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If you aren't using the car ride anywhere else you're still taking an object slot (but it's a ride object not a scenery object). You're also using a ride slot for every car you place, and several more map data slots than a scenery item would take. The only thing you save is a single scenery slot (although technically you could put the car object sprite into a large scenery object that you're already using so it doesn't take any extra slots. This is a bit bothersome though.).

If you actually want a real ride vehicle, that's the way you do it. But for cars, I think most people would use scenery objects unless you want them to move.

Small scenery objects have a number of flags that dictate which parts of the tile they occupy. An object can be full tile, quarter tile, half tile, 3/4 tile, or diagonal (which means it occupies two diagonally opposing quadrants of the tile). Any full tile object will be counted as cover - it does not have to be a roof (I don't think the game makes a distinction between roofs and other scenery), and there doesn't seem to be a requirement for any walls either. If there exists a full tile object above the ride track, that tile is considered to be covered. Large scenery objects don't have these flags and cannot occupy less than a full tile.

I had some appear by accident once but I don't know what I did to create them. I think it was probably the result of a bug.

They've worked in all situations for me too. The other kind of corrupt element is mostly for vanilla compatibility - there is rarely a reason to prefer it and pretty much never a case where you'd need it. The "rides set type" command does exactly the same thing as the arbitrary ride types cheat. It used to be quicker, when you had to select the ride type through a spinner, but now that there's a dropdown I no longer use it.

There is in the source code. But I think most people do it by trial and error. I had a brief look at the source but going through by hand and calculating the length would take far longer than running the ride on fast forward to see if the trains get out of sync. It's a tedious process whichever way you do it - I thought about adding a console command to show track length but I never did.

Because the wild mouse treats that piece as a spinning control toggle. This should be a special case; the wild mouse is the only track on which boosters will not work, because there are no boosters. As soon as you switch the track style to wild mouse, every booster piece turns into a spinning control toggle piece. As for the reason why it's not reaching full speed, I don't think this is to do with the train but the track style. I think the booster acceleration is different on different tracks, but someone else would have to confirm as I've not looked at it in too much depth. If you put a longer section of booster it should reach the specified speed.

Both of those work for me. That's probably due to the trains having differing mass.

Exactly this. It is. That's why I'm not recommending that you do it, just pointing out that it's possible. It's a real pain to get right - the two parts of the train must cover exactly the same distance during a circuit, or they get out of sync and the ride stops working. There's a tutorial here. This also a more complicated hack; OpenRCT2 does not have a cheat to do it, so you'll have to use a debugger, hex editor, or similar tool to accomplish this

It does not have booster sprites. That's a spinning control toggle. The booster piece is actually the same track piece as the spinning control toggle, the game just changes the behaviour based on the track type. On wild mouse track, it functions as a spinning control toggle, and on everything else it behaves as a booster. This had to be done because it is impossible to add a new track piece to the game without a new save format, so they had to repurpose an existing one that most track types don't use. What do you mean "coded to work with boosters"? Object files don't contain code. Can you give an example of a train that doesn't work?

No you don't. You are making the track invisible anyway, so there's no reason to merge (if you use a track piece that is not supported on a given track style, it still works but the missing piece will not be drawn). In any case, the steel wild mouse track has all the same track pieces as the wooden wild mouse and does allow brakes, so I would recommend using that instead. You can always switch the track type back again after you've built the brakes (you can do the same for diagonals, or really any track piece you want - you only need to merge if the track is supposed to be visible). Unfortunately not. You can get this effect using a shoestring, but a shoestring is very complicated to set up and IMO not really worth it for something so simple. Another option is to put brakes just after the turn, then add a few invisible cars in front of the rafts so that the brakes are hit during the turn. Of course, you then have to account for this delay everywhere else you used brakes. It's also not an easy hack to set up - unlike a shoestring this can't be done with cheats, and is less flexible but it requires a lot less trial and error. This is called breaking out. Thing is, there are no eddies on your river left channel so there is no place to break out - once over the lip, the rafts aren't stopping until they wash out at the bottom. I would have the rafts follow the flow of the river, as they do now, but place brakes where the hydraulics would form, because these would slow the raft IRL. I'd have it drop over the first ledge and then slow down to ~15mph in the pool at the bottom. Ideally you would brake slightly in the turn before the slide, but as noted above that's not easy to do so I'd skip it and just put brakes at the bottom of the slide. Then more brakes once they turn out of the flow. The main thing is to not have the rafts going really fast on flat water.

