Railway rolling stock manufacturing
Railway weld monitoring for EN 15085 rolling stock
Thermal and process records for every weld on car bodies, underframes and bogies: what they show, how a one-cell pilot runs and what goes into the EN 15085 file.
CEN standard · reference card
EN 15085-3: design requirements for rail welding
EN 15085-3 sets the design requirements for welded railway vehicles and components. Scope decision flow, how it links to manufacturer certification, and the records an EN 15085 auditor reviews.
- Designation
- EN 15085-3
- Issued by
- CEN
- Title
- Railway applications — Welding of railway vehicles and components — Part 3: Design requirements
- Edition
- Confirm the edition your certification body works to.
EN 15085-3 is the design part of a five-part series, and it is easy to confuse with EN 15085-2, the certification part everyone talks about first. Certification proves the manufacturer is organised to weld safely; EN 15085-3 decides, joint by joint, how safety-critical that weld actually is and what class of scrutiny it therefore earns.
The classification runs on consequence of failure, not on convenience or on how the shop has always done it. A joint carried over from an older, uncertified design is the most common place this breaks: the drawing looks settled, but the stress-class, safety-category and CP-class logic behind it was never re-checked against the current standard.
Because the assigned CP class drives everything downstream — the minimum certification level under EN 15085-2, inspection extent under EN 15085-5, production controls under EN 15085-4 — a per-weld record that ties the measured process back to the assigned class is what an audit actually asks for. Therness monitoring produces that record on the welding process itself, tied to the joint identifier rather than to a batch.
Scope: does it apply to your job?
Applies to
- Design of welded joints in railway vehicles and components under the EN 15085 series
- Assigning stress class and safety category to fix each joint's weld performance class (CP A, CP B, CP C1-C3, CP D)
- Weld joint detailing and design documentation for rolling stock
Does not apply to
- Manufacturer certification and CL1-CL4 levels, covered by EN 15085-2
- Workshop production requirements, covered by EN 15085-4
- Inspection, testing and documentation, covered by EN 15085-5
Applicability decision flow
| Question | If yes | If no |
|---|---|---|
| Is the component a welded railway vehicle part within the EN 15085 series scope? | EN 15085-3 governs how the joints are designed. | A different construction code applies; EN 15085 is specific to rolling stock. |
| Has the joint's stress class and safety category been combined into a weld performance class (CP A, CP B, CP C1-C3, CP D)? | That CP class sets the minimum EN 15085-2 certification level (CL) the manufacturer must hold for this weld; check the shop's CL covers it. | Assign stress class and safety category first. The design's CP class does not depend on the manufacturer's certification level — it is the other way round. |
| Could the joint's failure affect passenger or structural safety? | Assign the higher safety category and the CP class the standard reserves for safety-critical joints. | A lower safety category and CP class may apply; document the reasoning in the design file. |
| Is the weld joint design carried over from a legacy or inherited drawing? | Re-verify it against the current stress-class, safety-category and CP-class logic before reusing it on a new certified build. | Design against the standard's stress-class, safety-category and CP-class requirements from the outset. |
What proves conformity, and what only supports it
Conformity is decided by inspection and testing against the criteria the standard and the contract set. The records below are evidence that the process was held where it was qualified; they support an inspection result, they never replace one.
| Requirement | Record produced | Source |
|---|---|---|
| Evidence that safety-critical joints were welded inside their qualified parameters | Per-weld voltage, current and wire feed records tied to the joint and its CP class | WeldTrace |
| A thermal record supporting the inspection extent a higher CP class demands | Continuous per-seam thermal record with anomaly flags | HeatCam IR-C |
| A traceable record set an EN 15085 auditor can review against the design CP class | Per-weld export with identifier, operator, timestamp and CP-class reference | HeatCore AI |
Evidence the process, not just the paperwork
Therness records what the machine actually delivered on every weld — parameters, thermal signature and a per-weld trail — so a conformity argument rests on measurements instead of recollection.
