Add multi-route comparison with Yen's k-shortest-paths algorithm

- Yen's algorithm in Rust: finds up to 3 distinct shortest routes by
  iteratively deviating from previously found paths with node exclusions
- Routes are deduplicated by station sequence (same stations = same route
  even if timing differs slightly)
- Dijkstra refactored to support node exclusion sets for Yen's spur paths
- WASM API returns JSON array of RouteResult (was single object)
- Frontend routing store holds multiple routes with selectedRouteIndex
- Route tabs: "Fastest", "Alternative 1", "Alternative 2" with distinct
  colors (orange, blue, purple), click to switch and resample trajectory
- Compact route planner layout: 2-column From/To, shorter window buttons
- Tested: Earth L1 → Jupiter L1 finds 2-leg relay via Mercury L1 (6.9mo)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/mass-driver-core/src/router.rs

@@ -1,145 +1,118 @@
 use crate::route::{RouteLeg, RouteResult};
 use crate::transfer_matrix::TransferMatrix;
 use std::cmp::Reverse;
-use std::collections::BinaryHeap;
+use std::collections::{BinaryHeap, HashSet};
 
-/// Find the optimal route between two stations using Dijkstra on
-/// the time-expanded graph.
-///
-/// Nodes: (station_id, week_index)
-/// Transfer edges: based on precomputed transfer matrix
-/// Wait edges: (station, t) → (station, t+1) with cost 1 week
-///
-/// # Arguments
-/// * `matrix` - Precomputed transfer matrix
-/// * `from` - Source station index
-/// * `to` - Destination station index
-/// * `earliest_week` - Earliest allowed departure week
-/// * `latest_week` - Latest allowed departure week
-///
-/// # Returns
-/// The optimal route, or None if no route exists.
-pub fn find_optimal_route(
+/// Build the transfer lookup table for fast Dijkstra edge iteration.
+fn build_transfer_lookup(matrix: &TransferMatrix) -> Vec<Vec<(u16, u16)>> {
+    let n = matrix.station_count;
+    let t_max = matrix.week_count;
+    let mut lookup: Vec<Vec<(u16, u16)>> = vec![Vec::new(); n * t_max];
+    for entry in &matrix.entries {
+        let key = entry.from as usize * t_max + entry.departure_week as usize;
+        if key < lookup.len() {
+            lookup[key].push((entry.to, entry.travel_weeks));
+        }
+    }
+    lookup
+}
+
+/// Run Dijkstra with optional node exclusions.
+/// Returns (path_as_node_ids, total_cost) or None.
+fn dijkstra_with_exclusions(
     matrix: &TransferMatrix,
+    transfer_lookup: &[Vec<(u16, u16)>],
     from: usize,
     to: usize,
     earliest_week: usize,
     latest_week: usize,
-) -> Option<RouteResult> {
+    excluded_nodes: &HashSet<usize>,
+) -> Option<(Vec<usize>, u32)> {
     let n = matrix.station_count;
     let t_max = matrix.week_count;
-
-    if from >= n || to >= n || from == to {
-        return None;
-    }
-
-    let latest_week = latest_week.min(t_max - 1);
-    if earliest_week > latest_week {
-        return None;
-    }
-
-    // Node encoding: node_id = station * t_max + week
     let node_count = n * t_max;
+
     let mut dist = vec![u32::MAX; node_count];
     let mut prev: Vec<Option<usize>> = vec![None; node_count];
-
-    // Min-heap: (cost, node_id)
     let mut heap: BinaryHeap<Reverse<(u32, usize)>> = BinaryHeap::new();
 
-    // Seed: all departure times from the source station
     for week in earliest_week..=latest_week {
         let node = from * t_max + week;
-        let cost = (week - earliest_week) as u32; // Waiting at origin costs time
+        if excluded_nodes.contains(&node) {
+            continue;
+        }
+        let cost = (week - earliest_week) as u32;
         dist[node] = cost;
         heap.push(Reverse((cost, node)));
     }
 
