diff --git a/src/data/transitFeeds.js b/src/data/transitFeeds.js
index 10d087747..5cbdac82d 100644
--- a/src/data/transitFeeds.js
+++ b/src/data/transitFeeds.js
@@ -304,6 +304,12 @@ export const TRANSIT_FEED_REGISTRY = Object.freeze([
       note: 'The City publishes this endpoint from the TTC BusTime NVAS catalogue entry, whose own licence field reads \"License not specified\"; the quote above is the portal-wide Open Government Licence \u2013 Toronto the City applies to its open data, so the credit carries the licence name the way the Metro Transit entry carries its public-domain note. BusTime is the surface system: buses and streetcars report real positions, the subway reports none, so Lines 1/2/4 are simply absent rather than inferred. The endpoint sends no ETag or Last-Modified, so conditional requests fall through to the proxy snapshot TTL.',
     }),
     defaultMode: 'bus',
+    // Toronto rides streetcars. The vehicles are the shared `tram` mode and
+    // share its silhouette and speed limits; only the word a reader sees
+    // changes, because "tram" is not what anyone at Queen and Spadina says.
+    modeWords: Object.freeze({
+      tram: Object.freeze({ word: 'Streetcar', abbr: 'STREETCAR' }),
+    }),
     routeMode: ttcRouteMode,
   }),
 ]);
diff --git a/src/layers/transit/policy.js b/src/layers/transit/policy.js
index b672581bb..33352bf2d 100644
--- a/src/layers/transit/policy.js
+++ b/src/layers/transit/policy.js
@@ -345,7 +345,7 @@ export function buildTransitSelectionCopy(
   // The mode is said in words on its own line. A glyph and a route id do not
   // tell a reader that the dot on Tremont Street is a subway train, and a
   // subway drawn on a street reads as a bug until the card says what it is.
-  const kindWord = TRANSIT_MODE_WORD[mode] || TRANSIT_MODE_WORD.unknown;
+  const kindWord = transitModeWord(mode, feed);
   const details = [`${kindWord} · ${feed.name} · ${feed.region}`];
   const motion = [];
   // What the SCREEN is doing leads, because that is what the reader can check.
@@ -479,6 +479,37 @@ export const TRANSIT_MODE_ABBR = Object.freeze({
   unknown: 'TRANSIT',
 });
 
+/**
+ * The mode in the operator's own vocabulary. A Toronto 501 and a Helsinki 1010
+ * are both the `tram` mode, but only one of them is called a tram by the people
+ * who ride it. A feed may name the modes it runs; everything else falls through
+ * to the shared table, so an override renames one word and nothing else.
+ * @param {string} mode Resolved transit mode.
+ * @param {object|null} [feed] Registry entry.
+ * @returns {string}
+ */
+export function transitModeWord(mode, feed = null) {
+  return (
+    feed?.modeWords?.[mode]?.word ||
+    TRANSIT_MODE_WORD[mode] ||
+    TRANSIT_MODE_WORD.unknown
+  );
+}
+
+/**
+ * The operator's short mode word for the fixed-width detection fields.
+ * @param {string} mode Resolved transit mode.
+ * @param {object|null} [feed] Registry entry.
+ * @returns {string}
+ */
+export function transitModeAbbr(mode, feed = null) {
+  return (
+    feed?.modeWords?.[mode]?.abbr ||
+    TRANSIT_MODE_ABBR[mode] ||
+    TRANSIT_MODE_ABBR.unknown
+  );
+}
+
 /**
  * The bright first line of a vehicle's detection label: its route when the feed
  * names one, else the fleet number, else the raw id. What a person standing at
@@ -521,7 +552,7 @@ export function elideRouteText(text) {
  * @returns {string}
  */
 export function transitDetectionClass(mode, feed) {
-  const kind = TRANSIT_MODE_ABBR[mode] || TRANSIT_MODE_ABBR.unknown;
+  const kind = transitModeAbbr(mode, feed);
   const operator =
     typeof feed?.name === 'string' ? feed.name.toUpperCase() : '';
   return operator ? `${kind} ${operator}`.slice(0, 20) : kind;
@@ -538,10 +569,17 @@ export function transitDetectionClass(mode, feed) {
  *
  * @param {object} record Normalized vehicle record.
  * @param {string} mode Resolved transit mode.
+ * @param {number} [nowMs]
+ * @param {object|null} [feed] Registry entry, for its own mode vocabulary.
  * @returns {string}
  */
-export function transitDetectionMetric(entry, mode, nowMs = Date.now()) {
-  const kind = TRANSIT_MODE_ABBR[mode] || TRANSIT_MODE_ABBR.unknown;
+export function transitDetectionMetric(
+  entry,
+  mode,
+  nowMs = Date.now(),
+  feed = null,
+) {
+  const kind = transitModeAbbr(mode, feed);
   const state = transitVehicleState(entry, nowMs);
   return state ? `${kind} ${state}` : kind;
 }
diff --git a/src/layers/transit/queries.js b/src/layers/transit/queries.js
index 68367dc70..470006c85 100644
--- a/src/layers/transit/queries.js
+++ b/src/layers/transit/queries.js
@@ -12,6 +12,20 @@ import {
 } from '../../data/transitFeeds.js';
 import { transitModeTier } from '../../data/transitPresetStyle.js';
 
+/**
+ * The registry entry behind a vehicle. Live feeds answer first so a feed the
+ * session disabled stops supplying vocabulary; the registry is the fallback,
+ * because a vehicle can outlive the poll that brought it.
