diff --git a/Dockerfile b/Dockerfile
index c011b22..efb07ee 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,3 +1,4 @@
+#Dockerfile of branch mcp/train
 ARG FROM=ubuntu:bionic
 FROM $FROM
 
diff --git a/pre-build.sh b/pre-build.sh
index 5cbed9d..f717c94 100644
--- a/pre-build.sh
+++ b/pre-build.sh
@@ -8,8 +8,7 @@
 GERRIT_NAME=${GERRIT_NAME:-$(git remote -v | sed -n -e 's|^origin[[:space:]]\+\([[:alpha:]]\+\)://\([a-z0-9\-]\+\)@\([a-z.:0-9]\+\)/.*(fetch)$|\2|p')}
 GERRIT_HOST_PORT=${GERRIT_HOST_PORT:-$(git remote -v | sed -n -e 's|^origin[[:space:]]\+\([[:alpha:]]\+\)://\([a-z0-9\-]\+\)@\([a-z.:0-9]\+\)/.*(fetch)$|\3|p')}
 HORIZON_LIB_REPO="${GERRIT_SCHEME}://${GERRIT_NAME}@${GERRIT_HOST_PORT}/packaging/sources/horizon"
-GERRIT_BRANCH=${GERRIT_BRANCH:-master}
 
 git clone ${HORIZON_LIB_REPO}
-cd horizon/ ; git checkout ${GERRIT_BRANCH}
+cd horizon/ ; git checkout mcp/train