What the data for this category looks like
Railway and highway investment research data mainly comes from public statistical bulletins of the National Railway Administration and the Ministry of Transport, monthly operation ledgers of road network operating enterprises, line operation and maintenance detection logs, engineering bidding announcements, and line design drawings. Data update rhythms fall into three categories: monthly operation reports are updated each month, operation and maintenance detection logs are updated daily or in real time according to work cycles, and engineering documents and bidding announcements are released irregularly. Document structures include three types: structured parameter tables, unstructured detection reports, and line design drawings. They contain specialized fields such as total route extension mileage, traction tonnage, and window maintenance duration. All units use the metric system.
Constraints Imposed on Multi-turn Dialogue and Prompt Engineering by These Characteristics
The specialized fields of railway and highway investment research data are numerous, document types are varied, and update frequencies differ greatly. This places clear constraints on multi-turn dialogue and prompt engineering configurations. Multi-turn dialogue must retain key identifiers such as line IDs and detection dates within the context to avoid confusion between operation data of different road sections. Prompt engineering must adapt to specialized terminology and dedicated fields. It must explicitly require the AI to prioritize the latest uploaded operation data, and verify unit consistency to prevent result deviations caused by mixed use of metric and imperial units. In addition, prompt engineering must specify the parsing format for unstructured drawings and reports to ensure the AI can accurately extract core indicators such as defect levels and traffic volume.
How to Set Configurations
| Configuration Item | Recommended Value | Rationale |
|---|---|---|
maxContext | 12000–15000 characters | Railway and highway investment research data includes multiple route ledgers and detection reports. A long context can retain key fields such as route IDs and detection dates, preventing context loss during multi-turn dialogue |
system_prompt_template | Calibrated based on actual testing | Must adapt to specialized railway and highway fields such as total route extension mileage and traction tonnage. Add constraints such as "prioritize the latest provided operation data" and "uniformly use units specified in documents" in the template |
RECALL_TOP_N | Top 8–10 entries | Investment research data contains multi-dimensional indicators. Retrieving too many entries leads to redundancy, while retrieving too few misses key route parameters. This setting adapts to multi-index retrieval needs for railway and highway specialized segments |
SIMILARITY_THRESHOLD | 0.75–0.85 | There are many specialized terms in railway and highway fields. A threshold that is too low recalls irrelevant route data, while a threshold that is too high misses associated information for similar road sections |
UPLOAD_FILE_MAX_SIZE | 2000 MB | Document packages containing line design drawings and annual operation and maintenance reports have large file sizes. This setting adapts to the large-file upload needs of this category |
PARSE_FILE_TIMEOUT_SECONDS | 600 seconds | Parsing large engineering drawings and batch detection reports takes a long time. Reserving sufficient parsing time prevents task interruptions |
The parameter values provided on this page are all conventional recommendations used as a starting point 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 settings.
Three Common Mistakes
- A pop-up stating "No permission to operate this conversation record" appears in the dialogue interface. The cause is that the knowledge base bound to the multi-turn dialogue has not granted access permissions to the current session user. Context-associated knowledge base entries cannot be read.
- The AI replies with "No files uploaded", even though the document parsing requirement is embedded in the system prompt. The cause is that the document referenced in the system prompt has not been associated via the FastGPT knowledge base upload module. It is only embedded as text without establishing a retrieval association.
- After upgrading to version 4.9.0 and refreshing the dialogue page, a new dialogue is displayed and historical records cannot be loaded. The cause is that the local session cache directory permissions are reset after the version upgrade, making it impossible to read stored data corresponding to historical session IDs.
How to Confirm the Configuration Is Correct
- Initiate a multi-turn dialogue that includes a specific route ID and detection date. Verify that subsequent questions do not require repeated input of key information to obtain accurately associated results.
- Upload a railway line detection report. Specify the extraction of defect level and traffic volume indicators in the system prompt. Verify that the AI can correctly recognize specialized terminology and output corresponding content.
- Upload an operation and maintenance report compressed package with a volume exceeding 1000 MB. Verify that the upload and parsing processes do not have timeout errors.
- Adjust
SIMILARITY_THRESHOLDto a range lower than 0.75. Retrieve data for similar road sections. Verify that the relevance of the recalled results meets expectations.
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.