It's forced perspective - the track is not connected but the two ends are lined up so that they look connected from that angle. The ride is non-functional - I did build one that was functional, but I couldn't get it to work consistently. The synchronization has to be perfect for the illusion to still work with a train running.

Yeah, I used s-bends on mine. There just isn't anywhere on OP's waterfall where one would fit.

There isn't. The wild mouse has all the smallest drops available. Also, as @Deurklink pointed out, the track type doesn't matter if you're going to make the track invisible since you can use any track piece anyway. It's not as abrupt. Having a raft that is carrying some momentum navigate hairpin turns looks very wrong because they can't do that IRL. You need to think about the physics because the game is simulating a coaster, not a raft. You have to think how a raft would behave and try to mimic it. But I don't think you need to insert an S-bend anywhere on that course, the hairpin turns are fine. The rafts should not be carrying too much speed through the dogleg because the preceding drop is near vertical and most of the energy would be absorbed in the landing (which is why I suggest adding brakes). Following the large slide at the end of the rapid the rafts are going very fast, but even a large turn looks out of place here - they should continue straight for a few tiles until they have slowed down.

That's correct, the executable isn't required. But the assets are.

That looks like a terrifying section of rapid to be running in a raft. That first drop onto rock and the siphons on either side of it do not look pleasant. I'd suggest you put brakes at the base of the drops because the rafts aren't losing their speed quickly enough. They should accelerate down the drop and then slow down quickly at the bottom. Another thing you can do is to put another loop of dinghy slide track running on test mode underground. The noise the boats make sounds a lot like rushing water.

OpenRCT2 has always required the original game assets. If you were able to play it you must have them from somewhere; it sounds like the config file might have got deleted and you need to point OpenRCT2 to the location of your RCT2 files again.

As far as I'm aware this issue has been present ever since the LightFX were merged. I don't know if it existed before then - I never noticed it. The LightFX are very buggy - sometimes I find the lights don't work at all. I had a look for the source of the issue once but I never did find it.

You're more up to date than the server, so the best option is to wait for the servers to update (it doesn't usually take too long). If you really want to play now, you'll have to install a slightly older version of the game.

The plan is to add all the relevant track pieces. Loops, half loops, large half loops, corkscrews, barrel rolls, quarter loops, and large steep-to-flat are still to go in. S-bends and helices were added since this post was made. But I'm not working on it right now, I don't have much time available and it's not really worth it for something most people won't want. I'll revisit it when there's a new save format. Wait, what file is this? That's exactly what I did. This is a fork of the game, not develop.

No RMC currently has a loop, and the game doesn't have overbanked turns so those aren't an option. Only corkscrews and barrel rolls are conspicuously absent, but I don't have those pieces on the RMC track yet so I had to do a layout without them. There are two RMCs without inversions so it's not that unrealistic.

You're missing two steps. Firstly, it doesn't look like you actually merged the tracks. In the final screenshot, you need to click the build track button so that you have a junior piece overlapping with the first wooden piece. Then you select the end of the wooden track and do the same. Secondly, you need to put the ride in boat hire mode so it will let you open it with an incomplete circuit, or else complete the circuit with a dummy track.

Here's the relevant code

It can be but it's not always necessary. If you want intersecting scenery it's much easier to use zero clearance than the tile inspector. The tile inspector is often necessary for track if you want to place tracks at intervals of 0.75m instead of 1.5m, of if you're placing them in such a way that they would otherwise merge and make it impossible to get them where you want.

It's not a real coaster.