View source for Lift and Escalator API

Network Rail's '''[https://portal.nr-lift-and-escalator.net/ Lift and Escalator API]''' was an API developed for Network Rail in 2020 by rail technology consultancy Hack Partners Ltd (now a rail AI software company, trading as CrossTech), nominally offering the real-time status of lifts and escalators at many locations across the rail network in Great Britain. The official documentation was quite sparse, hence this article was created by Peter in order to document the API unofficially.

'''This API was decommissioned on the 31<sup>st</sup> of January 2024, and replaced with [[Stations_Experience_API|a new API]].'''

== Transition ==
Transition to a [[Stations_Experience_API|new API]] began on the 17<sup>th</sup> of January 2024, with the CrossTech-maintained GraphQL and JSON APIs planned to be discontinued entirely on the 31<sup>st</sup>.

== Signing up ==
You can register for an account on the Lift and Escalator API [https://portal.nr-lift-and-escalator.net portal]. Once you've verified your email address, navigate to the "products" tab. Click on "Developer" in the list on this page, then create a new subscription with a name of your choosing. Now, navigate to "Profile", you should be able to see your keys.

== Access ==
Official documentation claims that V1 GraphQL functionality migrated to V2 doesn't require authentication, but this isn't entirely true. Some location information (e.g. postcode, toc) was broken out into a ''stations'' table, which is inaccessible while unauthenticated. The inclusion of station CRS codes in the assets table may render this table redundant.

== Data elements (V1) ==

The following data elements are held within the API:

{| class="wikitable"
|-
!Field
!v2 equivalent
!Description
|-
|uprn
|prn (asset)
|Unique asset identifier (not a [https://www.ordnancesurvey.co.uk/business-government/tools-support/open-mastermap-programme/open-id-policy UPRN])
|-
|sensorId
|sensorId (status or asset tables)
|A four-digit sensor identifier for the Electronic Monitoring Unit (EMU), left-padded with zeroes if required. 
|-
|blockId
|blockId (assets)
|An identifier for the location of the asset within a station
|-
|blockTitle
|
|The name of the location within the station
|-
|station
|name (station)
|Name of the station at which this asset is located
|-
|location
|location (asset)
|Name of the location within the station at which this asset is located
|-
|lat
|lat (station)
|Latitude in (WGS84)
|-
|long
|long (station)
|Longitude (WGS84)
|-
|postcode
|postcode (station)
|Postcode of the station in which this asset is located
|-
|route
|route (station)
|Network Rail [https://www.networkrail.co.uk/running-the-railway/our-regions/ Route] in which this asset is located
|-
|territory
|region (station)
|Network Rail [https://www.networkrail.co.uk/running-the-railway/our-regions/ Region] in which this asset is located
|-
|toc
|toc (station)
|Set to 'Managed Stations' for Network Rail Managed Stations, otherwise the name of the train operator
|-
|branch
|
|Unknown, but possibly the branch of the lift or escalator maintainer's organisation
|-
|type
|type (asset)
|Type of asset, e.g. Lift or Escalator
|-
|status
|status (status)
|Current status of the asset
|-
|isolated
|isolated (status)
|Indicates whether the asset is powered down or disconnected
|-
|engineerOnSite
|engineerOnSite (status)
|Indicates if an engineer has logged in to the sensor and is servicing the asset
|-
|independant
|independent (status)
|('''note the misspelling''' - independ'''ant''' in v1, independ'''ent''' in v2) Indicates if the lift is on [https://en.wikipedia.org/wiki/Elevator#Independent_service Independent Service] by use of a car preference key
|-
|updatedTime
|
|Date and time when the status was last updated
|}

