The command crashes with the following error:

OSError: [WinError 6] The handle is invalid

Currently the only work around is to not use reinit and instead call your training script in it's own sub process:

import os
for i in range(10):
    os.system("python train.py args")

The underlying cause is the way Windows handles file descriptors and inheritance. We're currently working on a major refactor that will change the ways in which file descriptors are used. If you're hitting this issue, please follow this thread and we'll update everyone once this is fixed.