Battery passport for trams and rail rolling stock
Counter-intuitive, and decisive for scoping the project: a tram traction battery is not an electric vehicle battery under the Regulation. It is an industrial battery — 36 mandatory data points, and a 2 kWh threshold for the passport obligation.
Industrial battery above 2 kWh — 36 of 71 data points mandatory
on 18 February 2027
The definition of an electric vehicle battery covers vehicles of categories L, M, N and O — that is, road vehicles. A tram, a train or a tram-train belongs to none of them. Recital 15 of Regulation (EU) 2023/1542 settles the point explicitly: batteries intended for traction in rail, waterborne and air transport are industrial batteries. In practice this means the industrial battery regime applies — 36 mandatory data points on 18 February 2027, and a passport obligation above 2 kWh.
Applicable threshold. The passport is required for industrial batteries above 2 kWh. Rolling stock traction packs exceed that threshold by orders of magnitude, so the criterion excludes no traction pack in practice — but it can exclude low-capacity auxiliary batteries.
Source: Regulation (EU) 2023/1542 and the European Commission guidance document "Digital Batteries Passport – data points by category", version 2.0 of 15 August 2026, which lists 71 data points and their applicability by battery category.
What is in scope, and what is not
Subject to the passport
- Traction packs on battery-powered trams and tram-trains
- Batteries on bi-mode trainsets and battery trains running on non-electrified lines
- Shunting and back-up batteries above 2 kWh
- Replacement batteries fitted during retrofit and placed on the market after 18 February 2027
Out of scope
- Purely catenary-powered rolling stock, with no traction battery and no on-board battery above 2 kWh
- Auxiliary batteries of 2 kWh or less, outside the passport obligation
What you actually have to produce on 18 February 2027
Not every data point in the passport is due when it opens. The Commission guidance distinguishes, for each battery category, what is mandatory at the deadline from what is still waiting for its legal framework. Scoping the project against the full list means over-investing; ignoring the distinction means rebuilding in two years.
Mandatory at the deadline
- ✓Unique identifier per pack and economic operator identifier
- ✓Manufacturer, model, date and place of manufacture of the pack
- ✓Chemical composition, critical raw materials and hazardous substances
- ✓Rated capacity, power, voltage and expected service life
- ✓State of health and usage history, restricted to legitimate interested parties
- ✓Module-by-module disassembly instructions and depot safety information
Not yet due — and why
- ○Carbon footprint declaration: for industrial batteries it only becomes due twelve months after the delegated act setting the calculation methodology enters into force — an act still in draft
- ○Responsible sourcing information: the methodology is not finalised, and the Article 48 due diligence obligation is postponed to 18 August 2027
- ○Recycled content declaration: due from 18 August 2028, with minimum thresholds applying on 18 August 2031
Also worth tracking: supply chain due diligence obligations (Article 48), postponed to 18 August 2027 by Regulation (EU) 2025/1561, with an exemption for companies with a turnover below EUR 40 million.
Where the data comes from in this sector
The hard part of a Battery Pass project is almost never the passport itself: it is knowing who holds each piece of data, how often it changes, and who is entitled to read it. Article 77 and Annex XIII impose tiered access — not every mandatory data point is public.
| Data | Who holds it | Frequency | Access |
|---|---|---|---|
| Pack identifier and module-level bill of materials | Rolling stock integrator and traction system supplier | At creation | Public |
| Chemical composition and critical raw materials | Cell maker, passed up by the integrator | At creation | Interested parties |
| Safety certificates and test reports | Laboratories and notified bodies | At creation | Authorities |
| State of health per module | On-board BMS, relayed by the fleet supervision system | Continuous | Interested parties |
| Maintenance work and module replacements | Operator or maintainer depot | Per intervention | Interested parties |
| Disassembly and treatment route | Manufacturer, with the approved recycler | At creation | Public |
How state of health gets in when the battery is not connected
State of health is the only passport data that has to stay alive after the battery is placed on the market. The market talks about connecting to the BMS as if it were a given — it is not: most batteries in service report nothing continuously. Three routes coexist, and on this segment it is batch import that is the realistic default.
The BMS reports state of health continuously, through vehicle telematics or site supervision. The finest-grained option, but it assumes connected equipment and a data flow that already exists.
Possible where on-board supervision already exposes traction data trackside, module by module.