-    // Build a lookup for transfer matrix entries by (from, departure_week)
-    // for faster access during Dijkstra
-    let mut transfer_lookup: Vec<Vec<(u16, u16)>> = vec![Vec::new(); n * t_max];
-    for entry in &matrix.entries {
-        let key = entry.from as usize * t_max + entry.departure_week as usize;
-        if key < transfer_lookup.len() {
-            transfer_lookup[key].push((entry.to, entry.travel_weeks));
-        }
-    }
-
     while let Some(Reverse((cost, u))) = heap.pop() {
         let u_station = u / t_max;
         let u_week = u % t_max;
 
-        // Found destination — reconstruct path
         if u_station == to {
-            return Some(reconstruct_route(matrix, &prev, u, earliest_week, t_max));
+            // Reconstruct path
+            let mut path = Vec::new();
+            let mut node = u;
+            loop {
+                path.push(node);
+                match prev[node] {
+                    Some(p) => node = p,
+                    None => break,
+                }
+            }
+            path.reverse();
+            return Some((path, cost));
         }
 
-        // Skip stale entries
         if cost > dist[u] {
             continue;
         }
 
-        // Wait edge: stay at this station for one more week
+        // Wait edge
         if u_week + 1 < t_max {
-            let v = u + 1; // Same station, next week
-            let new_cost = cost + 1;
-            if new_cost < dist[v] {
-                dist[v] = new_cost;
-                prev[v] = Some(u);
-                heap.push(Reverse((new_cost, v)));
+            let v = u + 1;
+            if !excluded_nodes.contains(&v) {
+                let new_cost = cost + 1;
+                if new_cost < dist[v] {
+                    dist[v] = new_cost;
+                    prev[v] = Some(u);
+                    heap.push(Reverse((new_cost, v)));
+                }
             }
         }
 
-        // Transfer edges from this station at this week
+        // Transfer edges
         let key = u_station * t_max + u_week;
         if key < transfer_lookup.len() {
             for &(to_station, travel_weeks) in &transfer_lookup[key] {
                 let arrival_week = u_week + travel_weeks as usize;
                 if arrival_week < t_max {
                     let v = to_station as usize * t_max + arrival_week;
-                    let new_cost = cost + travel_weeks as u32;
-                    if new_cost < dist[v] {
-                        dist[v] = new_cost;
-                        prev[v] = Some(u);
-                        heap.push(Reverse((new_cost, v)));
+                    if !excluded_nodes.contains(&v) {
+                        let new_cost = cost + travel_weeks as u32;
+                        if new_cost < dist[v] {
+                            dist[v] = new_cost;
+                            prev[v] = Some(u);
+                            heap.push(Reverse((new_cost, v)));
+                        }
                     }
                 }
             }
         }
     }
 
-    None // No route found
+    None
 }
 
-fn reconstruct_route(
-    _matrix: &TransferMatrix,
-    prev: &[Option<usize>],
-    end_node: usize,
-    earliest_week: usize,
-    t_max: usize,
-) -> RouteResult {
-    let mut path = Vec::new();
-    let mut node = end_node;
-
-    // Trace back through prev pointers
-    loop {
-        path.push(node);
-        match prev[node] {
-            Some(p) => node = p,
-            None => break,
-        }
-    }
-
-    path.reverse();
-
-    // Convert path to route legs
+/// Convert a raw node path into a RouteResult.
+fn path_to_route(path: &[usize], t_max: usize) -> RouteResult {
     let mut legs = Vec::new();
     let mut i = 0;
 
     while i < path.len() {
         let station = path[i] / t_max;
-        let _week = path[i] % t_max;
 
-        // Find next different station in path
         let mut j = i + 1;
         while j < path.len() && path[j] / t_max == station {
             j += 1;
@@ -147,7 +120,7 @@ fn reconstruct_route(
 
         if j < path.len() {
             let next_station = path[j] / t_max;
-            let departure_week = path[j - 1] % t_max; // Last week at current station
+            let departure_week = path[j - 1] % t_max;
             let arrival_week = path[j] % t_max;
             let wait_weeks = if i == 0 {
                 departure_week - (path[0] % t_max)
@@ -167,12 +140,7 @@ fn reconstruct_route(
         i = j;
     }
 
