diff --git a/bin/train.py b/bin/train.py
index 3de61f7..f5fb54f 100644
--- a/bin/train.py
+++ b/bin/train.py
@@ -153,7 +153,7 @@ def build_parser() -> argparse.ArgumentParser:
     parser = argparse.ArgumentParser(
         usage=__doc__, formatter_class=argparse.ArgumentDefaultsHelpFormatter,
     )
-    parser.add_argument("config_json", type=str, help="json of params")
+    parser.add_argument("-c", "--config", type=str, help="json of params")
     parser.add_argument(
         "-o",
         "--outdir",
@@ -173,8 +173,10 @@ def main():
     args = parser.parse_args()
 
     # Load in parameters and run training loop
-    with open(args.config_json) as source:
-        config_args = json.load(source)
+    config_args = {}  # Empty dictionary as default
+    if args.config:
+        with open(args.config) as source:
+            config_args = json.load(source)
     train(results_dir=args.outdir, toy=args.toy, **config_args)