Proposed features/dual voltage electrification

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Garry Keenor
Status: Draft (under way)
Proposed by: GazzerK
Tagging: electrified=contact_line;rail, contact_line;4th_rail
Applies to: nodeway
Definition: A track electrified with two different electrification systems; such as overhead contact line and 3rd rail
Drafted on: 2020-06-xx
RFC start: 2020-06-xx

Proposal

Ashford International station in the UK, showing 25kV AC overhead contact line and 750V DC 3rd rail on a single track.

It is proposed that the current railway tags electrified=*, frequency=* and voltage=* are collectively used to identify tracks which are electrified using two different electrification systems. These are typically found at the interfaces between two routes electrified with different systems.

Rationale

The current electrifed=* tag is designed to capture the railway electrification contact system in use; the frequency=* tag identifies the contact system frequency in Hertz, and the voltage=* tag identifies the contact system voltage. This assumes a single system for each track - which is usually the case.

However at some locations the different systems meet and overlap, with an overhead contact system and a ground-level contact system co-existing on a single track.

There is currently no guidance given to taggers on how to treat these tracks. This proposal aims to use the standard OSM key=<value1;value2> syntax to identify these tracks, and to provide guidance to taggers in tagging dual voltage areas.

Examples

Many countries around the world have more than one electrification system in place, and there are typically a small number of interface locations where those systems meet and co-exist.

Tagging

Proposed tagging is as follows - proposal in bold. The whole of the electrified=* tagset is shown for context.

Key Value Property Description Default value
electrified yes Electrified - system not specified This tag is to be used when the system of electrification is unknown. Mappers should use electrified=contact_line, 3rd_rail, 4th_rail, or ground-level_power_supply where they are able to indentify the system by use of aerial imagery or other means.
no Not electrified Used for non-electrified tracks.
contact_line Contact line Used for tracks electrified with Overhead Contact Line (OCL) / Overhead Contact System (OCS) / Overhead Line Equipment (OLE)
rail 3rd contact rail Used for tracks electrified with a 3rd rail system, with one additional rail on insulators, using shoe pickup by the train, and traction return via the running rail(s)
4th_rail 4th contact rail Used for tracks electrified with a 4th rail system, with two additional rails on insulators and two shoe pickup by the train, and traction current returning via one of the insulated rails
ground-level_power_supply Ground-level power supply Used for tracks electrified with ground-level power supply on Wikipedia.
contact_line;rail Dual electrified - overhead contact line and 3rd rail Used for a single track electrified with both Overhead Contact Line (OCL) and 3rd rail.
contact_line;4th_rail Dual electrified - overhead contact line and 4th rail Used for a single track electrified with both Overhead Contact Line (OCL) and 4th rail.
voltage <voltage in Volts> Voltage Voltage of the railway electrification system. Current Systems on Wikipedia. For dual electrified areas, use overhead contact line voltage, followed by 3rd or 4th rail voltage. For instance, a track electrified with both 25000V 50Hz overhead contact line and 750V DC 3rd rail would be tagged voltage=25000;750
<OCL voltage in Volts;3rd or 4th rail voltage in Volts> OCL and 3rd or 4th rail voltages in dual electrified areas |
frequency <frequency in Hertz> Voltage Voltage of the railway electrification system. Current Systems on Wikipedia. For dual electrified areas, use overhead contact line voltage, followed by 3rd or 4th rail voltage. For instance, a track electrified with both 25000V 50Hz overhead contact line and 750V DC 3rd rail would be tagged voltage=25000;750
<OCL frequency in Hertz;3rd or 4th rail frequency in Hertz> OCL and 3rd or 4th rail frequencies in dual electrified areas Frequency of the railway electrification system. Use 0 for direct current. More information. For dual electrified areas, use overhead contact line voltage followed by 3rd or 4th rail voltage. For instance, a track electrified with both 25000V 50Hz overhead contact line and 750V DC 3rd rail would be tagged frequency =50;0

Applies to

All and part of a way tagged with railway=rail.

Rendering

This proposal provides a handle for renderers to refine rendering for dual electrified areas.

Features/Pages affected

Additions to wiki pages and tables about railways. This proposal does make any changes to current electrified railways except for those dual electrified locations which are currently erroneously tagged as having a single system.

External discussions

Discussion of the proposed change with the Open Rail Map group.

Comments

Please comment on the discussion page.