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About this report

Rail accounts for 8% of global passenger travel and about 9% of freight activity, but only 3% of transport energy use. Extensive expansion of urban and high-speed rail has occurred over the past decade, with China leading the way. Vast electrification of rail lines is taking place in India, which has the second-longest rail infrastructure after China, and a few other regions have recently been undertaking pre-commercial demonstrations of hydrogen trains.

Progress so far is encouraging, though alignment with the Net Zero Emissions Scenario pathway will require a faster shift from carbon-intensive modes such as private cars, trucks and airplanes to rail, and higher shares of low-carbon fuels in total rail subsector energy consumption by 2030.

Share of rail travel in total passenger transport activity globally in the Net Zero Scenario, 2010-2030

Tracking progress

On average, rail requires 12 times less energy and emits 7-11 times less GHGs per passenger-km travelled than private vehicles and airplanes, making it the most efficient mode of motorised passenger transport. Aside from shipping, freight rail is the most energy-efficient and least carbon-intensive way to transport goods.

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


Despite being one of the lowest-emitting transport modes, oil accounted for 55% of total energy consumption in rail and powered 28% of all passenger rail transport activity in 2020. Under the Net Zero Scenario, however, electricity and hydrogen sustain almost 100% of total passenger rail activity as soon as 2030.  

Although rail is already the most electrified transport subsector, now all new tracks on high-throughput corridors will have to be electric to achieve the Net Zero pathway. On rail lines where throughput is too low to make electrification economically viable, hydrogen or battery electric trains coupled with partial track electrification and well-located charging points will need to replace diesel trains.

Low- and zero-carbon fuel shares in passenger rail activity, 2020 and 2030 in the Net Zero Scenario


Considering the low energy and CO2 intensities of rail transport, shifting passenger activity from more intensive modes such as private cars and airplanes to rail is a key strategy for Net Zero alignment.  

Passenger rail networks are concentrated in a handful of regions – China, the European Union, India, Japan and Russia – that together register 90% of global passenger rail activity. 

Despite rapid global metro and high-speed rail system expansions in the past ten years, the share of rail in passenger transport remained roughly constant at just below 10% over the past two decades. 

Given that the passenger rail share in total transport activity must reach at least 13% by 2030 to achieve Net Zero aims, targeted and more ambitious government policies, along with advances in rail modernisation and digitalisation, are needed to support rapid and widespread shifts to rail.

The Covid-19 pandemic severely impacted rail activity. Despite drops in energy consumption and CO2 emissions, the carbon intensity of passenger and freight rail transport rose by more than two-thirds on average. This increase can be attributed to the fact that many railway companies had to continue offering services as a mobility option for society while addressing the need for social distancing. 

The strategy entailed considerable costs for railway companies, in response to which several countries announced recovery measures to support and restore rail activity. EU member states collectively allocated nearly USD 100 billion to sustainable transport as part of National Recovery and Resilience plans for post-pandemic support. Meanwhile, Germany announced investments of USD 610 million to upgrade passenger and freight rail networks, and the United States provided USD 80 million for this purpose.  

Nevertheless, financial support for railway companies should be extended (both in duration and amount), not only for pandemic-related response and recovery, but to secure the capacity required to accommodate a modal shift to rail. 

In France and Austria, airline bailouts were applied in conjunction with restrictions banning short-haul domestic air travel on routes for which rail provides a journey time of 2.5-3 hours or less.  

Such measures take advantage of policy opportunities to couple strategies facilitating modal shifts with financial relief packages and  creating jobs by upgrading rail systems. It should be noted, however, that while bans on short-haul flights can eliminate unnecessary air travel in favour of rail for short distances, this measure should also be a permanent component of a larger policy package to address aviation emissions.  

Freight rail has the potential to provide the least energy- and CO2-intensive way to move freight of any land-based transport mode. On average, trains are almost eight times more energy-efficient and emit four times less GHGs than trucks per tonne of freight carried. Although growth in freight rail transport activity was very rapid in the early 2000s, it has since slackened and levelled off. 

