diff --git a/assets/src/models/shuttle.ts b/assets/src/models/shuttle.ts
index 026b99e9e..7eced30c9 100644
--- a/assets/src/models/shuttle.ts
+++ b/assets/src/models/shuttle.ts
@@ -1,4 +1,48 @@
-import { Vehicle } from "../realtime"
+import { RunId, Vehicle } from "../realtime"
+
+export enum ShuttleVariant {
+  // Rapid Transit Lines
+  Blue = "Blue",
+  Green = "Green",
+  Orange = "Orange",
+  Red = "Red",
+
+  // Other Shuttle Types
+  CommuterRail = "CR",
+  Special = "Special",
+}
+
+export const shuttleVariantFromRunId = (
+  runId: RunId
+): ShuttleVariant | null => {
+  switch (runId) {
+    case "999-0501":
+      return ShuttleVariant.Blue
+    case "999-0502":
+      return ShuttleVariant.Green
+    case "999-0503":
+      return ShuttleVariant.Orange
+    case "999-0504":
+      return ShuttleVariant.Red
+    case "999-0505":
+      return ShuttleVariant.CommuterRail
+    case "999-0555":
+      return ShuttleVariant.Special
+    default:
+      return null
+  }
+}
+
+const prefix = (variant: ShuttleVariant | null): string => {
+  switch (variant) {
+    case null:
+      return ""
+    case ShuttleVariant.CommuterRail:
+      return "Commuter Rail "
+    default:
+      return variant + " "
+  }
+}
 
 export const formattedRunNumber = ({ runId }: Vehicle): string => {
   if (runId === null) {
@@ -8,24 +52,5 @@ export const formattedRunNumber = ({ runId }: Vehicle): string => {
   const [area, run] = runId.split("-")
 
   // Remove leading zero from the run portion
-  return `${prefix(run)}${area} ${run.slice(1)}`
-}
-
-const prefix = (run: string): string => {
-  switch (run) {
-    case "0501":
-      return "Blue "
-    case "0502":
-      return "Green "
-    case "0503":
-      return "Orange "
-    case "0504":
-      return "Red "
-    case "0505":
-      return "Commuter Rail "
-    case "0555":
-      return "Special "
-    default:
-      return ""
-  }
+  return `${prefix(shuttleVariantFromRunId(runId))}${area} ${run.slice(1)}`
 }