Train Axle Specification Example for Long-Haul Trucks: Folding Type
Train Axle Specification Example for Long-Haul Trucks: Folding Type
This is a worked specification for train axle in a folding type programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The folding type version exists because the duty cycle on long-haul trucks is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually a specification nobody had written down.

Example specification
| Item | Train Axle |
|---|---|
| Application | Long-Haul Trucks |
| Version | Folding Type |
| Base material | Bronze |
| Controlled dimensions | 6 key dimensions, recorded per lot |
| Tolerance band | ±0.1 mm |
| Finish | zinc plated |
| MOQ | 2,000 pieces per specification |
| Sampling | 14 working days, 3 days per revision |
| Compliance | SAE J431 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Bronze, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.

Processes involved
- gravity casting
- electroplating
- laser cutting
- injection moulding
- precision stamping
- surface grinding
Where this example applies
Programmes that run folding type most often specify this build for long-haul trucks. Related applications include city buses, municipal fleets, fleet maintenance, utility trailers, export programmes.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the SAE J431-compliant build instead of a fresh interpretation.
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
Do you handle mixed containers?
Yes. Most programmes consolidate several part numbers into one container to keep freight sensible at 2000 pieces per line.
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.



