What the data for this category looks like
Data sources for the railway and highway category mainly include ledgers from operation management systems, line survey and design reports, daily operation and maintenance logs, quarterly financial settlement documents, and industry policy notices. Data update rhythms are divided into fixed cycles and emergency scenarios. Fixed cycles include monthly operation traffic statistics, quarterly equipment inspection reports, and annual infrastructure plans. Emergency scenarios include temporary line adjustments and disaster emergency response documents. Most document structures contain fields such as line number, stake number, mileage, equipment model, operation and maintenance duration, and cost amount. Units include kilometers, hours, ten thousand yuan, and degrees Celsius. Some long documents have nested multi-level chapter structures of "line overview - section details - equipment parameters".
What constraints these characteristics impose on the "document parsing and chunking" link
Multi-level nested document structures require parsing components to accurately recognize hierarchical headings, to avoid splitting sections and their corresponding parameters during chunking. Precise numerical fields with units need to retain the binding between fields and units, to prevent separation of values and units after chunking. Long documents (such as annual infrastructure plans that can reach hundreds of thousands of characters) require controlling chunk granularity, to avoid overloading individual chunks and affecting retrieval accuracy. Temporarily generated non-standard documents need to be compatible with parsing logic, while retaining metadata such as file timestamps and line numbers for subsequent traceability.
How to set the configurations
| Configuration Item | Recommended Value | Rationale |
|---|---|---|
chunk_size | 800–1200 characters | Railway and highway documents mostly contain long paragraphs of equipment parameters and line data. This length can retain complete information for a single section or single equipment, avoiding content splitting |
chunk_overlap | 100–150 characters | Retain hierarchical headings and field associations between adjacent chunks, preventing loss of context links between sections and parameters during retrieval |
PARSE_DOCX_STYLE_PRIORITY | heading > table > paragraph | Hierarchical headings in railway and highway documents are mostly defined via styles. Prioritizing heading recognition can accurately split chapters, and equipment parameters in tables need to be fully retained |
UPLOAD_FILE_MAX_SIZE | 2000 MB | Adapt to the upload requirements of large documents such as annual infrastructure plans, avoiding parsing failures caused by exceeding file size limits |
PARSE_FILE_TIMEOUT_SECONDS | 600 seconds | Parsing large survey reports requires a long time. This duration can avoid timeout errors triggered before parsing is completed |
preserve_metadata | Enabled | Retain metadata such as line numbers and file generation time, for subsequent traceability and verification of retrieval results |
The parameter values provided on this page are all conventional recommendations, used as starting points for configuration. Actual values are affected by material form, data volume and business rules. Specific issues require specific analysis. It is recommended to test on your own samples before finalizing the settings.
Three common mistakes
- Phenomenon: Uploading files in the local front-end environment can parse content normally, but after packaging and deploying to the server, uploading documents results in a 404 error returned by the document parsing node, and the file content cannot be read. Cause: The server environment is not configured with read and write permissions for the file upload temporary directory, or the front-end request's file upload path does not adapt to the server domain name and port mapping rules.
- Phenomenon: After parsing a DOCX document containing equipment ledgers, the chunking result loses the binding relationship between equipment models and corresponding mileage, making it impossible to accurately match section information during retrieval. Cause: The
chunk_overlapconfiguration value is too small, failing to retain field associations between adjacent chunks, leading to separation of fields and parameters. - Phenomenon: After uploading a long document of the annual infrastructure plan type, the parsing task times out and fails, and no valid chunking result is generated. Cause: The
PARSE_FILE_TIMEOUT_SECONDSconfiguration value is too low, failing to adapt to the parsing time of large documents, or server resources are insufficient leading to parsing process interruption.
How to confirm the configuration is correct
- Upload a standard railway line survey DOCX document, check the parsed chunking results, confirm that each chunk contains complete section headings and corresponding parameter content.
- Upload documents in different formats (PDF, DOCX, TXT), verify that the parsing component can correctly recognize hierarchical headings and field information, with no content loss or format confusion.
- Simulate the server environment to upload large-size documents, confirm that the parsing task can be completed within the preset timeout period, with no timeout errors.
- Retrieve the test data set, verify that the chunking results can accurately match precise fields such as line numbers and stake numbers, with no context splitting issues.
Question material comes from public community discussions. Configuration values are common starting points and should be measured against your own samples. Verified on 2026-09-14.