> I apologise for being so dense. I wonder if this is it: I'm entering the caverns by taking the train to a western side track and heading northeast. When I get to where I think I should pick up the train, nothing. I don't hear any rumbling from the cart. I've also tried to re-enter the mines from where the stream from the red caverns lets out and no luck. Is this the path to the northeast right way to enter the mines?
> Interestingly, when I return to the spot where I got off the train it's still there. Before getting to the western side track, there's a spot where you can try to jump up to the ledge to the east. It's too high to reach. (Do I need the crate from GOA???) Any thoughts or help would be greatly appreciated. Thank you!

Ah, I think I know where you lost it.

First off, make absolutely sure the barrier past the side track is down. It'll require using the circular plate found just west of the southwest yellow room, and THEN ramming the barrier with the cart.

Once the barrier's down, DON'T take the train down the side track; you want it to keep moving. Instead, you should be able to jump DOWN off the track to the path below before the side track appears. (This way, the cart will keep moving without any barriers in its way.)

(I don't know what's with the ledge to the east; I know there's a too-high ledge after you catch the cart at the end, but I can't remember that on the way to the caverns...)

Hope this makes sense.

-Mandi