diff --git a/.gitignore b/.gitignore
index 2f1f81d1ba05de2544aeb53d61d2a222b59de31f..ce15e015aebdfab2e4b8a07f3633104ed3d2107b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -119,3 +119,5 @@ test_save.dat
 .visualizations
 
 playground/
+**/tmp
+**/TEMP
\ No newline at end of file
diff --git a/flatland/envs/persistence.py b/flatland/envs/persistence.py
index ca23b8d13da49134af2e415d3e713023bf798b3a..188ac7c2f1ea2e0c9ea9f637670f154bb54e2518 100644
--- a/flatland/envs/persistence.py
+++ b/flatland/envs/persistence.py
@@ -2,6 +2,7 @@
 
 import pickle
 import msgpack
+import msgpack_numpy
 import numpy as np
 
 from flatland.envs import rail_env 
@@ -22,6 +23,7 @@ from flatland.envs import malfunction_generators as mal_gen
 from flatland.envs import rail_generators as rail_gen
 from flatland.envs import line_generators as line_gen
 
+msgpack_numpy.patch()
 
 class RailEnvPersister(object):
 
@@ -308,4 +310,4 @@ class RailEnvPersister(object):
         self.height, self.width = self.rail.grid.shape
         self.rail.height = self.height
         self.rail.width = self.width
-        self.dones = dict.fromkeys(list(range(self.get_num_agents())) + ["__all__"], False)
\ No newline at end of file
+        self.dones = dict.fromkeys(list(range(self.get_num_agents())) + ["__all__"], False)