Paramedics carry an injured woman from a subway station after a rush-hour train derailment in Moscow (AP)

Investigators say they have detained two Moscow subway workers in the wake of a deadly rush-hour derailment that killed 22 people and injured 136 others.

Russia's major investigative agency said in a statement today that it had detained a senior track foreman and his assistant.

More than 1,100 people were evacuated yesterday after a train derailed between two stations in western Moscow. The rescue operation lasted more than 12 hours.

There is another line under construction nearby and the switch was to direct the trains to a new tunnel once the line is launched.

The two men have been questioned, and the investigators are preparing to file unspecified charges against them, the committee's spokesman Vladimir Markin said.

The Russian capital's airports and transit systems have been a prime target for terrorists over the past two decades, but multiple officials vigorously dismissed terrorism as a possible cause.

In recent months, subway workers have complained of declining safety standards in the system and disorganised measures for aiding stricken passengers.