clear separation of northbound and southbound passengers on platforms, further contributing to passenger comfort.

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Flow
Flow management took a particular turn in Spain, a country that faced significant risks of terrorist attacks in the 1990s (demands for autonomy of the Basque Country). As early as 1992, the Madrid-Atocha (rebuilt), Cordoba and Seville (also reconfigured) stations adopted an airline-style check-in procedure for security purposes, with baggage X-ray screening and ticket verification before boarding.

Subsequently, stations on other high-speed lines retained the check-in principle, including Barcelona-Sants, Valencia, Malaga and many others. This check-in principle obviously requires more space, particularly in existing stations.

Check-in was also applied at Paris-Nord, Brussels-Midi and London-Waterloo when the Eurostar service was launched, for obvious customs reasons, as the United Kingdom is not a member of the Schengen area. These three stations had to design an entire dedicated space: at Brussels-Midi, the former postal and small parcel facilities have been replaced by an entire terminal designed solely for Eurostar, with 400-metre platforms.

Since 2007, Eurostar trains have been welcomed at London St Pancras in a Great Britain that has now left the European Union (2021). Customs formalities remain in place – and have even been tightened – while the possible arrival of one or more other operators is on the horizon, sparking debate about how to manage passenger flows at St Pancras station, which has been superbly renovated and features 400-metre platforms under a magnificent canopy.

Architecture
High-speed rail (HSR) stations in France, Italy, Taiwan, and China balance architectural expression with operational efficiency. In France, AREP designs stations like Avignon TGV or the Calatrava’s Lyon-Airport station focusing on functionality, passenger comfort, and climate adaptation, blending practicality with elegant forms. Italy’s Reggio Emilia Mediopadana station by Santiago Calatrava showcases iconic, landmark architecture that also ensures effective operations.

Taiwan’s stations, designed by Kris Yao, emphasize integration with local environment and culture, using forms like curved roofs to address wind conditions while enhancing passenger experience.

In China, MAD Architects’ Jiaxing station merges modern facilities with historic preservation, balancing heritage and contemporary needs. Overall, these designs reflect a spectrum—from pragmatic and context-sensitive to bold and symbolic—while prioritizing smooth passenger flow, accessibility, and environmental harmony alongside striking architectural identity. The goal is to create stations that serve as efficient transport hubs and urban landmarks.

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