ETCS LS and 1+2

[MatisseBE]

Two question:

1. In Belgium's implementation of ETCS, there are plenty of track on which only ETCS L1 limited supervision is possible. Do we want to tag this separately? It has quite big implications such as requiring light signals.

2. There are lines (E.g.: HSL 4 - tagged: railway;etcs | 1;2) equipped with both ETCS L1 and L2. Other lines have ETCS 1 OR 2 with the old system as the backup. The tagging only shows it having L2, and it is displayed as such too. Is this expected behaviour? Can we display lines with both 1+2 as a different category/color?
   (https://openrailwaymap.fly.dev/#view=13.9/51.33992/4.60641&style=signals)

[TheSikal]

For the ETCS Level 1 Limited Supervision, changing the tagging scheme to something like railway:etcs=[1LS|1FS|2|yes|no] can be suggested.

The question of rendering multiple values also concerns lines with multiple train protection systems (often ETCS and a class B TPS such as TVM or LZB). It would be interesting to show all values in popup but I don't know if it is possible to render them on the map while keep it readable.

[hiddewie]

The current configuration is defined in

OpenRailwayMap-vector/features/train_protection.yaml

Lines 49 to 67 in b13e973

	- train_protection: etcs
	tags:
	- { tag: 'railway:etcs', value: 'yes' }
	- train_protection: etcs_1
	tags:
	- { tag: 'railway:etcs', value: '1' }
	- train_protection: etcs_2
	tags:
	- { tag: 'railway:etcs', value: '2' }
	- train_protection: etcs_2
	tags:
	- { tag: 'railway:etcs', value: '1;2' }
	- train_protection: etcs_2
	tags:
	- { tag: 'railway:etcs', value: '3' }

. Theorerically we could differentiate many more types of ETCS level / sub-level tagging in the coloring of the lines by splitting more categories.