diff --git a/resources/tester/test_52_7c_legacy_roundtrip.py b/resources/tester/test_52_7c_legacy_roundtrip.py
new file mode 100644
index 000000000..e02ed795b
--- /dev/null
+++ b/resources/tester/test_52_7c_legacy_roundtrip.py
@@ -0,0 +1,78 @@
+# -*- coding: utf-8 -*-
+"""옛 종류 구조물 저장 왕복(PLAN 52-7c) — 저장 · 다시 열기 · 다시 저장 뒤에도 수 · 종류 그대로.
+
+옛 대피소 · 정차·작업장 · 차돌림곳(52-7 고르기 목록 뺌) · 종단배수 · 계류사방(52-8 숨김) 모두.
+임시 storage(tmp_path) · 라우터 PUT/GET.
+"""
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+import B05_Profile.B05_Profile_Structures_Router as router_module
+from B05_Profile.B05_Profile_Structures_Schema import structure_type_map
+
+PROJECT_ID = "52700000-0000-0000-0000-00000000007c"
+URL = f"/api/projects/{PROJECT_ID}/route/structures"
+LEGACY = ("refuge", "work_yard", "turnaround")
+
+
+def _client(tmp_path, monkeypatch):
+    async def project_root(project_id):
+        return str(tmp_path / "project")
+
+    async def invalidate(project_id):
+        return True
+
+    async def route_length(project_id):
+        return None
+
+    monkeypatch.setattr(router_module, "_project_root", project_root)
+    monkeypatch.setattr(router_module, "_invalidate_downstream", invalidate)
+    monkeypatch.setattr(router_module, "_route_length", route_length)
+    app = FastAPI()
+    app.include_router(router_module.router)
+    return TestClient(app)
+
+
+def _record(type_, at):
+    options = {}
+    for o in type_.options:
+        if o.default not in (None, ""):
+            options[o.key] = o.default
+        elif o.required:
+            options[o.key] = o.choices[0] if o.choices else 1
+    record = {"type_id": type_.type_id, "placement": type_.placement, "options": options}
+    if type_.placement == "interval":
+        record.update(chainage_m=at, start_m=at, end_m=at + 10)
+    else:
+        record["chainage_m"] = at
+    return record
+
+
+def _kinds(body):
+    return sorted((s["type_id"], s["chainage_m"]) for s in body["structures"])
+
+
+def test_옛_종류_저장_왕복_수_그대로(tmp_path, monkeypatch):
+    types = structure_type_map()
+    ids = [*LEGACY, *(t for t, v in types.items() if v.group in ("B", "D") and not v.managed_by)]
+    assert len(ids) >= 3 + 6 + 3  # 기슭막이 = pipe_points 정본
+    records = [_record(types[t], 20.0 * (i + 1)) for i, t in enumerate(ids)]
+    client = _client(tmp_path, monkeypatch)
+
+    first = client.put(URL, json={"base_revision": 0, "structures": records})
+    assert first.status_code == 200, first.text
+    opened = client.get(URL).json()
+    assert len(opened["structures"]) == len(ids)
+    want = _kinds(opened)
+    assert sorted(t for t, _ in want) == sorted(ids)
+
+    # 다시 연 목록 그대로 저장 → 다시 열기
+    again = client.put(
+        URL, json={"base_revision": opened["revision"], "structures": opened["structures"]}
+    )
+    assert again.status_code == 200, again.text
+    reopened = client.get(URL).json()
+    assert _kinds(reopened) == want
+    by_id = {s["structure_id"]: s["options"] for s in opened["structures"]}
+    assert {s["structure_id"]: s["options"] for s in reopened["structures"]} == by_id