-    let departure_week = if !path.is_empty() {
-        path[0] % t_max
-    } else {
-        earliest_week
-    };
-
+    let departure_week = if !path.is_empty() { path[0] % t_max } else { 0 };
     let total_time = if !path.is_empty() {
         (path.last().unwrap() % t_max) - departure_week
     } else {
@@ -185,3 +153,177 @@ fn reconstruct_route(
         departure_week: departure_week as u32,
     }
 }
+
+/// Find the single optimal route.
+pub fn find_optimal_route(
+    matrix: &TransferMatrix,
+    from: usize,
+    to: usize,
+    earliest_week: usize,
+    latest_week: usize,
+) -> Option<RouteResult> {
+    let n = matrix.station_count;
+    let t_max = matrix.week_count;
+    if from >= n || to >= n || from == to { return None; }
+    let latest_week = latest_week.min(t_max - 1);
+    if earliest_week > latest_week { return None; }
+
+    let lookup = build_transfer_lookup(matrix);
+    let empty = HashSet::new();
+
+    let (path, _cost) = dijkstra_with_exclusions(
+        matrix, &lookup, from, to, earliest_week, latest_week, &empty,
+    )?;
+
+    Some(path_to_route(&path, t_max))
+}
+
+/// Find k-shortest paths using Yen's algorithm.
+///
+/// Returns up to `k` routes sorted by total time (shortest first).
+/// Routes are guaranteed to be distinct (different station sequences).
+pub fn find_k_shortest_routes(
+    matrix: &TransferMatrix,
+    from: usize,
+    to: usize,
+    earliest_week: usize,
+    latest_week: usize,
+    k: usize,
+) -> Vec<RouteResult> {
+    let n = matrix.station_count;
+    let t_max = matrix.week_count;
+    if from >= n || to >= n || from == to || k == 0 { return vec![]; }
+    let latest_week = latest_week.min(t_max - 1);
+    if earliest_week > latest_week { return vec![]; }
+
+    let lookup = build_transfer_lookup(matrix);
+    let empty = HashSet::new();
+
+    // Step 1: Find the shortest path
+    let (first_path, first_cost) = match dijkstra_with_exclusions(
+        matrix, &lookup, from, to, earliest_week, latest_week, &empty,
+    ) {
+        Some(r) => r,
+        None => return vec![],
+    };
+
+    let mut a_paths: Vec<(Vec<usize>, u32)> = vec![(first_path, first_cost)];
+    let mut b_candidates: Vec<(Vec<usize>, u32)> = Vec::new();
+
+    // Track which station sequences we've already found to ensure diversity
+    let mut seen_sequences: HashSet<Vec<usize>> = HashSet::new();
+    seen_sequences.insert(
+        station_sequence(&a_paths[0].0, t_max),
+    );
+
+    for ki in 1..k {
+        let prev_path = &a_paths[ki - 1].0;
+
+        // For each spur node in the previous path, find a deviation
+        // We operate on "station transition" points in the path
+        let transition_indices = find_transition_indices(prev_path, t_max);
+
+        for &spur_idx in &transition_indices {
+            let spur_node = prev_path[spur_idx];
+
+            // Exclude nodes used by the root path (before spur point)
+            // and nodes from previously found paths that share the same root
+            let mut excluded = HashSet::new();
+
+            // Exclude the internal nodes of the root path up to spur
+            for &node in &prev_path[..spur_idx] {
+                excluded.insert(node);
+            }
+
+            // Exclude edges/nodes from all existing A-paths that share
+            // the same root (same path up to spur_idx)
+            for (existing_path, _) in &a_paths {
+                if existing_path.len() > spur_idx
+                    && existing_path[..=spur_idx] == prev_path[..=spur_idx]
+                {
+                    // Exclude the next node after spur in this existing path
+                    if spur_idx + 1 < existing_path.len() {
+                        excluded.insert(existing_path[spur_idx + 1]);
+                    }
+                }
+            }
+
+            // Find shortest path from spur to destination
+            let spur_station = spur_node / t_max;
+            let spur_week = spur_node % t_max;
+
+            if let Some((spur_path, spur_cost)) = dijkstra_with_exclusions(
+                matrix, &lookup, spur_station, to,
+                spur_week, latest_week, &excluded,
+            ) {
+                // Combine root + spur path
+                let mut full_path = prev_path[..spur_idx].to_vec();
+                full_path.extend_from_slice(&spur_path);
+
+                let root_cost = if spur_idx > 0 {
+                    // Cost of root portion
+                    (prev_path[spur_idx] % t_max - prev_path[0] % t_max) as u32
+                } else {
+                    0
+                };
+                let total_cost = root_cost + spur_cost;
+
+                let seq = station_sequence(&full_path, t_max);
+                if !seen_sequences.contains(&seq) {
+                    b_candidates.push((full_path, total_cost));
+                }
+            }
+        }
+
+        if b_candidates.is_empty() {
+            break;
+        }
+
+        // Pick the best candidate
+        b_candidates.sort_by_key(|(_, cost)| *cost);
+
+        // Find the first candidate with a unique station sequence
+        let mut found = false;
+        while !b_candidates.is_empty() {
+            let (path, cost) = b_candidates.remove(0);
+            let seq = station_sequence(&path, t_max);
+            if !seen_sequences.contains(&seq) {
+                seen_sequences.insert(seq);
+                a_paths.push((path, cost));
+                found = true;
+                break;
+            }
+        }
+
+        if !found {
+            break;
+        }
+    }
+
+    a_paths.into_iter().map(|(path, _)| path_to_route(&path, t_max)).collect()
+}
+
+/// Extract the station-level sequence from a node path (ignoring time).
+fn station_sequence(path: &[usize], t_max: usize) -> Vec<usize> {
+    let mut seq = Vec::new();
+    let mut last_station = usize::MAX;
+    for &node in path {
+        let station = node / t_max;
+        if station != last_station {
+            seq.push(station);
+            last_station = station;
+        }
+    }
+    seq
+}
+
+/// Find indices in the path where the station changes (transition points).
+fn find_transition_indices(path: &[usize], t_max: usize) -> Vec<usize> {
+    let mut indices = vec![0]; // Always include the start
+    for i in 1..path.len() {
+        if path[i] / t_max != path[i - 1] / t_max {
+            indices.push(i);
+        }
+    }
+    indices
+}

