Portland Trimet Portolan Data Catalog (Mirror)

This is a portolan catalog version of https://developer.trimet.org/gis/ - taking the static data layers there and making them fully cloud-native and interactive.

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rail-lines

Details

Visibility: Public
Owner: Chris Holmes
Created: 3 Aug 2026
Last Updated: 3 Aug 2026

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README

TriMet Rail Lines

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 covering the TriMet service district in the Portland, Oregon metropolitan area, published by TriMet as tm_rail_lines and last updated at the source on September 26, 2024.

TriMet's rail network — MAX light rail, WES commuter rail and Portland Streetcar — as 171 segments generalized for cartographic display. Each segment records which line or lines run over it (line), whether it is at surface level, on a bridge or in a tunnel (passage), its operational status, and its service type.

The line codes are what make this layer unusual: a value like BGR means the Blue, Green and Red lines all share that track. That is why TriMet draws it with a solid base stroke plus one dashed overlay per additional line, and why styles/default.json here does the same.

Agents: see AGENTS.md for join keys, verified query recipes and the caveats that will otherwise cost you a wrong answer.

🗺️ Open this collection in the data browser →

Preview it on a map, inspect the schema and license, and download the GeoParquet or PMTiles directly.

Quick start

Read it straight from object storage — DuckDB fetches only the byte ranges it needs, so there is nothing to download first:

Or with GeoPandas:

Suggested uses

Drawing the rail network at metro scale. This is what the layer is for — TriMet says so — and this collection ships a direct reproduction of TriMet's own GeoServer style for it.
Showing which services share trackage, which the line codes encode directly and no other layer in this catalog does.
Distinguishing at-grade from grade-separated running via passage.

Limitations and inappropriate uses

Generalized geometry. Do not measure it. TriMet states the data "have been generalized to improve cartographic display at smaller scales". Track lengths computed here will be short, and the alignment will not sit on the real right-of-way at large scale. Use routes for the operational alignment.
passage is a drawing hint, not an inventory. TriMet's own note: this attribute "is intended for use in cartographic display rather than analysis". It does not identify specific bridges or tunnels.
Not a track or signalling model. Segments are cartographic units. There is no notion of track count, direction of running, junctions or switches.

Schema

Column	Type	Description
`line`	string	Line(s) serving a particular segment. Values: `AL` Portland Streetcar A Loop; `AL/BL` Portland Streetcar A & B Loops; `AUX` Auxiliary track. No revenue service; `B` MAX Blue Line; `BG` MAX Blue, and Green Lines; `BGR` MAX Blue, Green, and Red Lines; `BGRY` MAX Blue, Green, Red, and Yellow Lines; `BL` Portland Streetcar B Loop; `BL/NS` Portland Streetcar B Loop and North/South Line; `BR` MAX Blue and Red Lines; `G` MAX Green Line; `GO` MAX Green and Orange Lines; `GY` MAX Green and Yellow Lines; `NS` Portland Streetcar North/South Line; `NS/AL` Portland Streetcar A Loop and North/South Line; `NS/AL/BL` Portland Streetcar A & B Loops and North/South Line; `O` MAX Orange Line; `O/AL/BL` MAX Orange Line and Portland Streetcar A & B Loops; `R` MAX Red Line; `WES` WES (Westside Express Service); `Y` MAX Yellow Line.
`passage`	string	Indicates the infrastructure (if any) over/through which a rail segment travels. This data is intended for use in cartographic display rather than analysis Values: `bridge` Rail segment travels over bridge; `surface` Rail segment travels over ground/surface level; Rail segment passes through tunnel.

Column descriptions are TriMet's own, taken verbatim from meta_tm_rail_lines.shtml. The same text is carried in table:columns in collection.json.

Visualization

Style	What it shows
`default.json`	A direct reproduction of TriMet's published GeoServer style `ott:rail`, whose rules key on exactly the LINE values this layer carries. Each segment gets a solid base stroke in its trunk line's color, then one dashed overlay per additional line sharing the track — so the four-line trunk through downtown Portland reads as blue under red, green and yellow dashes, the way it does on TriMet's own maps. Widths step at zoom 12, standing in for the SLD's scale break at denominator 151181. Dash lengths are converted from SLD pixels into MapLibre line-widths using the low-zoom width, so they match exactly below zoom 12 and run proportionally shorter above it. AUX segments carry no SLD rule and are drawn neutral gray rather than dropped.
`by-passage.json`	Encodes the PASSAGE attribute — whether a segment runs at surface level, over a bridge, or through a tunnel. Bridges are drawn heavy and dark, tunnels dashed, surface track light. TriMet notes that PASSAGE is intended for cartographic display rather than analysis, so read this as a drawing hint and not an infrastructure inventory.
`by-type.json`	Collapses the twenty LINE values into the four TYPE values: light rail, streetcar, commuter rail, and the shared MAX/streetcar segment. Colors come from TriMet's GTFS route_color. Simpler than the default style and easier to read at metro-wide zooms.
`labeled.json`

The PMTiles layer is named rail-lines. Styles reference it as ../rail-lines.pmtiles, so they load unmodified against this directory.

Files

File	Size	What it is
`rail-lines.parquet`	89.6 KB	GeoParquet 1.1, 171 rows in 1 row group(s), zstd, Hilbert-ordered, bbox covering column
`rail-lines.pmtiles`	60.8 KB	Vector tiles for display, every feature kept at every zoom
`thumbnail.webp`	47.7 KB	Rendered from `styles/default.json` over a light basemap
`collection.json`	—	STAC Collection metadata

Provenance

Produced by TriMet GIS (4012 SE 17th Ave, GIS3, Portland, OR 97202, gis@trimet.org) and distributed at developer.trimet.org/gis as tm_rail_lines.

The originals are linked as assets and are the authoritative copy: Shapefile · KML · Metadata

This collection was produced by converting TriMet's Shapefile to GeoParquet, keeping its native EPSG:2913 (NAD83(HARN) / Oregon North (ft)), and to PMTiles in WGS84 for display. No features were added, removed or edited. The exact commands are in tools/convert.py.

Contributing

This catalog is generated, and both halves are open source: the catalog at cholmes/portolan-catalog-trimet and the data browser at cholmes/trimet-data-browser. If something here is wrong or could be better — a description, a column definition, a query, a style — open an issue or send a pull request. Corrections to the underlying data go to TriMet at gis@trimet.org.

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.