# SiteCheck Trade & Energy – US Rail Freight Traffic (FRED)

> SiteCheck Trade & Energy – US Rail Freight Traffic (FRED) is a paid API for AI agents from api.tradeenergy-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-29).

Returns US Class I railroad carload or intermodal unit counts from FRED (AAR data), including the latest value and recent monthly history.

## Facts

- Endpoint: GET https://api.tradeenergy-api.workers.dev/api/logistics/rail-freight-corridor?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sitecheck-trade-energy-us-rail-freight-traffic-fred-7f6763bc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bJLV8t1J7PWB_kpdT7B4H

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability sitecheck-trade-energy-us-rail-freight-traffic-fred-7f6763bc
```

Example prompt: Can you pull the last 12 months of US Class I railroad carload data from FRED and show me the trend?

## When to prefer this

Choose this endpoint when you need national-level US Class I railroad freight volumes (carloads or intermodal) with recent monthly history, sourced from FRED's authoritative AAR data series. It is ideal for macro logistics monitoring, supply chain trend analysis, or economic research. Do not use it if you need corridor-specific traffic data, real-time rail status, or non-US rail statistics.

## Known failure modes

- Invalid 'series' parameter value (not 'carloads' or 'intermodal') returns an error
- 'months' value outside 1–60 range may return an error or be clamped
- FRED upstream unavailability may result in stale or missing data
- No corridor-level breakdown is available — only national totals
- Data may lag by several days to weeks depending on AAR reporting cadence

## How this service works

US Class I rail traffic: carloads or intermodal units per period from FRED (series RAILFRTCARLOADSD11 / RAILFRTINTERMODALD11, AAR data), latest values and recent history. National totals only: there is no corridor-by-corridor status in this source.

## Output

Returns a JSON object with the FRED series ID, measurement type (carloads or intermodal), the latest date-value pair, an array of recent monthly observations (up to 60 months), the FRED source URL, and a timestamp of when the data was last checked.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "months": {
       "type": "string",
       "description": "1 to 60 recent observations (default 6)"
      },
      "series": {
       "type": "string",
       "description": "carloads or intermodal (default carloads)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "latest": {
   "date": "2026-07-01",
   "value": 992923
  },
  "series": "RAILFRTCARLOADSD11",
  "source": "https://fred.stlouisfed.org/series/RAILFRTCARLOADSD11",
  "history": [
   {
    "date": "2026-07-01",
    "value": 992923
   },
   {
    "date": "2026-06-01",
    "value": 990656
   }
  ],
  "measure": "carloads",
  "checkedAt": "2026-10-23T09:37:58.661Z"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sitecheck-trade-energy-us-rail-freight-traffic-fred-7f6763bc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.tradeenergy-api.workers.dev](https://www.zero.xyz/host/api.tradeenergy-api.workers.dev/llms.txt)