China and the United States remain the largest markets for movement of freight by rail, with each accounting for one-quarter of rail freight activity. However, recent initiatives in other countries signal a push towards greater rail freight transport.  

EU measures to stimulate rail freight were announced in 2020, including temporary toll-free tracks for freight trains, toll reductions of up to 50% by 2021, and priority development of major rail systems. Ambitious national rail freight strategies in France and Belgium followed in 2021. Meanwhile, with the release of the EU Sustainable and Smart Mobility Strategy in 2020 came a target to double rail freight by 2050. Additionally, Chile has announced plans to double its freight rail volumes by 2027.  

Sustained policy action will be key to scale up freight transport by rail and overcome the rising demand for rapid delivery of high-value and lighter goods that has led to the ongoing shift from rail to road. Investments in intermodal hubs and freight corridors, when warranted by long-term certainty, can help supply chains integrate rail use.

Just a decade ago, China had virtually no high-speed rails. Now two out of three high-speed lines are in China and more than 600 billion passenger-km are travelled by high-speed rail every year.  

In 2020, China revealed plans to double its high-speed rail network from 36 000 km to 70 000 km over the next 15 years. Once built, all cities with populations greater than 200 000 will have rail line connections. Recently, China launched its first fully electrified bullet train in Tibet and announced the completion of a hydrogen-fuel cell hybrid train.  

Continued rail expansion in China will be important to facilitate a shift away from road and air travel, stem rising CO2 emissions and improve air quality.

India’s Ministry of Railways announced plans to electrify broad-gauge routes to achieve 100% electrification by 2023 and net zero emissions by 2030. So far, 45 881 route km have been electrified and, despite the Covid-19 pandemic, Indian Railways recorded the highest-ever electrification of sections across its network during 2020 and 2021. Additionally, Indian Railways is one of the 35 members of the International Union of Railways that have formally committed to net zero emissions before 2050.  

To kick off the concept of hydrogen mobility in India, Indian Railways has launched bids for the development of a hydrogen fuel cell train. The project will require establishment of a hydrogen storage facility and supply chain. 

In Germany, two hydrogen fuel cell passenger trains have been operational since 2018. Since then, several other countries have also begun to deploy hydrogen trains or have announced plans to do so in the near future.  

Country Entry into operation
(or expected deployment)
Number of trains
Netherlands2020 (2024)1 (4)
Japan2022 (testing phase)1
France2023 (testing phase)12

Notes: TBA = to be announced. Dates/train numbers in brackets represent additional project announcements.

In addition to these projects, Germany, Spain, Belgium and Portugal are partnered in the European Union’s FCH2RAIL venture to develop a train that runs on a combination of electricity and hydrogen. 

Fiscal measures such as congestion charges and emissions taxes based on use of the transport network and externalities are the most direct policies to increase the competitiveness of rail. 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, revenues from parking fees, road pricing and tolls can be invested in rail infrastructure and can encourage a modal shift by reducing the appeal of private vehicle use. Similarly, proceeds from transport taxation (i.e. vehicle purchase and registration taxes) could be allocated to rail improvements and extensions. 

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, linking rail to cargo, bicycle and other zero-emission fleets, and transit-oriented development can connect urban rail with bus networks as well as walking and cycling paths.

Conventional rail companies need to upgrade their rolling stock, further electrify their services and adopt more efficient technologies, starting with the most heavily utilised routes. This is crucial to improve the economic viability of rail systems and stem rising CO2 emissions from transport.  

However, 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, which would help cut costs and increase revenues.

Night rail services can also raise throughput on networks, thus reducing the costs of railway operations. Renewed interest in night trains 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 medium-distance trips. 


The authors would like to extend their gratitude to Benjamin Welle (World Resource Institute), Taylor Rich (ITDP), Lucie Anderton (UIC), Alice Favre (UIC), Pinar Yilmazer (UIC), Isabelle De Keyzer (UIC), Philippe Stefanos (UIC) and Martin Polák (UIC).