Trolley Drain / Davy Jones Trolley is a drain just outside of the Kippax Centre, to get into it you have to go down a rocky slope where you'll then be greeted with two sides with a double barrel on each. Over the hill you can get a look over a pool of water.
One side leads you to the forbidden pool (mentioned above) where many a trolley have been thrown in, floated atop and have sunk into. There's a small bit you can stand on so you're not hunched over in the tunnel, but from my experience the water will usually be just below ankle height, there is a ladder to the left of the tunnel you'll come out of where you can climb up but it looks very sketchy and one step of it is hanging off.
The other side leads you into the drains, if you've ever been in there and have seen Checkpoint Alpha, Bravo, etc or the "bub squad" graffiti then that was me and my mate @exemptionv
Each checkpoint is an open box/room where you can stretch around abit before continuing into the next set of tunnels, everywhere except the ground is covered in graffiti in most of the checkpoints, even the ceiling where you'll be greeted with "Why did you look up?" As you go further in the amount of graffiti will fade rapidly.Around the checkpoint charlie/delta mark the double barrel tunnels stop and you're greeted with a single bigger tunnel that you have to climb up into if you wanna progress further.
Next time I head there I'll make sure to get plenty of pictures, but heres one from panic that he took decades ago. This post was made to shed light on a drain that hasn't been given much credit online from what I've seen.
