Train
Calculate train travel emissions on the Calculation API with one of the train methodologies below. The REM page recommends "methodology": "REM", the operator- and country-aware rail methodology, for all new integrations.
Choose a methodology
| Methodology | Coverage | Basis | Inputs you need | Notes |
|---|---|---|---|---|
| REM | Operator and country factors, with global averages as the last tier | Rail Emissions Model, five-tier factor resolver | origin and destination, distance_in_km or route_coords; optional operator_name, origin_country, destination_country, departure_date, train_type, fuel_type, energy_scope | algorithm_specifics reports the tier used; route_coords gives a border-aware distance |
| ADEME 🇫🇷 | Not stated | GHG information for transport services (French ministry, June 2019) | origin and destination or distance_in_km; optional train_type, fuel_type | Full lifecycle, including infrastructure; fuel_type defaults to diesel |
| Base Empreinte 🇫🇷 | France by default, with Corsica and Île-de-France options | ADEME Base Empreinte, 2025 | origin and destination or distance_in_km; optional train_type, state, country, city_type, year | Factor year defaults to the latest available |
| CO2-emissiefactoren 🇳🇱 | Not stated | CO2-emissiefactoren, yearly sets 2020, 2021, 2023, 2025 and 2026 | origin and destination or distance_in_km; optional methodology_version, train_type, fuel_type, energy_scope | train_type is only average or international; year isn't inferred on this endpoint |
| DEFRA 🇬🇧 | Not stated | UK government DEFRA Conversion Factors | origin and destination or distance_in_km; optional methodology_version, train_type, energy_scope | Train types: national, international, light rail, tram, underground |
| Green Travel Data 🇬🇧 | GB National Rail | Rail Delivery Group Green Travel Data 2.0 and 3.1 | origin and destination as CRS station codes; optional seat_type, departure_date, distance_in_km | Station-to-station figures per timetable release; distance_in_km needed for the fallback |
| US-EPA 🇺🇸 | US passenger rail: intercity, commuter and transit | US EPA GHG Emission Factors Hub | distance_in_km (preferred) or origin and destination; optional train_type, methodology_version | Tank-to-wheel only, no upstream emissions |
Every methodology above supports audit mode. If you leave methodology out on a train item, the API uses your client's configured train default.
How to decide
- You know the operator or the countries travelled: REM uses
operator_namefor operator-reported factors and the country fields for country-level factors, and reports which tier answered. - The journey is on GB National Rail and you have CRS codes: Green Travel Data uses the Rail Delivery Group's per-journey figure for the timetable that covers
departure_date. - The journey is US passenger rail: US-EPA has factors by US service class, such as
intercity_northeast_corridorandcommuter_rail. - You need to reproduce a published factor year: DEFRA, CO2-emissiefactoren and US-EPA take a
methodology_version, and Base Empreinte takes ayear. - You need tank-to-wheel or well-to-wheel figures: REM, DEFRA and CO2-emissiefactoren accept
energy_scope. US-EPA is tank-to-wheel only.