A small number of direct journeys (approx. 1% of the total) are not covered in the results.

These journeys are missing because passenger loading information isn’t available for the current timetable, typically because the timetable has changed recently, or there is long term engineering work affecting services.

In these cases, we will work to add information at the next six-monthly data review.

As part of our ongoing analysis, we continually improve our algorithms and implement enhancements from time-to-time to achieve higher accuracy in our calculations. The figures released for both Phase 1 and Phase 2 are based on the most recent available data sets at the time of release.

This can result in slight variations in emission values between the two phases due to factors including:

• A larger sample size of data becoming available, providing more data points for analysis
• New rolling stock entering service and changing the balance of energy usage
• New routes and services being introduced
• Routes and timetables changing; and
• Industrial action affecting passenger numbers, train stops and service frequency.

For a small number (under 1%) of journeys, there is a minor variation (under 2%) in the base data between Phase 1 and Phase 2 measurements. This variation is due to improvements and corrections made in the calculation process for Phase 2.

During this process, an anomaly was discovered in some Phase 1 calculations where the whole train journey was included rather than the journey leg. This issue has been corrected in the Phase 2 data set, resulting in the observed minor variations.

No, our rail data does not take into account strikes or unexpected service disruptions. The dataset incorporates forecasted passenger data for regular, scheduled rail travel on weekdays and does not include data on strikes, delays, cancellations, or other unplanned interruptions to service.

Green Travel Pledge has used the Government’s most recently released set of emission conversion factors (‘Conversion factors 2024’) which were published by the Department for Energy Security and Net Zero (DESNZ) on 8 July 2024.

Car emissions were sourced from the Government's Department for Energy Security and Net Zero, Greenhouse gas reporting: conversion factors 2024, using the "Business Travel - land" data set, specifically the ‘Executive car’ kgCO2e per km figure - which is business travel in other vehicles (e.g. employee own car for business use, hire car, public transport (Scope 3)).

The route distances were calculated using the OSRM (Open Source Routing Machine) project. Coordinates for each station pair were processed to determine the shortest road route. If a station wasn’t directly accessible by public roads, the nearest accessible road was used.

By multiplying the 'kgCO2e per km' figures with the route distances, we obtained emissions data for single-occupancy petrol/diesel, hybrid plug-in electric, and battery electric cars used for business travel.

While train travel is usually greener than other modes of transport, emissions can be relatively high on a small number of routes. This variation can be due to a number of factors, including low passenger numbers and the use of less environmentally friendly fuel types on some routes.

This isn’t currently available as part of Green Travel Pledge data.

Green Travel Pledge identifies the direct services between the two station and works out the emission value for each service (per km emission value for the booked train type x the distance).

From this, we calculate average emissions of trains on the route, which is divided by the average passenger load.

Green Travel Pledge has used the UK Government’s Greenhouse Gas Conversion factors and the Business Travel by land - Unknown category for car emissions, which covers diesel and petrol cars.

Green Travel Pledge has used the UK Government’s Greenhouse Gas Conversion factors for car emissions which covers battery electric cars.

This energy value is then turned into an emission figure by mapping to the UK Government’s Greenhouse Gas Conversion factors.

This energy value is turned into an emission figure by mapping to the UK Government’s Greenhouse Gas Conversion factors.

These routes were chosen to align with our ‘Clearing the Air: Train vs Plane’ report comparing train and airline travel on a number of different factors.

To provide the fairest comparison with domestic airline travel, we have used Thrust Carbon’s ‘Thrust Shop’ carbon calculator for emissions, which is based off the UK Government’s Greenhouse Gas Conversion factors (GGH).

The reason for the difference between June 2023 and April 2024 airline data for a trip between London and Edinburgh is because we previously used just the GGH data. This time we have used Thrust Carbon’s ‘Thrust Shop’ calculations, which are slightly lower as they have been amended to take into account other factors, such as removing prop planes which would not be used for business travel on this route.

Standard as Business Class and First Class are not often available on domestic flights in the UK.

Green Travel Pledge per passenger emission figures take into account a lot more than just the distance of the journey.

The type of train (and fuel it uses), the number of carriages that make up the train and the amount of customers on the train (especially off-peak services that may be quieter at certain times of the day) can heavily impact the overall per passenger emission figure on each route.