crates/mass-driver-wasm/src/api.rs

@@ -213,17 +213,19 @@ pub fn compute_route(
         },
     );
 
-    // Find optimal route
-    let route = router::find_optimal_route(
+    // Find up to 3 shortest routes using Yen's algorithm
+    let routes = router::find_k_shortest_routes(
         &matrix,
         from_station,
         to_station,
         0,
         week_window.saturating_sub(1),
+        3,
     );
 
-    match route {
-        Some(r) => serde_json::to_string(&r).unwrap_or_default(),
-        None => String::new(),
+    if routes.is_empty() {
+        String::new()
+    } else {
+        serde_json::to_string(&routes).unwrap_or_default()
     }
 }

frontend/src/lib/stores/routing.svelte.ts

@@ -3,7 +3,10 @@ import type { RouteResult } from '$lib/wasm/bridge';
 class RoutingState {
 	fromStation = $state<number | null>(null);
 	toStation = $state<number | null>(null);
-	route = $state<RouteResult | null>(null);
+
+	// Multiple route alternatives
+	routes = $state<RouteResult[]>([]);
+	selectedRouteIndex = $state(0);
 	isComputing = $state(false);
 	error = $state('');
 	weekWindow = $state(260); // ~5 years search window
@@ -12,6 +15,24 @@ class RoutingState {
 	trajectoryPoints = $state<Float64Array>(new Float64Array(0));
 	routeProgress = $state(0); // 0..1 along the full route
 	isAnimating = $state(false);
+
+	// Derived: currently selected route
+	get route(): RouteResult | null {
+		return this.routes[this.selectedRouteIndex] ?? null;
+	}
+
+	get routeCount(): number {
+		return this.routes.length;
+	}
+
+	selectRoute(index: number) {
+		if (index >= 0 && index < this.routes.length) {
+			this.selectedRouteIndex = index;
+			// Reset animation when switching routes
+			this.routeProgress = 0;
+			// Trajectory will be resampled in the next frame by the renderer
+		}
+	}
 }
 
