How to use TreeObsForRailEnv in remote client?

When I initialize a TreeObsForRailEnv and pass it as the obs_builder_obj for the remote client, I get the following error:

# Relevant code chunk
tree_observation = TreeObsForRailEnv(max_depth=2)
observation, info = remote_client.env_create(obs_builder_object=tree_observation)
# Error
Traceback (most recent call last):
  File "", line 90, in <module>
  File "/anaconda/envs/flatland-rl/lib/python3.6/site-packages/flatland/evaluators/", line 200, in env_create
    _response = self._remote_request(_request)
  File "/anaconda/envs/flatland-rl/lib/python3.6/site-packages/flatland/evaluators/", line 165, in _remote_request
    raise Exception(str(_response["payload"]))
Exception: {'type': 'FLATLAND_RL.ERROR', 'payload': "'current_episode_controller_inference_time_min'"}

Hey @seungjaeryanlee,

It’s hard to say seeing only this part of the code. Could you point me to a (potentially private) repo with the full code?

I suspect this is a bug in the current pip version of Flatland which happens if a timeout occurs during the first timestep of an episode.

Are you maybe taking too long to do the first step after creating the env (timeout of 5min)? or to take the first step afterward (timeout of 5sec)?

hello,have you solved this problem? please give me some advice, thanks.

It is still not clear to me what this error is about, we could look more into it if we had a code sample or link to a gitlab issue where it occurs.