+ * @param {object} state Layer state.
+ * @param {object} entry Vehicle entry.
+ * @returns {object|null}
+ */
+function feedForEntry(state, entry) {
+  const id = entry?.feedId;
+  if (!id) return null;
+  return state._activeFeeds.get(id) || getRegisteredTransitFeed(id) || null;
+}
+
 /**
  * The layer row's answer to "what is on screen and is it honest?".
  * @param {object} context
@@ -101,6 +115,7 @@ export function createQueries({ state, parts }) {
           contact._entry,
           contact._entry.mode,
           now,
+          feedForEntry(state, contact._entry),
         );
       return;
     }
@@ -132,10 +147,10 @@ export function createQueries({ state, parts }) {
         entry.labelRecord = entry.record;
       }
       if (!entry.labelClass || entry.labelMode !== entry.mode) {
-        const feed =
-          state._activeFeeds.get(entry.feedId) ||
-          getRegisteredTransitFeed(entry.feedId);
-        entry.labelClass = transitDetectionClass(entry.mode, feed);
+        entry.labelClass = transitDetectionClass(
+          entry.mode,
+          feedForEntry(state, entry),
+        );
         entry.labelMode = entry.mode;
       }
       const contact = {
@@ -146,7 +161,12 @@ export function createQueries({ state, parts }) {
         id: entry.labelId,
         type: 'VEH',
         klass: entry.labelClass,
-        metric: transitDetectionMetric(entry, entry.mode, now),
+        metric: transitDetectionMetric(
+          entry,
+          entry.mode,
+          now,
+          feedForEntry(state, entry),
+        ),
         // The bracket carries the mode colour in every preset: the detection
         // canvas sits above the post-FX chain, where the sprites' own colour
         // is lost under NVG and FLIR. Keyless too — the feeds are keyless.
diff --git a/src/layers/transit/vocabulary.test.mjs b/src/layers/transit/vocabulary.test.mjs
new file mode 100644
index 000000000..17441e770
--- /dev/null
+++ b/src/layers/transit/vocabulary.test.mjs
@@ -0,0 +1,52 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  buildTransitSelectionCopy,
+  transitDetectionClass,
+  transitDetectionMetric,
+  transitModeAbbr,
+  transitModeWord,
+} from './policy.js';
+import { getTransitFeed } from '../../data/transitFeeds.js';
+
+const ttc = () => getTransitFeed('ttc-toronto');
+const hsl = () => getTransitFeed('hsl-helsinki');
+
+test('an operator that names its own vehicles overrides the shared mode word', () => {
+  // A Toronto 501 is a streetcar. A Helsinki 1010 is a tram. Both are the
+  // `tram` mode, so the word a reader sees has to come from the operator,
+  // not from the mode.
+  assert.equal(transitModeWord('tram', ttc()), 'Streetcar');
+  assert.equal(transitModeAbbr('tram', ttc()), 'STREETCAR');
+  assert.equal(transitModeWord('tram', hsl()), 'Tram');
+  assert.equal(transitModeAbbr('tram', hsl()), 'TRAM');
+});
+
+test('an override renames one mode, never the rest of the feed', () => {
+  assert.equal(transitModeWord('bus', ttc()), 'Bus');
+  assert.equal(transitModeWord('subway', ttc()), 'Subway');
+  assert.equal(transitModeAbbr('bus', ttc()), 'BUS');
+});
+
+test('a missing feed or unknown mode falls back to the shared table', () => {
+  assert.equal(transitModeWord('tram', null), 'Tram');
+  assert.equal(transitModeWord('spaceship', ttc()), 'Transit vehicle');
+  assert.equal(transitModeAbbr('spaceship', ttc()), 'TRANSIT');
+  assert.equal(transitModeWord('tram', { name: 'No override' }), 'Tram');
+});
+
+test('the selection card calls a Toronto 501 a streetcar', () => {
+  const record = { id: '4400', routeId: '501', timestamp: 0 };
+  const copy = buildTransitSelectionCopy(ttc(), record, 'tram', 0, null, null);
+  assert.match(copy.details.join(' | '), /Streetcar · TTC/);
+  assert.doesNotMatch(copy.details.join(' | '), /Tram/);
+});
+
+test('detection labels carry the operator vocabulary within the field width', () => {
+  const klass = transitDetectionClass('tram', ttc());
+  assert.equal(klass, 'STREETCAR TTC');
+  assert.ok(klass.length <= 20, 'fits the detection class field');
+  assert.equal(transitDetectionClass('tram', hsl()), 'TRAM HSL');
+  const metric = transitDetectionMetric({ mode: 'tram' }, 'tram', 0, ttc());
+  assert.match(metric, /^STREETCAR/);
+});