Green Travel Pledge data currently covers Monday to Friday business travel, not all rail travel. We are looking at expanding this to take into account seven days a week travel in future phases.

This would ensure Green Travel Pledge would be more relevant for public-facing campaigns, which include leisure travel, such as those mentioned above.

Not at this stage as we have focused purely on the rail journey emissions.

We use rail industry demand modelling software to predict which train each passenger is likely to travel on. This model is built up from trends dating back over a decade applied to current passenger levels. From this model we are able to build up a comprehensive view of how many people travel on each train and therefore each route on a typical day.

Energy values per kilometre are derived for electric trains from Network Rail EC4T data.

Green Travel Pledge uses MOIRA modelled data to derive the loading for each direct service between any two station pairs. From this we can work out the passenger mileage between those two points and from that the average loading value for all services. This data is currently derived from the May 2023 timetable. Future data publications will be updated to reflect the forecast for the latest timetable. Please refer back to the Green Travel Pledge website for any updates.

No, Phase 1 data for the top rail business routes in Britain is still preliminary data and will continue to be improved upon as we seek richer and more granular travel data from within the industry.  

In summer 2024, we plan to release Phase 2 which will use updated timetable information to create a newer and even more accurate data set.

Yes the figures take into account travel in either direction.

Passenger forecasted data is used for the Green Travel Pledge, which includes first class data captured at the point of sale.

First class ticket upgrades, whether through an external auction site, operators own upgrade pre departure site, walk up upgrades, on board upgrades are not included.

Permanent declassification - where a number of train operators under instruction from the Department for Transport have withdrawn First Class from their services, will be included if it is a moment of time that the data covers.

Due to high passenger loads on certain routes and certain journeys, operators will make the decision to declassify to make seat space for passengers and therefore this data is not captured within Green Travel Pledge.

Yes, as the data used includes passenger load, this will include any passengers on the train.

We currently only use data for Monday to Friday travel, as this is typically when business travel on British trains takes place. We are considering expanding our data sources to include weekend travel in future.

At this stage of the Phase 1 launch (February 2024), the project is publishing average forecasted data only. This approach is continuously under review, as we look to improve the granularity of available data.

At this stage, we are providing an average figure to allow for a comparison with the average rail / car emission figure currently used by Government. In future, we aim to release distinct emission totals for First Class and Standard Class journeys for all direct business routes in Britain, but this requires some additional information to ensure it takes into account First Class travel via third party upgrades, on the train upgrades and other routes.

At this stage Rail Replacement Buses are not included within the Green Travel Pledge data. As the data is forecasted rail. This will be reviewed for future phases.

If a ticket is purchased for travel or a seat booking is made, then this would count towards the occupancy figures we use to calculate the per passenger emissions. There are some cases in which a line pass or on the day upgrade is purchased, which may mean that we do not take into account certain journeys.

Catering on the train is not included in this phase of the initiative but will be considered in planning future phases.

How staff get to the station to support the running of the train is not included in this phase of the initiative but will be considered in planning future phases.

We consider Standard Premium as Standard travel for the purposes of calculating rail emissions.

At Phase 1, we have received data from the vast majority of train operators, including train operators running services on all of the top 100 business routes.

Green Travel Pledge is the rail industry’s commitment to provide detailed, accurate and reliable data on the carbon emissions of rail journeys so that:​

• The sustainability benefits of travelling by train become clearer and even more compelling;​
• Businesses and their travellers are empowered to make more informed choices;​
• The business travel sector can make data on rail journey emissions easier to access and use at the point of sale;​
• Businesses can accurately measure the emissions of their rail travel to track their progress against sustainability goals.

The pledge will help encourage businesses to modal shift away from car and plane travel to stimulate additional business journeys by train.

It is a rail industry initiative being led by the Rail Delivery Group, in partnership with Great British Railways Transition Team, creating a recognised industry benchmark for carbon emissions.

We have developed a new rail carbon calculator which provides detailed, accurate and reliable data on the carbon emissions of rail journeys to businesses at the point of sale.

This new tool allows businesses and business travellers to easily demonstrate the green credentials of switching to rail travel from less environmentally-friendly alternatives such as car and plane travel.

If you're a business, travel management company or online booking tool provider who would like access to this data, please contact This email address is being protected from spambots. You need JavaScript enabled to view it..

