Update US signal rendering

[detective-fiasco]

This is a draft of a pull request in collaboration with user @The3dVehicleguy.

It will add more icons and more detailed rendering of US signals.

This PR is complete. Detailed description of this PR is here: #952 (comment)

[RailandSea]

I have a few signal icons that might work just need to get it resized right.

[detective-fiasco]

I have a few signal icons that might work just need to get it resized right.

@RailandSea it would be great if you shared your icons!

However there are not many signals in US with tagged details beyond the main/distant category, so most of the icons probably won't get used (at least not in the near future.)

However I did find a particular tag that seems to be used somewhat frequently:

railway:signal:stop=US:GCOR:stop
railway:signal:stop:form=sign

See the usages on Overpass turbo.

If you have an idea how to visualize this kind of signal, it would be great to add it to this PR as well.

Thanks!

[RailandSea]

Clear Signals
Colour Position Light Signals used on the Amtrak NEC
Amtral Clear.tiff

Colour Light Signals (Interlocking and Automatic Wayside Signals)
Clear C2.tiff
Clear C1.tiff
C.tiff

Approach Clear Signal (used in TWC/Dark Territory approaching an interlocking)
APP Clear.tiff

Metro-North Railroad
Wayside Interlocking Proceed Signal. (Single Flashing Green)

Grand Central Terminal Proceed Signal

Long Island Railroad
Reduced Aspect Signal: Proceed (Interlocking Only)

[RailandSea]

CLEAR and STOP Signals used for GCOR

[The3dVehicleguy]

@RailandSea As nice as this would be the issue is there are no specific aspects on a majority of the US rail network to allow proper tagging and rendering right now. A issue of this is the lack or non-existent standard for railroad signaling and rules on a national level. The other issue is that there currently is no tagging schema available or standard that is adopted on OpenStreetMaps for tagging specific railroad signals, their aspects, signaling type, etc. I wish there was more and might be in the future but for right now the tagging schema needs to be developed further.

[RailandSea]

My question is how do make a tag for a signal let's say for MNRR only to display that specific signal vs a regular high clear signal icon used as a default tag for GCOR railroad?

[detective-fiasco]

Finalized differentiation of main normal or dwarf signals.

Dwarf signals have two icons based on railway:signal:position
Normal-height signal rendering remains unchanged.

http://localhost:8000/#view=16.54/41.220617/-96.02619&style=signals

This PR	Before

[detective-fiasco]

The failed API tests seem not to be connected to the changes in this PR. The feature test is passing.

At this point there is not much else to do, as there is no standardized tagging for other signals.
The only change is described here: #952 (comment)

This PR is now complete.

[hiddewie]

Thank you, nice!

Verified on http://localhost:8000/#view=16.46/41.300479/-72.922281&style=signals around New Haven: