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Rail

More efforts needed
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About this report

From their peak in 2019, direct CO2 emissions from rail are not projected to increase beyond just over 100 Mt CO2. Over the past two decades, direct CO2 emissions from diesel rail operations increased through 2019 by less than 1% on average annually (electric rail, which accounts for about 80% of passenger rail activity and half of freight movements, does not release any direct CO2 emissions). To get on track with the Net Zero Emissions by 2050 Scenario, emissions will need to decline by about 6% annually, a goal which requires the electrification of diesel operations wherever viable, as well as blending biodiesel and implementing a wide range of other efficiency measures.

CO2 emissions

CO2 emissions from rail in the Net Zero Scenario, 2000-2030

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Urban rail networks such as metro and light rail can have significantly lower emissions than other motorised urban transport modes, especially private cars.

On a “well-to-wheels” (wing/wake) basis, rail emissions per passenger kilometre are currently on average around one-sixth those of air travel. Emissions from electrified passenger rail are even lower, particularly when powered by renewables or nuclear power.

European players are planning important investment in rail transport to make it more appealing to travellers, especially over short-haul flights. Expanding rail networks and their use will be important for achieving emission reductions to get on track with the Net Zero Scenario. 

Well-to-wheel (wake/wing) GHG intensity of motorised passenger transport modes

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Energy

The overall final energy mix of rail is currently split roughly equally between diesel and electricity, with diesel consumption slightly higher overall in 2021 than electricity. By 2030 in the Net Zero Scenario, electricity makes up around two-thirds of total final energy demand, with diesel still accounting for around a quarter, and biodiesel for the remaining share, with minimal penetration of hydrogen.

Diesel specifically plays a much more prominent role in freight rail, accounting for around two-thirds of its total energy consumption worldwide in 2021. Continuous progress on freight electrification sees this share dropping to around 40% by 2030 in the Net Zero Scenario.

Energy consumption for rail by fuel in the Net Zero Scenario, 2021-2030

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The overall final energy mix of rail is currently split roughly equally between diesel and electricity, with diesel consumption slightly higher overall in 2021 than electricity. By 2030 in the Net Zero Scenario, electricity makes up around two-thirds of total final energy demand, with diesel still accounting for around a quarter, and biodiesel for the remaining share, with minimal penetration of hydrogen.

Diesel specifically plays a much more prominent role in freight rail, accounting for around two-thirds of its total energy consumption worldwide in 2021. Continuous progress on freight electrification sees this share dropping to around 40% by 2030 in the Net Zero Scenario.

Activity

The world’s operating metro systems cover over 20 000 km. Over one-quarter of these were put into operation in 2017-2021, and 80% of these new metro lines were built in Chinese cities. The picture for light rail, which has lower capacities and speeds, is similar, if less stark: 10% of operating lines were put in place in the same five years, with just under half of them in China. The resulting efficiency of urban mobility in China results in far lower per-capita transport emissions than in cities of the rich world that are not served by metro, and can help China realise its net zero CO2 emission commitments

Over 25 countries have developed high-speed rail networks, totalling more than 45 000 km of track. China already has about 60% of the world’s track length, and aims to have 38 000 km operating by 2025. Under the Net Zero Scenario, activity levels in high-speed rail need to increase by 60% by 2030.

Night rail services can also raise throughput on networks, thus reducing the per-passenger cost of railway operations. Renewed interest has led to an expansion of night rail connections, demonstrating that this form of travel is gaining appeal and becoming a valid competitor with aviation for short- and medium-distance trips. Europe has seen the opening of several new night lines, including:

  • OBB's Nightjet train from Paris to Vienna, launched in December 2021, running three times a week in both directions.
  • Nightjet’s Amsterdam to Zurich train, passing through the German cities of Cologne, Bonn and Frankfurt, before crossing into Switzerland at Basel.
  • European Sleeper’s night train from mid-2022, leaving Brussels at dinner time and passing through major cities including Amsterdam, Hanover and Berlin, before arriving at Prague at 10:30 a.m.
Innovation

Demonstration projects in the Netherlands and Japan aim to test the viability of hydrogen as an alternative to diesel rail lines with low utilisation and as a low-carbon fuel for rail in certain operations, including for conventional (intercity) passenger rail and for freight rail.

Proponents of fuel cell trains point to their potential to run over long ranges (up to 1 000 km at a maximum speed of 140 km/h) without refuelling. They also point to the potential for quick refuelling times.

Germany recently started operating 14 hydrogen trains to serve passenger transit over a 100 km track in the state of lower Saxony. This has been the first delivery by the train manufacturer Alstom of a larger order totalling 41 trains.

Hydrogen projects have often been clustered among advanced economies, which have more financial resources at their disposal to invest in innovative technologies. This past year has seen some emerging and developing economies also investing in hydrogen rail projects, notably India’s 89 km long Sonipat-Jind route

Policy

A range of recent policies allocate public funding to extend railway infrastructure, modernise fleets and upgrade digital operations (including software and equipment).

Recommendations for policy makers

Making rail more viable is not only a matter of focusing on trains and tracks, but also requires measures to tame traffic. Fiscal measures such as congestion charges and emission taxes, applied primarily to roadways and aviation, and based on the use of the transport network and externalities, can directly increase the competitiveness of rail. For instance, internalising the environmental and social externalities of aviation through a tax levied on aviation fuels would help level the playing field and make high-speed rail more cost-competitive for long-distance travel.  

Meanwhile, some share of the revenues generated from fuel taxes, parking fees, road pricing and tolls can be invested in rail infrastructure and can encourage modal shift by reducing the appeal of private vehicle use. Similarly, proceeds from transport taxation (e.g. vehicle purchase and registration taxes) could be allocated to rail improvements and extensions. 

Recommendations for the private sector

Conventional rail companies will need to upgrade their rolling stock and further electrify services, starting with the most heavily utilised routes. Introducing energy efficiency measures would both reduce environmental impacts and improve economic viability. 

The adoption of digital technologies could optimise rail operations and integrate rail more comprehensively with other mobility services, making rail more accessible, convenient and attractive. Digital tools are therefore important for improving operational and energy efficiency, cutting costs and increasing revenues. 

Rail development financing does not need to rely solely on taxation. Capturing land value benefits can also offset high capital investment costs. For instance, network developers can capitalise on increased land values by undertaking high-profit commercial and residential projects near railway nodes and stations. Plus, financial and regulatory systems should encourage railway companies to access sustainable financing sources such as green bonds.  

Policies that promote high-density living and incorporate transport into urban development planning can help achieve high passenger throughput on urban rail networks. Adopting an integrated approach to transport can minimise commuting times. Furthermore, land use planning should accommodate city logistics by incorporating ideally located multi-modal hubs. These should link rail to cargo, cycling infrastructure and zero-emission fleets. Transit-oriented development can connect urban rail with bus networks as well as pedestrian and cycle paths.

Investing in rail infrastructure is expensive. For a rail construction project to pay off, high passenger or freight throughput is necessary. The adoption of digital technologies could optimise rail operations and integrate rail more comprehensively with other mobility services, making rail more accessible, flexible, convenient and attractive. Digital tools are therefore important to increase throughput and improve operational and energy efficiency, helping cut costs and increase revenues. 

Acknowledgements
  • Taylor Reich, Institute for Transportation & Development Policy, Reviewer 
  • Philippe Stefanos, International union of railways (UIC), Reviewer