API Reference

Conventions

Format: JSON. Live snapshots are stored gzip-compressed; request the latest-plain.json variant for an uncompressed body.
Railway day: historical dates use the London railway day, which runs 03:00–02:59. A YYYY-MM-DD refers to that boundary, not midnight.
Freshness: live snapshots rebuild roughly every 30–60 seconds and are served no-store. Historical and timetable responses are cacheable.

Live snapshots

The primary feed. Each line's Durable Object publishes a pre-built snapshot; these endpoints read the latest one.

GET /live/{lineId}/map/latest.json

Latest map-area snapshot for a line — a superset that includes adjacent services shown on the app's map. gzip-compressed. Use /map/latest-plain.json for an uncompressed body.

GET /live/{lineId}/line/latest.json

Latest single-line snapshot including terminals. /line/latest-plain.json for uncompressed.

GET /live/{lineId}/{map|line}/latest-stats.json

Metadata and stats only — train count, build time, source health. Omits the trains[] array. Ideal for lightweight status polling.

GET /live/{lineId}/{trainNumber}/latest.json

Single-train lookup. ?flavor=map|line selects which snapshot to search (default line).

GET /live/all/line/latest.json

All lines merged into one response. Only the line flavour exists for all.

Response shape

{
  "as_of": "2026-07-07T18:48:49Z",
  "status": { "ok": true, "buildMs": 142 },
  "stats":  { "trainCount": 34 },
  "trains": [ /* Train objects — see the data model below */ ]
}

If no snapshot exists yet, the endpoint returns 202 with a warming body and triggers a build; retry shortly.

Journeys & units

Per-train and per-unit history for a railway day. Requests older than a key's historical window are gated.

Endpoint	Returns
`GET /live/{lineId}/journeys`	All journeys for today's railway day.
`GET /live/{lineId}/journeys/{trainNumber}`	One train's journey. `?timetable=true` folds in the booked working-timetable trip.
`GET /live/{lineId}/journeys/{YYYY-MM-DD}`	All journeys for a historical railway day.
`GET /live/{lineId}/journeys/{YYYY-MM-DD}/{trainNumber}`	A single historical journey.
`GET /live/{lineId}/journeys/{trainNumber}/compare`	Timetable-vs-live comparison. `?date=YYYY-MM-DD`.
`GET /live/{lineId}/units`	All physical units seen on a railway day. `?date=`.
`GET /live/{lineId}/units/{unitNo}`	One unit: its `journeys[]` and `gapSightings[]`.

Journey shape

{
  "trainNumber": "460",
  "railwayDay": "2026-07-07",
  "stops": [
    { "time": "18:41:00", "location": "Baker Street", "platform": "5", "direction": "northbound" }
  ]
}

Stations

{code} is a station registry code (e.g. WPK for Wembley Park).

Endpoint	Returns
`GET /station/{code}`	Station info: `{code, name, lines[], timetableAvailable}`.
`GET /station/{code}/board`	Live departure board across all lines serving the station. `?limit` (default 10, max 50).
`GET /station/{code}/timetable`	Scheduled departures. `?direction`, `?from`/`?to` (HH:MM).
`GET /station/{code}/departures`	Merged live + scheduled board, with a booked-platform signal.
`GET /station/{code}/history`	Past sightings. `?date=YYYY-MM-DD` (required), `?from`/`?to`.

Board shape

{
  "station": "Wembley Park",
  "code": "WPK",
  "asOf": "2026-07-07T18:48:49Z",
  "departures": [{
    "lineId": "metropolitan",
    "trainNumber": "460",
    "towards": "Aldgate",
    "direction": "southbound",
    "currentLocation": "Approaching Wembley Park",
    "secondsAway": 90,
    "stopsAway": 1,
    "platform": "3",
    "platformInfo": { "number": "3", "source": "confirmed-location", "confidence": "high" },
    "stoppingPattern": "All Stations"
  }]
}

secondsAway is an estimate — a live ETA rebased onto the train's true position; null when timing data is missing.
stopsAway is a topological stop count; null when the branch is ambiguous.
platformInfo.source is one of five ranked signals, strongest first: confirmed-location, polled, … , scheduled.

Timetables

Working-timetable data. Currently published for the Metropolitan and Chiltern lines.

Endpoint	Returns
`GET /timetables/{lineId}/{dayType}/{direction}`	Timetable for a line, day type and direction. `?date=` override.
`GET /timetables/{lineId}/{timetableId}/{dayType}/{direction}`	A specific timetable version.
`GET /timetables/{lineId}/list`	Available timetable IDs for a line.
`GET /timetables/{lineId}/{YYYY-MM-DD}`	The schedule entry effective for a date.

dayType is one of m-f, sat, sun, current; direction is northbound or southbound.

Replay archive

Archived historical snapshots. Only the map flavour is archived.

Endpoint	Returns
`GET /replay/{lineId}/list`	Archived snapshot keys for a day. `?day=YYYY-MM-DD`, `?flavor=map`.
`GET /replay/get?objectKey=…`	Fetch one archived snapshot by object key.

Object keys follow archive/{lineId}/trains/map/{YYYY-MM-DD}/{HH}-{MM}-{SS}.json and are validated to prevent traversal. Snapshots older than a key's window require a pro/admin key.

Release history public

GET /releases

Public component release history — returned as a page, or JSON with ?format=json.

Status & health

Endpoint	Returns
`GET /admin/status`	`{ now, overall: "ok"\|"degraded", monitorStatus, lines[] }` — per-line up/down, tuned for uptime monitors.
`GET /admin/health`	Adds deploy `version` and per-line `meta` (last build, train count, consecutive failures).
`GET /live/{lineId}/{map\|line}/latest-stats.json`	Per-line freshness and stats without the train list.

These endpoints power this site's status page, which reports per-line pipeline health.

The Train object

The record emitted in every live snapshot's trains[] array. Selected fields:

Field	Type	Meaning
`id`	string	Unique id, `lineId:trainNumber`.
`lineId`	string	Line slug.
`trainNumber`	string	LU train number or NR headcode. `trainNumberInferred` flags inference.
`source`	`trackernet` \| `unified`	Which upstream feed produced the record.
`currentLocation`	string	Live positional text, e.g. `"At Baker Street Platform 5"` or `"Between X and Y"`.
`direction`	string	Cardinal direction, e.g. `northbound`.
`towards` / `nextTowards`	string	Destination(s).
`stoppingPattern`	string	e.g. `All Stations`, `Semi Fast`, `Fast`, `Booked: …`.
`leadingCarNo` / `rearCarNo`	string	Physical unit identifiers.
`isMaybeStalled`	boolean	Stall inference; paired with `stallDurationSeconds`, `stallSince`.
`isReformed` / `oldTrainNumber`	—	Reformation tracking.
`polledStationName`	string	Station whose countdown produced this sighting — not reliably the next stop (see data sources).

Errors & status codes

Code	Body	Meaning
`200`	JSON body	Success.
`202`	warming	No snapshot built yet; a build was triggered. Retry shortly.
`404`	HTML error page	Unknown path (paths are gated by an allow-list).

✉️

Endpoints evolve with the app. If something here doesn't match what you're seeing, or you need access, email [email protected].