 export const routing = new RoutingState();

frontend/src/lib/wasm/bridge.ts

@@ -81,21 +81,23 @@ export function sampleRouteTrajectory(
 	return wasm.sample_route_trajectory(stationsJson, routeJson, jd, samplesPerLeg);
 }
 
-export function computeRoute(
+export function computeRoutes(
 	stationsJson: string,
 	fromStation: number,
 	toStation: number,
 	launchVelocityKms: number,
 	startJd: number,
 	weekWindow: number,
-): RouteResult | null {
+): RouteResult[] {
 	const wasm = getWasm();
-	if (!wasm) return null;
+	if (!wasm) return [];
 	const json = wasm.compute_route(stationsJson, fromStation, toStation, launchVelocityKms, startJd, weekWindow);
-	if (!json) return null;
+	if (!json) return [];
 	try {
-		return JSON.parse(json);
+		const result = JSON.parse(json);
+		// API now returns array of routes
+		return Array.isArray(result) ? result : [result];
 	} catch {
-		return null;
+		return [];
 	}
 }

frontend/src/routes/(simulator)/components/RoutingPanel.svelte

@@ -2,9 +2,12 @@
 	import { simulation } from '$lib/stores/simulation.svelte';
 	import { stations } from '$lib/stores/stations.svelte';
 	import { routing } from '$lib/stores/routing.svelte';
-	import { computeRoute, sampleRouteTrajectory } from '$lib/wasm/bridge';
+	import { computeRoutes, sampleRouteTrajectory } from '$lib/wasm/bridge';
 	import { formatWeeks } from '$lib/utils/format';
 
+	const ROUTE_COLORS = ['#ff6a33', '#4a9eff', '#cc44ff'];
+	const ROUTE_LABELS = ['Fastest', 'Alternative 1', 'Alternative 2'];
+
 	function handleCompute() {
 		if (routing.fromStation === null || routing.toStation === null) {
 			routing.error = 'Select both start and end stations';
@@ -17,13 +20,14 @@
 
 		routing.isComputing = true;
 		routing.error = '';
-		routing.route = null;
+		routing.routes = [];
+		routing.selectedRouteIndex = 0;
 		routing.trajectoryPoints = new Float64Array(0);
 		routing.routeProgress = 0;
 		routing.isAnimating = false;
 
 		setTimeout(() => {
-			const result = computeRoute(
+			const results = computeRoutes(
 				stations.stationsJson,
 				routing.fromStation!,
 				routing.toStation!,
@@ -32,11 +36,12 @@
 				routing.weekWindow,
 			);
 
-			if (result && result.legs.length > 0) {
-				routing.route = result;
+			if (results.length > 0) {
+				routing.routes = results;
+				routing.selectedRouteIndex = 0;
 
-				// Sample trajectory for visualization
-				const routeJson = JSON.stringify(result);
+				// Sample trajectory for the first (fastest) route
+				const routeJson = JSON.stringify(results[0]);
 				routing.trajectoryPoints = sampleRouteTrajectory(
 					stations.stationsJson, routeJson, simulation.currentJD, 60,
 				);
@@ -48,11 +53,23 @@
 		}, 50);
 	}
 
+	function selectRoute(index: number) {
+		routing.selectRoute(index);
+		// Resample trajectory for the newly selected route
+		const route = routing.routes[index];
+		if (route) {
+			const routeJson = JSON.stringify(route);
+			routing.trajectoryPoints = sampleRouteTrajectory(
+				stations.stationsJson, routeJson, simulation.currentJD, 60,
+			);
+		}
+	}
+
 	const windowOptions = [
-		{ label: '1 year', value: 52 },
-		{ label: '2 years', value: 104 },
-		{ label: '5 years', value: 260 },
-		{ label: '10 years', value: 520 },
+		{ label: '1 yr', value: 52 },
+		{ label: '2 yr', value: 104 },
+		{ label: '5 yr', value: 260 },
+		{ label: '10 yr', value: 520 },
 	];
 </script>
 
