HTTP Interfaces and External Systems for Railway and Highway

What the Data Looks Like

Railway and highway research report data originates from public disclosure reports of transportation industry associations, railway and highway operating entities, and monthly operational data published by official statistical agencies. Two update schedules are used: regular and ad-hoc. Regular updates release core operational data and industry analysis on a monthly or quarterly basis. Ad-hoc special reports are published when major infrastructure projects open or policies are adjusted.

Document structures include structured operational fields and unstructured analysis content. Structured fields include route mileage, freight volume, passenger-kilometers traveled, and more. Corresponding units are kilometers, ten thousand tons, and hundred million passenger-kilometers. Metadata fields such as publishing institution, publication date, and report rating are also included.

Constraints for HTTP Interfaces and External Systems

Multi-source data with inconsistent update schedules requires interfaces to support filtering by publication date and report type. Interfaces must also support incremental pulling to adapt to different update cycles.

Clear field and unit requirements mandate that interfaces return original metadata fields and their associated units. This prevents data distortion from automatic conversion.

Document structures combining structured operational data and unstructured analysis content require interfaces to support both full-text retrieval and structured field retrieval. This meets query needs for diverse business scenarios.

Regionalized report content requires interfaces to support filtering by jurisdiction. This aligns with the business scope requirements of external systems.

Configuration Settings

Configuration Item	Recommended Value	Rationale
`rag_recall_topk`	10-15 results	Railway and highway research reports include multi-dimensional structured fields and analysis content. This recall range covers core retrieval needs
`parse_chunk_size`	800-1200 characters	Research reports contain long paragraphs of policy interpretations and operational analysis. This chunk length preserves context integrity
`api_timeout`	600 seconds	Parsing and retrieval of some in-depth research reports require longer durations. This avoids truncation of complete content due to timeout
`filter_by_metadata`	Enabled	Retrieval results must be filtered by metadata such as publication date and route type to meet external system filtering requirements
`return_raw_metadata`	Enabled	Raw unit information for fields such as freight volume and passenger-kilometers traveled must be retained. This prevents data format distortion
`api_max_request_per_minute`	Determined via actual testing	Railway and highway research reports have low update frequencies. High concurrent request volumes are not necessary

The parameter values provided on this page are common starting points for configuration. Actual values are affected by material format, data volume, and business rules. Specific scenarios require individual analysis. It is recommended to test on your own samples before finalizing settings.

Three Common Misconfigurations

Issue: Interface returns 504 Gateway Timeout error. Cause: api_timeout is not set to a value matching research report parsing durations. This truncates in-depth research reports before parsing completes.
Issue: Unit display for the freight volume field in retrieval results is abnormal. Cause: return_raw_metadata is not enabled. This causes the system to automatically convert the original unit field.
Issue: Target research reports cannot be filtered by publication date. Cause: filter_by_metadata is not enabled, or the publish_date field is omitted from request parameters.

How to Confirm Proper Configuration

Send an interface request that includes the publish_date parameter. Verify returned results only include research reports within the specified date range. This confirms the filter_by_metadata configuration is active.
Upload a railway or highway research report to the parsing interface. Verify returned metadata includes original fields such as freight volume and passenger-kilometers traveled, along with their corresponding units. This confirms the return_raw_metadata configuration is active.
Send a retrieval request containing long-text analysis content. Verify no timeout error is returned. This confirms the api_timeout configuration matches actual parsing durations.
Send a batch retrieval request. Verify the number of returned recall results matches the preset configuration. This confirms the rag_recall_topk configuration is active.
Verify corresponding configuration items are correctly loaded in FastGPT 4.14.4 or later versions.

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.