== Tables (V2) ==
=== Asset ===
{| class="wikitable"
|-
!Field
!Official description
!Description
|-
|id
|Unique asset identifier
|Unique identifier (of asset?)
|-
|prn
|Asset property reference number
|Unique asset identifier, renamed from UPRN. '''This field cannot be used in the query builder.'''
|-
|stationNumber
|Asset number
| '''This field cannot be used in the query builder.'''
|-
|description
|
|e.g. "Colonnade Lift", "Lift 3,Platform 20"
|-
|displayName
|Standardised asset name
|e.g. "Lift to Colonnade ", "Lift, Platform 20"
|-
|sensorId
|Associated sensor
|A sensor identifier for the Electronic Monitoring Unit (EMU), '''no longer zero-padded'''
|-
|blockId
|
|An identifier for the location of the asset within a station
|-
|crs
|Associated station
|CRS code of the station at which this asset is located
|-
|location
|
|Name of the location within the station at which this asset is located (e.g. "Colonnade Lift", "Platform 20")
|-
|type
|Asset type (i.e Lift or Escalator)
|Type of asset, e.g. Lift or Escalator
|-
|inCommission
|
|'''This field cannot be used in the query builder. This field is not officially documented.''' Note that this bears a striking resemblence to the misspelled ''inCommision'' you can see in the query builder.
|-
|publicFacing
|
|'''This field is not officially documented.'''
|-
|status
|''relations not covered''
|(Relation) Current status of the asset
|}

=== Status ===
{| class="wikitable"
|-
!Field
!Official description
!Description
|-
|sensorId
|Unique sensor identifier
|ID of sensor
|-
|isolated
|
|Indicates whether the asset is powered down or disconnected
|-
|engineerOnSite
|
|Indicates if an engineer has logged in to the sensor and is servicing the asset
|-
|independent
|
|('''note that this is now not misspelled'''), indicates if the lift is in independent service mode.
|-
|status
|last status received
|Current status of the asset (e.g. "Available", "Unknown", "Not Available")
|-
|<s>lastUpdated</s>
|Time of last update to status
|'''Documented in v2 preview documentation, this field is completely absent'''.
|-
|asset
|''relations not covered''
|(Relation) Asset to which this status relates
|}

=== Stations ===
{| class="wikitable"
|-
!Field
!Official description
!Description
|-
|id
|Unique station identifier
|API-specific ID for station
|-
|crs
|Station CRS code
|CRS code of station asset is located at
|-
|name
|
|Name of station
|-
|lat
|
|Latitude in (WGS84)
|-
|long
|
|Longitude (WGS84)
|-
|toc
|Train operating company
|Set to 'Managed Stations' for Network Rail Managed Stations, otherwise the name of the train operator
|-
|region
|
|Network Rail [https://www.networkrail.co.uk/running-the-railway/our-regions/ Region] in which this asset is located
|-
|route
|
|Network Rail [https://www.networkrail.co.uk/running-the-railway/our-regions/ Route] in which this asset is located
|-
|postcode
|
|Postcode of the station in which this asset is located
|-
|address
|
|'''This field cannot be used in the query builder.'''
|-
|contactEmail
|
|'''This field cannot be used in the query builder.'''
|}

Note that stations are only available if you've authenticated using your bearer token, this includes using the query builder on the portal. If you are not authenticated, you'll see an error which makes it look like the table simply doesn't exist.

== Making a GraphQL request ==
All requests are through the API endpoint (https://nr-lift-and-escalator.azure-api.net/graphql/v2). Requests must be made via an HTTP POST request, navigating to this URL in a web browser will make an HTTP GET request, which will result in the following error:

<code>{"path":"$","error":"resource does not exist","code":"not-found"}</code>

The API uses [https://graphql.org/ GraphQL], which allows complex queries to be submitted in an HTTP POST request.  A query is just a JSON data structure with some fields to filter on, and other fields to return.

== REST API ==
With V2 came the introduction of a handful of REST endpoints, these are
* <code>https://nr-lift-and-escalator.azure-api.net/api/v2/sensors[?num][&offset]</code> - All statuses, essentially equivalent to a graphQL query for statuses with no joins.

Num and offset aren't documented; they're used for paging, with num defining the limit, and offset defining the offset. Both are nominally optional, but num will default to 50 if unset. Instead of paging through these, there's no upper limit to ''num'', if you set it to 20000, you'll get all statuses at once.

* <code>https://nr-lift-and-escalator.azure-api.net/api/v2/sensors/{id}</code> - Statuses by sensor ID, same columns as graphQL status table
* <code>https://nr-lift-and-escalator.azure-api.net/api/v2/stations/{crs}/assets</code> - Assets marked as being at given station CRS

Note that you need to provide bearer authentication for this, since it's passed through to GraphQL.

