Train: DEFRA 🇬🇧

Calculate passenger rail emissions with the UK government's DEFRA conversion factors, by train type and energy scope, pinned to a Conversion Factors year if you need to.

type trainmethodology DEFRASupports audit mode

About the methodology

DEFRA (Department for Environment, Food & Rural Affairs) provides conversion factors and guidelines for calculating greenhouse gas (GHG) emissions across sectors, including passenger rail. As one of the main references for emissions reporting in the UK, DEFRA's methodology keeps assessments of train travel consistent, transparent and accurate.

The methodology covers direct emissions from train fuel combustion and indirect emissions from electricity consumption. DEFRA distinguishes between electric and diesel trains, and emissions vary with fuel type, train type (for example national, international, light rail) and distance travelled. The framework is widely used in corporate GHG reporting.

Versions

Add methodology_version to pin a DEFRA Conversion Factors year (for example "2024"). If you omit it, SQUAKE automatically applies the latest supported year. Pin a year for reproducibility and audit readiness.

Sample requests

Send a quote before booking, then repeat the call with audit set to true once the booking is final. The body is otherwise identical.

{
  "expand": ["items"],
  "items": [{
    "audit": false,
    "type": "train",
    "external_reference": "test_1",
    "origin": "BER",
    "destination": "FRA",
    "number_of_travelers": 3,
    "train_type": "national",
    "methodology": "DEFRA",
    "energy_scope": "ttw",
    "methodology_version": "2024"
  }]
}

audit_for is optional

Pass the ID of an auditable entity when you calculate on behalf of that entity. Otherwise, leave it out.

Defaults

Field	Default	Applies when
`train_type`	`national`	No `train_type` is sent
`energy_scope`	`wtw`	No `energy_scope` is sent
`methodology_version`	Latest supported DEFRA year	No `methodology_version` is sent

Request fields

typestringrequired

train

methodologystringrequired

DEFRA

methodology_versionstring

DEFRA Conversion Factors year, for example "2024". If omitted, SQUAKE uses the latest supported year.

external_referencestring

A unique identifier to link the result, up to 128 characters.

number_of_travelersinteger

Minimum 1. Defaults to 1.

originstring

Flexible formats: postal, IATA/ICAO (^[A-Z]{3,4}$), UN/LOCODE (^[A-Z]{2}\W?[A-Z2-9]{3}$) or "lat,lon". SQUAKE resolves the distance automatically. See Origin and destination formats.

destinationstring

Same formats as origin.

distance_in_kmnumber

If provided, overrides origin and destination.

train_typeenum

Supported categories (per DEFRA): "national", "international", "light", "tram", "underground".

energy_scopeenum

"wtw" (default) or "ttw".

auditboolean

Set to true to create immutable audit records for finalised calculations. Must be enabled for your account.

See every field of POST /v2/calculations in the API reference

Origin and destination formats

SQUAKE tries to resolve origin and destination whatever their format. Ideally, use:

Addresses: the Post standard.
Airports: an IATA/ICAO code (regex ^[A-Z]{3,4}$, for example "MUC").
Ports and trade locations: a UN/LOCODE (regex ^[A-Z]{2}\W?[A-Z2-9]{3}$, for example "DEHAM").
Coordinates: latitude and longitude (regex ^[-+]?\d{1,3}\.\d{1,10}\s?,\s?[-+]?\d{1,3}\.\d{1,10}$, for example "+40.712,-74.006").

UIC and provider codes

A UIC code is also a valid format for trains. If the value isn't valid, the system falls back to general, non-journey-specific emission data.

To use a UIC or provider code, send <provider>:<uic_code>, for example sncf:FRAAA. Possible provider prefixes: uic, uic8_sncf, sncf, sncf_tvs, entur, db, busbud, distribusion, flixbus, cff, leoexpress, obb, trenitalia, trenitalia_rtvt, trenord, ntv_rtiv, ntv, hkx, renfe, atoc, benerail, westbahn.

{
  "type": "train",
  "methodology": "DEFRA",
  "origin": "atoc:1072",         // Example UK station code structure
  "destination": "atoc:5935",
  "number_of_travelers": 1,
  "energy_scope": "wtw",
  "methodology_version": "2024"
}

Distance and fallback

If you send both origin/destination and distance_in_km, SQUAKE uses distance_in_km for emissions.
Invalid, unsupported or unresolvable location codes trigger a fallback to generic (non-journey-specific) factors consistent with the DEFRA methodology.

Sample response

200 OKapplication/json

{
  "carbon_quantity": 6669,
  "carbon_unit": "gram",
  "items": [{
    "carbon_quantity": 6669,
    "carbon_unit": "gram",
    "external_reference": "test_2",
    "type": "train",
    "methodology": "DEFRA",
    "methodology_version": "2024",
    "distance": 435.0,
    "distance_unit": "kilometer"
  }]
}

Bibliography

UK Government: Greenhouse gas emissions: Research & statistics.
DEFRA (2024). Government Greenhouse Gas Conversion Factors for Company Reporting (Rail factors).
UK Office of Rail and Road. National Rail Trends.
Eurostar. GHG Methodology Report.

Train: DEFRA 🇬🇧

About the methodologyCopy Anchor Link

VersionsCopy Anchor Link

Sample requestsCopy Anchor Link

DefaultsCopy Anchor Link

Request fieldsCopy Anchor Link

Origin and destination formatsCopy Anchor Link

UIC and provider codesCopy Anchor Link

Sample responseCopy Anchor Link

BibliographyCopy Anchor Link

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