We have posted plenty of articles about the Moscow Metro so, for a change, these are photographs of Metro tunnels of Saint Petersburg.
These tunnels opened back in 1955.
This is a ventilation connection between the air well and four stages.
This ventilator is supposed to work 24 hours a day.
Somewhere in the Saint Petersburg Metro, there is a construction which became abandoned several decades ago. Its cast-iron vaults are eaten away with rust.
The ventilator has been turned on.
Regular infiltration devices like those used in Moscow are not used in Saint Petersburg anymore. Local authorities prefer more ingenious equipmet for this purpose.
Many years ago it used to be a research laboratory.
A hermetic door.
This stage opened not long ago. Here, instead of tubing, they used concrete blocks.
Another hermetic door.
The view from the second floor.
Location: Saint Petersburg