@@ -61,132 +78,149 @@
 		Route Planner
 	</h3>
 
-	<!-- From station -->
-	<div>
-		<label class="text-[10px] text-[var(--text-secondary)] mb-0.5 block">From</label>
-		<select
-			bind:value={routing.fromStation}
-			class="w-full bg-[var(--bg-primary)] text-xs text-[var(--text-primary)] border border-white/10 rounded px-2 py-1.5 [color-scheme:dark]"
-		>
-			<option value={null}>Select station...</option>
-			{#each stations.stationNames as name, i}
-				<option value={i}>{name}</option>
-			{/each}
-		</select>
-	</div>
-
-	<!-- To station -->
-	<div>
-		<label class="text-[10px] text-[var(--text-secondary)] mb-0.5 block">To</label>
-		<select
-			bind:value={routing.toStation}
-			class="w-full bg-[var(--bg-primary)] text-xs text-[var(--text-primary)] border border-white/10 rounded px-2 py-1.5 [color-scheme:dark]"
-		>
-			<option value={null}>Select station...</option>
-			{#each stations.stationNames as name, i}
-				<option value={i}>{name}</option>
-			{/each}
-		</select>
-	</div>
-
-	<!-- Search window -->
-	<div>
-		<label class="text-[10px] text-[var(--text-secondary)] mb-0.5 block">Search Window</label>
-		<div class="flex gap-1">
-			{#each windowOptions as opt}
-				<button
-					onclick={() => { routing.weekWindow = opt.value; }}
-					class="flex-1 px-1 py-0.5 text-[10px] rounded transition-colors {routing.weekWindow === opt.value
-						? 'bg-[var(--accent-blue)] text-white'
-						: 'bg-white/5 text-[var(--text-secondary)] hover:bg-white/10'}"
-				>
-					{opt.label}
-				</button>
-			{/each}
+	<!-- From / To -->
+	<div class="grid grid-cols-2 gap-2">
+		<div>
+			<label class="text-[10px] text-[var(--text-secondary)] mb-0.5 block">From</label>
+			<select
+				bind:value={routing.fromStation}
+				class="w-full bg-[var(--bg-primary)] text-[10px] text-[var(--text-primary)] border border-white/10 rounded px-1.5 py-1 [color-scheme:dark]"
+			>
+				<option value={null}>Station...</option>
+				{#each stations.stationNames as name, i}
+					<option value={i}>{name}</option>
+				{/each}
+			</select>
+		</div>
+		<div>
+			<label class="text-[10px] text-[var(--text-secondary)] mb-0.5 block">To</label>
+			<select
+				bind:value={routing.toStation}
+				class="w-full bg-[var(--bg-primary)] text-[10px] text-[var(--text-primary)] border border-white/10 rounded px-1.5 py-1 [color-scheme:dark]"
+			>
+				<option value={null}>Station...</option>
+				{#each stations.stationNames as name, i}
+					<option value={i}>{name}</option>
+				{/each}
+			</select>
 		</div>
 	</div>
 
