The methodology establishes a global standard for how passenger-rail greenhouse gas emissions are quantified across operators, countries, and service types, and is now available for public review.
SQUAKE today published the whitepaper for its Rail Emission Model (REM), a methodology for consistent, transparent, and audit-ready quantification of passenger-rail greenhouse gas emissions. The whitepaper sets out how REM selects emission factors, defines its system boundary, and exposes the audit metadata behind every result. It is available now through SQUAKE, and industry stakeholders are invited to review and stress-test the methodology.
Rail emission factors are fragmented across operators, countries, and methodologies. Published factors differ because of boundary choices, electricity-accounting conventions, service-category definitions, and the vintage of the underlying data, and no single source applies consistently across regions and service types. For travel managers, TMCs, online booking tools, and corporate reporting teams, this inconsistency makes like-for-like comparison and assurance-ready reporting difficult.
REM applies a tiered fallback hierarchy that prioritizes the most specific data available, beginning with operator-level emission factors and cascading in a controlled, disclosed sequence to country-level proxies, activity-based estimates, and global defaults. It reports emissions under a Well-to-Wheel boundary on a location-based electricity basis, so results stay physically grounded and comparable across operators. Every calculation returns audit metadata, including method tier, energy scope, factor source, factor vintage, proxy geography, and distance basis, so users can see exactly how a result was produced. REM is designed to align with the principles of ISO 14083 and to support use in booking, travel-management, and corporate reporting systems.
SQUAKE is part of the Travalyst Coalition - an independent not-for-profit entity working to change the way the world travels, for good. By integrating the REM into Travalyst's Data Hub, comparable, credible data will soon be made available across the travel ecosystem at scale, helping to establish the REM as an industry standard for rail emissions.The methodology has already been shaped by rounds of expert input, including detailed feedback from the Travalyst Independent Advisory Group.
Rail is increasingly in focus of (transport) modal shift of corporate travel programs, but the data behind rail emissions is inconsistent and hard to compare. REM gives the industry a transparent, standards-aligned way to quantify those emissions and to show the assumptions behind every number. We are publishing the full methodology because we want operators, reporting teams, and our peers to challenge it to make it even more robust for the future.
The full Rail Emission Model whitepaper is available here.
SQUAKE is publishing REM openly because passenger-rail emissions data needs more consistency, scrutiny, and industry alignment. Travel managers, sustainability leads, TMCs, OBTs, rail operators, industry bodies, and corporate reporting stakeholders are invited to review, challenge, and stress-test the methodology through the feedback form here.
SQUAKE provides an end-to-end solution for business travel-related emissions calculation and climate contribution, helping organizations turn complex travel data into audit-ready carbon metrics and defensible reporting. Built for aviation, rail, road, and lodging, SQUAKE applies standards-aligned methodologies including the GHG Protocol and ISO 14083, with configurable boundaries (TTW/WTW), class-based allocations, and transparent, versioned emission factors. Rail is a core focus area, supported by an immutable Audit Mode and full methodological traceability for assurance-ready reporting, including under CSRD.
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