Here are some archival photos from the constructing of the first line of the Moscow underground.
Sometimes it is hard to distinguish where are the upper sides of the pictures and where are its lower parts, because photos are black-and-white and very old.
Cofferdams. The plate “Hairdresser’s” is in the background.
And in the foreground you can see a mine.
It is probably a headframe.
Workers are even without helmets, but it was normal for that time.