-	<!-- Compute button -->
+	<!-- Search window + Compute -->
+	<div class="flex gap-1 items-center">
+		{#each windowOptions as opt}
+			<button
+				onclick={() => { routing.weekWindow = opt.value; }}
+				class="flex-1 px-1 py-0.5 text-[9px] rounded transition-colors {routing.weekWindow === opt.value
+					? 'bg-[var(--accent-blue)] text-white'
+					: 'bg-white/5 text-[var(--text-secondary)] hover:bg-white/10'}"
+			>
+				{opt.label}
+			</button>
+		{/each}
+	</div>
+
 	<button
 		onclick={handleCompute}
 		disabled={routing.isComputing || routing.fromStation === null || routing.toStation === null}
-		class="w-full py-2 px-3 text-xs font-semibold rounded transition-colors
+		class="w-full py-1.5 px-3 text-xs font-semibold rounded transition-colors
 			{routing.isComputing
 				? 'bg-[var(--accent-blue)]/50 text-white/50 cursor-wait'
 				: 'bg-[var(--accent-orange)] text-white hover:bg-[var(--accent-orange)]/80 disabled:opacity-30 disabled:cursor-not-allowed'}"
 	>
-		{#if routing.isComputing}
-			Computing route...
-		{:else}
-			Find Optimal Route
-		{/if}
+		{routing.isComputing ? 'Computing...' : 'Find Routes'}
 	</button>
 
-	<!-- Error -->
 	{#if routing.error}
 		<p class="text-[10px] text-red-400">{routing.error}</p>
 	{/if}
 
-	<!-- Route result -->
-	{#if routing.route}
+	<!-- Route alternatives -->
+	{#if routing.routes.length > 0}
 		<div class="border-t border-white/5 pt-2 mt-1">
-			<div class="flex justify-between items-baseline mb-2">
-				<span class="text-xs font-semibold text-[var(--accent-green)]">Route Found</span>
-				<span class="text-sm font-bold text-[var(--text-primary)]">
-					{formatWeeks(routing.route.total_time_weeks)}
-				</span>
-			</div>
+			<!-- Route tabs -->
+			{#if routing.routes.length > 1}
+				<div class="flex gap-1 mb-2">
+					{#each routing.routes as route, i}
+						<button
+							onclick={() => selectRoute(i)}
+							class="flex-1 px-1.5 py-1 text-[10px] rounded border transition-colors
+								{routing.selectedRouteIndex === i
+									? 'border-current text-white'
+									: 'border-white/10 text-[var(--text-secondary)] hover:border-white/20'}"
+							style={routing.selectedRouteIndex === i ? `color: ${ROUTE_COLORS[i]}; border-color: ${ROUTE_COLORS[i]}` : ''}
+						>
+							<div class="font-semibold">{ROUTE_LABELS[i]}</div>
+							<div class="text-[9px] opacity-70">{formatWeeks(route.total_time_weeks)}</div>
+						</button>
+					{/each}
+				</div>
+			{/if}
 
-			<div class="text-[10px] text-[var(--text-secondary)] mb-1">
-				Departs week {routing.route.departure_week} &middot; {routing.route.legs.length} leg{routing.route.legs.length !== 1 ? 's' : ''}
-			</div>
+			<!-- Selected route details -->
+			{#if routing.route}
+				{@const route = routing.route}
+				{@const color = ROUTE_COLORS[routing.selectedRouteIndex]}
+				<div class="flex justify-between items-baseline mb-1">
+					<span class="text-xs font-semibold" style="color: {color}">
+						{routing.routes.length > 1 ? ROUTE_LABELS[routing.selectedRouteIndex] : 'Route Found'}
+					</span>
+					<span class="text-sm font-bold text-[var(--text-primary)]">
+						{formatWeeks(route.total_time_weeks)}
+					</span>
+				</div>
 
