Proposal:Platform exits

Platform exits
Proposal status:	Draft (under way)
Proposed by:	Kylenz
Tagging:	exit:carriages=* destination:carriages=* destination:carriages:*=* destination:*:carriages=*
Applies to:
Definition:	Indicates which carriage of a subway/train is closest to the platform exit
Statistics:
Draft started:	2024-02-13
RFC start:	2024-02-13

Rationale

Some train platforms only have an exit on one end of the platform, which means people might need to walk a long distance down the platform if they arrive in the wrong carriage.

exit:carriages=* indicates which carriage of a train is the closest to the exit when arriving at the station, to avoid a long walk down the platform to the exit or elevator.

The type of exit (stairs, escalator, or lift) can also be specified, so that routing software can suggest a different carriage for users who need a wheelchair-accessibile route.

Proposal

The tag works similarly to *:lanes=*. Instead of lanes, each carraiage is separated by a | character, starting from the first carriage that passengers can use at front of the train, although more complex scenarios are allowed.

How to map

The tag(s) should be used on public_transport=stop_position nodes, which should also have a ref=* tag so that data consumers can match the OSM data to an external dataset such as GTFS.

There are two approaches:

1. Fixed number of carriages

Use this tagging style:

• If all trains that stop here have the same number of cars; or
• If you only want to define data for trains with a specific number of cars.

This simplest option is to use yes/no. yes means that an exit is located next to that carriage.

For example, exit:carriages=no|no|yes|yes defines the arangement for a 4-car train. Here, it would be smarter to travel in the last 2 carriages if you want to avoid walking down the platform.

To provide more useful information, you can specify the type of exit instead of using yes. Other values include stairs, escalator, or lift.

For example: exit:carriages=lift;stairs|no|no|no|no|stairs. In this case, it would be smartest to travel in the 1st carriage if you need the lift. If you can use the stairs, then the 1st or 6th carriage would be best to minimise walking time.

no, none, and (blank) can be used interchangably, but no is preferred.

2. Flexible number of carriages

Use this tagging style:

• if trains with different carriage lengths stop here, but they always align themselves to the same point at the front, middle, or rear of the platform.

Counting from the front of the train:

• use the same tagging style as above, but end the value with |....
• Example: exit:carriages=none|stairs|....
• This means: There is no exit next to the first car and there are stairs next to the second car.

Counting from the rear of the train:

• Use the same tagging style as above, but start the value with ...|.
• Example: exit:carriages=...|stairs|none.
• This means: There is no exit next to the last car and there are stairs next to the second-last car.

Counting from the middle of the train:

• Use the same tagging style as above, but start the value with ...| and end the value with |....
• Example: exit:carriages=...|stairs|stairs|....
• This means: There are stairs next to the middle 2 cars of the train.

Bidirectional platforms

If a platform supports bidirectional operation, you can use exit:carriages:forward=*, where *:forward=* refers to the direction of the way. If someone reverses the way, editors like iD will automatically flip the *:forward=* or *:backward=* tags so they remain correct.

Examples

• 

  In this example of an 8-car train, the lift is located next to 4th car, while the escalators are located next to the 3rd car. There are stairs at two locations along the platform. This would be tagged as exit:carriages=no|no|escalator|stairs;lift|stairs|no|no|no

• 

  exit:carriages=stairs|stairs|stairs|no|no|stairs|stairs|stairs;lift

Limitations

This tagging system will be too limited for many scenarios. The defintion was written based on how the tag is used in one city.

Destinations

At some (modern) train stations, all exits from a platform lead to the same concourse area, so it doesn't matter what exit you take. In these cases, you don't need this tag.

At other stations, you need to walk to a specific point along the platform to find the right exit. destination:carriages=* can be used to define which exit is closest to each carriage of the train.

Destination tags follow the same system as destination:*:lanes=*, except that lanes is replaced with carriages.

Examples of destinations

• 

  exit:carriages=stairs|stairs|stairs|no|no|stairs|stairs|stairs;lift
  destination:ref:carriages=1|1|1|none|none|2|2|2
  destination:carriages=Bathurst St|Bathurst St|Bathurst St|||Liverpool St|Liverpool St|Liverpool St

See Also

• access:carriages=* - if you're forced to use a certain carriage because of the train is too long to fit on the platform.
• carriage=* - an unrelated mode of transport with a confusingly similar name

Use cases

• There are several apps in New York City and Sydney which use proprietary data to show the 'best carriage' to ride in (exitstrategynyc.com, citymapper nyc, ...)
• In New York City, some subway cars show this data on interior screens
• In Tokyo, this type of data is published online
• In Toronto, there are unofficial infographics which convey this information
• In London, there is an app for this purpose

Rendering

No

Features/Pages affected

• Key:exit:carriages
• Key:destination:carriages
• Key:destination:ref:carriages

External discussions

• OSM US Slack 13/02/2024

Comments

Please comment on the discussion page.