Currently, we are developing this as a product for businesses, travel management companies and online booking tools.

Therefore, the results will be available via an open API which will then be displayed to business travel customers at the point of sale.

We hope that by showing a reliable and accurate carbon footprint for rail, we can encourage business travellers to switch from less environmentally-friendly alternatives such as car and plane travel.

We are gradually rolling out carbon calculations for rail routes across Britain. We started with provisional figures from London King’s Cross to Edinburgh Waverley as this is a popular route with business travellers and gave an opportunity to compare long distance train, plane and car travel.

We are now focusing on calculating carbon emissions for the top long-distance rail business travel routes. In 2024 we plan to finalise data for all point-to-point rail business routes across Britain.

We want to help encourage businesses to modal shift away from car and plane travel to stimulate additional business journeys by train.

Please contact us at This email address is being protected from spambots. You need JavaScript enabled to view it. to discuss your involvement with the Green Travel Pledge project.

If you're a business, travel management company or online booking tool provider who would like access to this data, please contact This email address is being protected from spambots. You need JavaScript enabled to view it..

The calculation is per passenger. This takes into account occupancy data to provide a reliable figure for how many people will be using each route.

We have been working with carbon emission experts at Thrust Carbon and rail data specialists at Fabrik to compile rail data and use it to accurately calculate rail emissions for all point-to-point rail journeys in Britain.

Data used includes: engine type, fuel type, journey distance, number of carriages, travel class, occupancy and timetable.

To find out more technical detail on how we calculated our preliminary carbon calculations for a journey from London King’s Cross to Edinburgh Waverley, please read Thrust Carbon's blog.

Current emission measures, such as the one maintained by the Department for Energy Security and Net Zero (still colloquially known as the ‘Defra methodology’), offer a general average emission figure for all customers on rail services in Britain. However, they do not differentiate between various factors including: different classes of travel, load factor, or electric vs diesel power units.

The ’Defra methodology’ calculates a single emission factor for the average passenger per kilometre, which, while useful for high-level comparisons, does not accurately reflect the emissions associated with individual passengers on specific journeys.

Our Green Travel Pledge methodology fills this gap, offering a more granular and nuanced understanding of rail emissions. It considers the specific characteristics of different rail routes, and allocates emissions to individual passengers based on the following (not exhaustive): number of carriages dedicated to each class, the average load factor for each class, and the volume of trains run on each route.

This approach can provide a more accurate measure of the emissions associated with individual passengers, and can serve as a powerful tool in enabling more accurate reporting on rail emissions for businesses, whilst also shaping strategies for emission reduction in the rail sector.

Our carbon calculations for rail take into account: engine type, fuel type, journey distance, number of carriages, travel class, occupancy and timetable.

No, there are many different methods for calculating carbon emissions for train journeys.

We believe it’s important that the rail industry works from one reliable, accurate and consistent measurement of carbon emissions. That is why we are using granular data to make Green Travel Pledge carbon emission data as reliable as possible.

We plan to roll it out to businesses, online booking tools and travel management companies throughout 2024.

Currently we are only looking at direct journeys i.e. those with no changes. Where more than one train operator runs trains on that route, the data for each will be used to calculate the final figure.

However, in future we plan to include indirect journeys (those with changes), allowing rail users to ‘add up’ their emissions for multiple legs of a journey.

Our methodology uses the number of carriages and number of passengers between any two station stops on a journey and aggregates these. As such, any joining or splitting of trains would be factored into the overall emission calculations for the route as this would alter the number of carriages and passenger load.

Our methodology takes into account the type of train – electric or diesel – operating on specific routes. This allows us to estimate emissions accordingly. Where trains change from electric to diesel (and vice versa) en route, we will take this into account. 

At this stage, we will not be factoring in ‘one-off’ train cancellations. We will only factor in changes if they substantially impact the rail timetable.

For these journeys, we are able to identify the emissions for each part of the journey, and as such can calculate the emissions for the entire route, even if the route is partially electric and partially diesel.

Timetables typically change every six months in the rail industry. Our figures and methodology will be updated to reflect any changes made in the timetable to train routes or volumes.

Green Travel Pledge carbon emission data is available via the Rail Data Marketplace (RDM). RDM is a central platform for finding and sharing rail data, allowing us to share data with multiple parties quickly and easily via a number of formats.