TriMet Rail Lines — agent guide

Public transit rail lines. Includes existing, under construction, and planned MAX, WES, and Portland Streetcar lines. The data have been generalized to improve cartographic display at smaller scales. 171 LineString features, WGS84, one GeoParquet file of 89.6 KB in 1 row group(s).

Access

Reads stream over HTTP range requests — query in place, do not download. The file is Hilbert-ordered and carries a GeoParquet 1.1 bbox covering column, so a spatial filter on geometry_bbox prunes row groups from metadata alone. Note the column name: GDAL writes the covering as <geometry column>_bbox, so it is geometry_bbox here, not bbox.

The recipes below use bare relative paths ('rail-lines/rail-lines.parquet') for readability. Prefix them with https://data.source.coop/cholmes/trimet/ to run remotely.

Other formats: rail-lines.pmtiles for map display (layer name rail-lines), and TriMet's original Shapefile and KML, linked from collection.json as source_shapefile and source_kml.

Coordinate system, and what follows from it

The GeoParquet is in EPSG:2913 — NAD83(HARN) / Oregon North, international feet — which is what TriMet surveys and publishes in. It is deliberately not reprojected. Only the PMTiles are in WGS84, because vector tiles are Web Mercator by definition.

The practical consequence is a good one: measurements just work, in feet.

Useful conversions: × 0.3048 for metres, ÷ 5280 for miles, ÷ 43560 for acres, ÷ 27878400 for square miles. 400 m is 1312.34 ft, a quarter mile is 1320 ft.

Two things to watch:

• Coordinates are not longitude and latitude. An x of 7633099 is feet east of the projection's false origin, not a degree. Anything expecting lon/lat — a web map, a geocoder, most GeoJSON consumers — needs a transform first.
• always_xy := true when you do transform. Without it DuckDB honours EPSG:4326's authority-declared latitude-first axis order and every result comes back Infinity:

The bbox covering column is in the same feet, so a spatial filter written against it uses projected coordinates, not degrees. The collection's STAC extent stays in WGS84, because STAC requires that regardless of the data's own CRS.

Nothing here carries a pre-computed length or area except the district boundary, which has TriMet's own area_sq_mi and acres.

Quirks and caveats

The metadata documents BL/NS; the data contains NS/BL

TriMet's metadata page lists a code BL/NS ("Portland Streetcar B Loop and North/South Line"). That string does not occur in the data. What the data actually carries is NS/BL, on 2 segments here and 12 stops in rail-stops. Filter on NS/BL. A query written from the published code list alone returns nothing.

AUX is in the data and in TriMet's code list, but has no style rule

7 segments are AUX — "Auxiliary track. No revenue service", i.e. yard leads and connecting track. TriMet's own SLD has no rule for AUX, so on TriMet's maps these segments are invisible. This catalog draws them in neutral gray rather than dropping them, so be aware they will appear where TriMet's maps show nothing. Exclude AUX when counting revenue track.

Everything is Existing right now

status documents Existing, Planned and UC (under construction), but all 171 current segments are Existing. Code that branches on status is not wrong, it is just untested against this snapshot — and the values will reappear as TriMet adds projects.

line is a set, encoded as a string

There is no join table. To ask "which segments does the Blue Line touch", you must match any code containing B as a component, which is not a substring test — B appears in BL (B Loop, a streetcar) and BGR. The reliable approach is an explicit list of the codes that include the line you want; see the recipes.

Colors here differ slightly from the GTFS colors

TriMet's SLD uses #084C8D for the Blue Line; its GTFS route_color is #1359AE. Both are authentic TriMet values from different systems. This collection's default.json follows the SLD, because the SLD is the style written for this layer; by-type.json follows GTFS.

Query recipes

Segments carrying the MAX Blue Line, handling shared track correctly

How much track is shared, and by how many lines

Grade separation by mode, excluding non-revenue track

Related collections

• rail-stops — the stations on these lines, sharing the same line codes and colors
• routes — the operational, non-generalized alignment of the same rail service

Provenance

TriMet publishes this as tm_rail_lines at developer.trimet.org/gis, last updated September 26, 2024. Every column description in collection.json comes from TriMet's metadata page — that page, not this catalog, is the authority on what a field means.

Conversion: ogr2ogr -f Parquet -t_srs EPSG:4326 -lco COMPRESSION=ZSTD -lco SORT_BY_BBOX=YES -lco WRITE_COVERING_BBOX=YES, then tippecanoe with -r1 --no-feature-limit so no feature is dropped at any zoom. See tools/convert.py.

License, and a warning

TriMet distributes these datasets free of charge, but the terms of use do not grant redistribution rights. Section 4 of TriMet's Terms of Use reserves reproduction, modification, distribution and republication of site Content without written consent; the redistribution license in section 5 covers the Web Services API, not these GIS downloads. The collections therefore declare "license": "other" with a link to those terms, rather than claiming an open license the source does not offer.

Practically: use the data, and contact gis@trimet.org before redistributing it or building a product on it. If you need transit data under clear open terms, TriMet's GTFS feed is the better starting point.