With Arianee — Event-based write API: each reading updates the passport of the battery concerned, with no re-issuance, timestamped and attributed to its source.
Readings are extracted periodically from an existing system — supervision, fleet management, connected chargers, ERP — and loaded in batches. The realistic route when the data exists but is not exposed in real time.
The usual route: extraction from the fleet supervision system at each scheduled maintenance visit, covering the whole trainset in one operation.
With Arianee — Bulk import from the Management Hub or by API: one file or feed updates thousands of passports in a single operation, with a per-line error report.
The technician scans the battery's QR code and enters or confirms the reading on the spot — in the workshop, in store, in the plant room. The only route when the battery is not connected, and the most reliable evidence that an intervention took place.
In the depot, during heavy overhauls: the technician scans the removed module, records its condition and the replacement performed.
With Arianee — Passport Portal: the scan opens the battery's passport with the technician's rights, and they write their reading and their intervention. Works for a network of third-party workshops without opening the rest of the fleet to them.
The three routes feed the same passport and are not mutually exclusive: a mixed estate usually combines a BMS feed on recent equipment, a batch import for the installed base, and a field reading for anything that comes through the workshop. Every write is timestamped and attributed to its source, which is what makes the history hold up under inspection.
The three hard parts specific to this sector
Rolling stock lives thirty years, and so must the passport
A trainset stays in service for three or four decades. The passport has to survive changes of supplier, of information system and of maintainer, remain readable and writable throughout, and not depend on any single provider staying in business.
Short runs, bespoke packs
Rail does not build long production runs: each contract produces its own configuration, sometimes a few dozen trainsets. The data model has to accept variants without multiplying development, and passport creation has to stay economic at low volumes.
Retrofit and spare parts
The obligation attaches to placing the battery on the market, not to the age of the rolling stock. A replacement battery, or a pack fitted during retrofit on an older trainset, placed on the market after 18 February 2027, needs its passport. Older fleets are therefore not out of scope.
What the passport gives you beyond compliance
A battery passport reduced to an obligation stays a cost. The same data, properly structured, serves operations and the residual value of the fleet.
Answering public tenders
Transport authorities are progressively writing traceability and environmental footprint requirements into their specifications. A passport that already works becomes part of the answer rather than a future constraint.
Condition-based maintenance per module
Tracking state of health at module rather than pack level allows you to replace what has degraded instead of the whole assembly, and to document each intervention in the passport for operator and maintainer alike.
Residual value and second life
A removed traction pack retains useful capacity for stationary storage. A documented usage history determines whether it can be resold rather than recycled.
François Pujo
Industrial & Battery Project Manager
François is our Battery Pass expert, working alongside industrial players worldwide to integrate DPP into their production lines and across the entire life of the product.
Frequently asked questions — Trams & rail
Is a tram battery an electric vehicle battery under the Regulation?+
No. The definition of an electric vehicle battery in Article 3 of Regulation (EU) 2023/1542 covers vehicles of categories L, M, N and O, which are road vehicle categories. A tram is not among them. Recital 15 of the Regulation states that batteries intended for traction in rail, waterborne and air transport are classified as industrial batteries. A tram traction battery is therefore an industrial battery.
What does that classification change in practice?+
Three things. First the number of data points: 36 of the 71 listed in the Commission guidance are mandatory on 18 February 2027 for industrial batteries, against 51 for electric vehicle batteries. Second the threshold: the passport is only required above 2 kWh. Third the timetable for the related obligations — carbon footprint and recycled content — which follows the industrial battery schedule, not the electric vehicle one.
Does rolling stock already in service need a passport?+
The passport attaches to the battery placed on the market, not to the vehicle. A trainset delivered before 18 February 2027 does not need a retrospective passport. Any replacement battery or retrofit pack placed on the market after that date does. Operators of older fleets are therefore affected through their future purchasing.
Who is responsible for the passport: the manufacturer or the operator?+
The obligation falls on the economic operator placing the battery on the Union market — in practice the rolling stock manufacturer or the traction system supplier, depending on the contractual structure. The operator is not responsible for creating the passport, but it holds part of the data that has to be kept current during service, in particular state of health and maintenance history.
Must the passport stay accessible for the whole life of the trainset?+
Yes. Article 77 provides that the passport remains accessible until the battery is recycled, which for rolling stock means several decades. That is an infrastructure selection criterion in its own right: the data must remain readable and writable regardless of whether any given supplier is still trading.