Quicksand Fans

Boggy: You are right. I misremembered. (40 years will do that)

Fred: I'm pretty sure tar comes in all manner of thicknesses. You can get it thin enough to pour at room temp, or thick enough that you can almost cut yourself on it when it breaks. If I'm not mistaken, I have seen broken tar that looked a bit like dull broken colored glass. I think the difference is the length of the carbon chain, with the shorter chains making thinner tar, and longer chains making tar with a slower flow and higher melting temp.

It is possible to have a tanker truck full of tar that flows nearly as well as oil, and a dump truck filled with tar in solid form at the same temp. Heating any tar softens it, until it is runny.

I have quite a unique idea: a train derails in the Everglades, and the driver, a girl, falls in the mud while looking around, you can imagine what happens next...

I actually have a story written about that, but I don't know whether to release it or not.

I've actually had the train idea in mind for a long time now, but I haven't been able to paint it out.

If a train derails in the swamp, I'm thinking you'd need to lose a few other characters before you get a lone woman out away from the wreck. Now, with a swamp, this can be seriously easy, in that swamps are unforgiving places with animals big enough to eat you. (and from what I understand, Florida now has boas out there (escaped or released pets) that are big enough to kill and eat gaters. A few more years and I'm pretty sure they'll have 'em big enough to eat people too!

I'm pretty sure I've seen more than one person mix snakes & quicksand for fun and fantasy...

I have a relative who drives a train. From what I hear, it's really a guys-only group. 2 or 3 to run a train, though, and a dead-man switch to stop the train if nobody stands on it. Usually some negative emotions between the engineer and the driver, from what I understand.

There are other reasons to be out in a swamp. Someone with the wrong amount of swamp knowledge could think she knew enough to go out there alone, and such a person could easily inherit some property that would be off the local roads a bit. (or maybe she wants to pull a fast one on a real estate deal, but needs to have some knowledge of the land before she tries to sell it)

Lots of former railways have been and are being converted into hiking trails. Some forlorn rail employee could be tasked with taking pictures along a line, in preparation for just such a conversion. They might even give her a truck with one of those little railway carts loaded on it, but if it's manual and her partner did not show, it would be useless. (It could also be motor driven, but not start, or it could run easily, but just off the road is a bridge that is out, or just a piece of rail missing, so the cart would not be useful) If it's a bridge that is out, and she walks across the water that doesn't-really-flow beneath it, and the bed below said water seemed solid, it might be just the thing to keep her from paying all that much attention at the next such crossing...

It could be that a bridge is out, and she can see a gator or something on one side of the tracks, but not the other, but for whatever reason she can't quickly get back up the other side (a deep ditch runs down that side, for example) as she walks along beside the deep creek, it could look like it gets shallow up ahead, but the dry and easy part of the path seems to diverge a bit more than the creek, so after a bit she loses site of the rail. Worse still, she could come to a patch that softens unexpectedly, but has dryer land on the other side, encouraging her to move forward and not back to the rail. When water hides your footprints, it's really easy to get lost...
Swamps make for a fun setting!