An implementation of Tacotron speech synthesis in TensorFlow configured to run on google cloud machine learning engine. this is the same implementation here Tacotron but changed a little to run on google ML Engine please refer to the linke above for source implementation details and how it works
--Output_dir this is replacement for --base_dir where you define the cloud storage path to your ouput directory
--input
here you define the path to your bucket on cloud storage where you have training data (train.txt)
ex: gs://BUCKET_NAME/training/train.txt