There are a total of 8 Riddler Trophies in the Port Adams Subway and they can be found in the following locations:
Riddler Trophy 01
As soon as you get off the lift upon entering the Subway, look upwards to spot a catwalk over head. Grapple up here and then to the roof of the structure above the trains. Drop down into the office via the hole in the roof here to find the Riddler Trophy on a desk.
Riddler Trophy 02
This Riddler Trophy is in the side-area where the stationary Drone Tank we had to sneak by was located when we snuck through the area on foot. It can be found on a shelf here.
Riddler Trophy 03
When you reach the second ramp, look on the roof of the control room to find this Riddler Trophy .
Riddler Trophy 04
After going through the subway station you’ll find yourself in a room with three wooden walls we can drive through. Before exploring any of them, use a Batmobile eject or grapple to reach the top of the room to find a Riddler Trophy in a walkway above.
Riddler Trophy 05
After going through the subway station you’ll find yourself in a room with three wooden walls we can drive through. Head through the right hand wall first and move up to the construction. You’ll find this Riddler Trophy at the top of the stairs.
Riddler Trophy 06
From Riddler Trophy #5, look up to the top of the room to see some walkways and support platforms. You’ll find this Riddler Trophy up here.
Riddler Trophy 07
Keep moving along the set path from Riddler Trophy #6 and when you reach the sunken area, there is a platform on the north side of the room near the entry with the Riddler Trophy on it.
Riddler Trophy 08
Return to the room with the three weak wooden doors. This time go through the left hand door and climb the ramp inside all the way to the top. When you reach the edge of the platform look to the right to spot the Riddler Trophy here.