diff --git a/protos/device_status.proto b/protos/device_status.proto
index 4a28234..e52b8b7 100644
--- a/protos/device_status.proto
+++ b/protos/device_status.proto
@@ -323,6 +323,9 @@ message Train {
 
   //线路id
   int32 lineId = 24;
+
+  // 列车标示号，全线唯一
+  string trainIndex = 25;
 }