Restructure train/: nest shards into chunk subdirs (batch 97/98)

Restructure train/: nest shards into chunk subdirs (batch 59/98)

Restructure train/: nest shards into chunk subdirs (batch 58/98)

Restructure train/: nest shards into chunk subdirs (batch 57/98)

Restructure train/: nest shards into chunk subdirs (batch 56/98)

Restructure train/: nest shards into chunk subdirs (batch 55/98)

Restructure train/: nest shards into chunk subdirs (batch 54/98)