diff --git a/flatland/envs/rail_generators.py b/flatland/envs/rail_generators.py
index 5af4a079b1b6d210a395896df5d577c1c7a16267..d6e1c34f0bd2fb9b0694b16bdfa93b3d00e4ff2d 100644
--- a/flatland/envs/rail_generators.py
+++ b/flatland/envs/rail_generators.py
@@ -572,7 +572,7 @@ def sparse_rail_generator(num_cities=5, num_intersections=4, num_trainstations=2
             nodes_per_col = int(np.ceil(nb_nodes / nodes_per_row))
             x_positions = np.linspace(node_radius, height - node_radius, nodes_per_row, dtype=int)
             y_positions = np.linspace(node_radius, width - node_radius, nodes_per_col, dtype=int)
-            city_idx = np.random.choice(np.arange(nb_nodes), num_cities)
+            city_idx = np.random.choice(np.arange(nb_nodes), num_cities, False)
 
             node_positions = _generate_node_positions_grid_mode(city_idx, city_positions, intersection_positions,
                                                                 nb_nodes,