-			<!-- Leg details -->
-			<div class="flex flex-col gap-1">
-				{#each routing.route.legs as leg, i}
-					<div class="flex items-center gap-1.5 text-[10px]">
-						<span class="w-3 h-3 rounded-full bg-[var(--accent-blue)] flex items-center justify-center text-[8px] text-white font-bold shrink-0">
-							{i + 1}
-						</span>
-						<div class="flex-1 min-w-0">
-							<div class="text-[var(--text-primary)] truncate">
-								{stations.stationNames[leg.from_station]} → {stations.stationNames[leg.to_station]}
-							</div>
-							<div class="text-[var(--text-secondary)]">
-								{formatWeeks(leg.arrival_week - leg.departure_week)} transit
-								{#if leg.wait_weeks > 0}
-									&middot; {formatWeeks(leg.wait_weeks)} wait
-								{/if}
+				<div class="text-[10px] text-[var(--text-secondary)] mb-1">
+					Departs week {route.departure_week} &middot; {route.legs.length} leg{route.legs.length !== 1 ? 's' : ''}
+				</div>
+
+				<div class="flex flex-col gap-1">
+					{#each route.legs as leg, i}
+						<div class="flex items-center gap-1.5 text-[10px]">
+							<span
+								class="w-3 h-3 rounded-full flex items-center justify-center text-[8px] text-white font-bold shrink-0"
+								style="background-color: {color}"
+							>
+								{i + 1}
+							</span>
+							<div class="flex-1 min-w-0">
+								<div class="text-[var(--text-primary)] truncate">
+									{stations.stationNames[leg.from_station]} → {stations.stationNames[leg.to_station]}
+								</div>
+								<div class="text-[var(--text-secondary)]">
+									{formatWeeks(leg.arrival_week - leg.departure_week)} transit
+									{#if leg.wait_weeks > 0}
+										&middot; {formatWeeks(leg.wait_weeks)} wait
+									{/if}
+								</div>
 							</div>
 						</div>
-					</div>
-				{/each}
-			</div>
-
-			<!-- Animation controls -->
-			{#if routing.trajectoryPoints.length > 0}
-				<div class="mt-2 pt-2 border-t border-white/5">
-					<div class="flex items-center justify-between mb-1">
-						<span class="text-[10px] text-[var(--text-secondary)]">Package Progress</span>
-						<button
-							onclick={() => { routing.isAnimating = !routing.isAnimating; }}
-							class="text-[10px] px-1.5 py-0.5 rounded {routing.isAnimating ? 'bg-[var(--accent-green)]/20 text-[var(--accent-green)]' : 'bg-white/5 text-[var(--text-secondary)]'}"
-						>
-							{routing.isAnimating ? 'Animating' : 'Paused'}
-						</button>
-					</div>
-					<input
-						type="range"
-						min="0"
-						max="1"
-						step="0.002"
-						bind:value={routing.routeProgress}
-						class="w-full h-1 rounded-full appearance-none bg-white/10 [&::-webkit-slider-thumb]:appearance-none [&::-webkit-slider-thumb]:w-3 [&::-webkit-slider-thumb]:h-3 [&::-webkit-slider-thumb]:rounded-full [&::-webkit-slider-thumb]:bg-[var(--accent-green)] [&::-webkit-slider-thumb]:cursor-pointer"
-					/>
-					<div class="text-[9px] text-[var(--text-secondary)] text-center mt-0.5">
-						{Math.round(routing.routeProgress * 100)}% complete
-					</div>
+					{/each}
 				</div>
+
+				<!-- Animation controls -->
+				{#if routing.trajectoryPoints.length > 0}
+					<div class="mt-2 pt-2 border-t border-white/5">
+						<div class="flex items-center justify-between mb-1">
+							<span class="text-[10px] text-[var(--text-secondary)]">Package</span>
+							<button
+								onclick={() => { routing.isAnimating = !routing.isAnimating; }}
+								class="text-[10px] px-1.5 py-0.5 rounded {routing.isAnimating ? 'bg-[var(--accent-green)]/20 text-[var(--accent-green)]' : 'bg-white/5 text-[var(--text-secondary)]'}"
+							>
+								{routing.isAnimating ? 'Playing' : 'Paused'}
+							</button>
+						</div>
+						<input
+							type="range"
+							min="0"
+							max="1"
+							step="0.002"
+							bind:value={routing.routeProgress}
+							class="w-full h-1 rounded-full appearance-none bg-white/10 [&::-webkit-slider-thumb]:appearance-none [&::-webkit-slider-thumb]:w-3 [&::-webkit-slider-thumb]:h-3 [&::-webkit-slider-thumb]:rounded-full [&::-webkit-slider-thumb]:cursor-pointer"
+							style="--tw-ring-color: {color}; [&::-webkit-slider-thumb]:background-color: {color}"
+						/>
+					</div>
+				{/if}
 			{/if}
 		</div>
 	{/if}