* <s><code>https://nr-lift-and-escalator.azure-api.net/api/v2/assets/{id}</code></s> - Get asset information by asset ID (broken)

<code>{"error":"field 'uprn' not found in type: 'assets'","path":"$.selectionSet.assets.selectionSet.uprn","code":"validation-failed"}</code>

== Simple requests ==

=== All assets at a station (V1) ===

To return the status of all lifts and escalators at a particular station, such as Edinburgh Waverley:

<pre>query MyQuery {
  status(where: {station: {_eq: "Edinburgh Waverley"}}) {
    blockTitle
    branch
    engineerOnSite
    independant
    isolated
    lat
    location
    long
    postCode
    route
    sensorId
    station
    status
    territory
    toc
    type
    updatedTime
    uprn
    blockId
  }
}</pre>

=== All assets at a station (V2) ===
<pre>
query {
    assets(where: {crs: {_eq: "EDB"}}) {
        blockId
        crs
        description
        displayName
        id
        location
        sensorId
        status {
            engineerOnSite
            independent
            isolated
            sensorId
            status
        }
        type
    }
}
</pre>

=== All assets at all stations (V2) ===

<pre>query {
	assets {
		blockId
		crs
		description
		displayName
		id
		location
		sensorId
		status {
			engineerOnSite
			independent
			isolated
			sensorId
			status
		}
		type
	}
}</pre>

=== Stream of updates ===

It is supposedly possible to make an API request and receive a stream of updates using the <code>@live</code> directive on the GraphQL query, but does not seem to work on this API.

== Room for improvement (V1) ==

There is some room for improvement on the API:

* '''Null entries''' - some fields are set to "#N/A", and some are set to null
* '''Unmapped sensors''' - there are instances (such as sensorId 3104) where no data has been filled in about the asset at all
* '''No escalators''' - some escalators are included but fall fully within the problem above, all have null locational data
* '''Incorrect references to territories''' - the term 'territory' was in use during Railtrack days, but is no longer used - Region and Routes are the current terminology
* '''Out-of-date TOC information''' - sensor 4052 refers to London Midland, sensor 3082 refers to East Coast, and 6148 to Arriva Trains Wales - none of whom currently operate franchises
* '''Lack of machine-interpretable data''' - sensor 5006 is described as 'Wolverhampton Stn Lift/Escalator 05', in location 'Passenger Lift Platform 4', whereas sensor 8127, 'Imperial Wharf Stn Lift/Escalator 01' is in location 'Platform 1' - these are not easy to parse and necessarily link to a particular platform
* '''Non-passenger assets''' - 1032 and 4034 are lifts situated in the South Wales and Thames Valley signalling centres, respectively. 1041 is "Mepham Street Goods No. 2" at London Waterloo, and 5054 will take you to "[https://en.wikipedia.org/wiki/Red_Star_Parcels Red Star Parcels]" in Milton Keynes

== Official documentation ==
Links to official documentation

=== Version 2 ===
* [https://docs.google.com/document/d/18IWzcjuuj6usxEv6pIRjH39EOouDFyIzk9nTXUP7ymE/edit Lifts & Escalators (LNE) API V2 - Usage Instructions] - overview, registration, creating API subscription, obtaining bearer token
* [https://docs.google.com/document/d/1Aikq_JzP2FvZkIJkKCBNahqIA0HdGwcSQUQUTP6oFY4/edit V2 API Authentication Docs] - creating API subscription, obtaining bearer token
* [https://docs.google.com/document/d/e/2PACX-1vTBUhyCXJoCvKUdIjE5GSyV3CqPgXg5d4K7DAghGilat4j8DTlWwMaTIQwTee-zvifFuW4NVB_0Hd5S/pub Documentation - Lifts & Escalators API v2 (developer preview)] - Types, endpoints, responses, example queries
* [[:File:Nr_lift_escalator_api_introspected_schema_2023-09-09.txt|Introspected GraphQL schema (2023-09-09)]] - Not provided officially (documentation claims that introspection has been disabled)
=== Version 1 ===
* [https://docs.google.com/document/d/e/2PACX-1vQEcL1yJLUVd8IAKGHi0s2cRsbKuedxuT2YT7b1TNnmjUi07_U15feiVWNlTGEzva7xoTiMrt4AcmE3/pub Documentation - Lifts & Escalators API (public preview)]