Car Actually Placed Webhook - Cedar.AI Documentation

Event Overview

The Car Actually Placed webhook fires when a railcar is physically placed at a station or track in your network. It delivers equipment details, the placement location, loaded/empty status, and the associated work order (if any).

This webhook is triggered through ARMS workflow automation. Configure it in your workflow rules to notify external systems when cars arrive at specific locations.

Payload Schema

{
  "event_type": "car_actually_placed",
  "event_timestamp": "2026-03-05T14:30:00+00:00",
  "work_order_id": "12345",
  "linked_resources": {
    "equipment": [
      {
        "resource_id": 123,
        "car_number": "GCGO 12345"
      }
    ],
    "event_station": {
      "resource_id": 456,
      "grouping_type": "station"
    }
  },
  "attributes": {
    "is_loaded": true
  },
  "actor": {
    "resource_type": "User",
    "resource_id": 12345,
    "display_name": "ops@customer.com"
  }
}

Field Reference

Top-level Fields

Field	Type	Required	Description
`event_type`	string	Yes	Always `"car_actually_placed"` for this event.
`event_timestamp`	string (ISO 8601)	No	When the event occurred. `null` if unavailable.
`work_order_id`	string	No	ID of the associated work order. `null` if the event has no work order.
`linked_resources`	object	Yes	Equipment and station involved in the event.
`attributes`	object	Yes	Event-specific attributes.
`actor`	object or null	Yes	Who caused the triggering event. `null` for system-initiated events. See Shared Payload Fields -> actor.

linked_resources.equipment

An array of equipment items being placed. Always an array, even for a single car.

Field	Type	Description
`resource_id`	integer	Internal equipment identifier.
`car_number`	string or null	Railroad car number (e.g. `"GCGO 12345"`).

linked_resources.event_station

The station or track where the equipment is being placed. null if no station is associated.

Field	Type	Description
`resource_id`	integer	Internal station identifier.
`grouping_type`	string	Type of location (e.g. `"station"`, `"track"`).

attributes

Field	Type	Description
`is_loaded`	boolean	`true` if the car is loaded, `false` if empty.

Example HTTP Request

This is the full HTTP request your endpoint receives:

POST /your-webhook-endpoint HTTP/1.1
Content-Type: application/json
X-Webhook-Timestamp: 1709651400
X-Webhook-Signature: <base64-encoded-ed25519-signature>
X-Webhook-KeyId: cedar-webhooks-2026
X-Webhook-Id: 550e8400-e29b-41d4-a716-446655440000

{"actor":{"display_name":"ops@customer.com","resource_id":12345,"resource_type":"User"},"attributes":{"is_loaded":true},"event_timestamp":"2026-03-05T14:30:00+00:00","event_type":"car_actually_placed","linked_resources":{"equipment":[{"car_number":"GCGO 12345","resource_id":123}],"event_station":{"grouping_type":"station","resource_id":456}},"work_order_id":"12345"}

The JSON body is canonically serialized (sorted keys, no extra whitespace) so the signature can be verified deterministically. See the Webhook Overview for verification instructions.

Setting Up This Webhook

Configure Workflow

In ARMS, create or edit a workflow rule that triggers on car placement events.

Add Webhook Effect

Add the Car Actually Placed Webhook effect to the workflow. Provide your endpoint URL.

Implement Your Endpoint

Build an HTTPS endpoint that receives the POST, verifies the signature, and processes the event.

Test

Trigger a test event and confirm your endpoint receives and verifies the payload correctly.

Webhook Overview

Signing, verification, public key, and shared HTTP headers.

​Event Overview

​Payload Schema

​Field Reference

​Top-level Fields

​linked_resources.equipment

​linked_resources.event_station

​attributes

​Example HTTP Request

​Setting Up This Webhook

​Related

Webhook Overview

Event Overview

Payload Schema

Field Reference

Top-level Fields

linked_resources.equipment

linked_resources.event_station

attributes

Example HTTP Request

Setting Up This Webhook

Related