Simplify the following text for a Grade 12 native English-speaking person.
Original: It is believed that it consists of a single track and connects the Kremlin , chief HQ ( General Staff - ` Genshtab ' ) , Lubyanka ( FSB Headquarters ) and the Ministry of Defense , as well as numerous other secret installations .
Simplified: It is believed that it consists of a single track and connects the Kremlin , chief HQ ( Genshtab ) , Lubyanka ( FSB Headquarters ) and the Ministry of Defense , as well as numerous other secret installations .