OpenBVE crashes in (the latest) Build 2021.02.16.

Hi!
 
I'm from Hungary, so there are Hungarian words in the attached screenshot of the OpenBVE Crash Log, too. Sorry for the "mixed" language in this picture.
I have downloaded the latest nightly build recently, because I wanted check whether the bug of Track.Brightness command is still exist in the .csv Routefile. Unfortunately I couldn't do this "checking", because when I started "play" the OpenBVE programme, it means, when the route & train loading reached the 100%, it threw me back to the main menu. I repeated this method / procedure, hoping that the problem was temporary, but this theory failed, unfortunately. :/ This prompted me to write this message, too.
About the original .Brightness bug: In fact, I don't even know if at all it's a bug or not. If the .csv Routefile contains the Route.Ambientlight and Route.DirectionalLight commands, it affects to the whole track, and it's okay. However there was no way I could produced the brightness differences between the stations and the tunnels. For the latter, the tunnel is still bright, despite I added "Track.Brightness 40" command for this section, only the external textures of my train became dark.
I have no idea, how to solve this problem. Perhaps, if there was a new command with this name "Track.Ambientlight ...", that would be a solution for lighting treatment... 
I hope you can fix this critical error, too. 
 
Thanks,
Andrew

The Crash Log file: https://photos.app.goo.gl/arLxz75sadgg5weYA

Not from official oB devs, but they're doing some backend change. They haven't finished yet, and the latest nightly build will crash.
You should download the latest stable build (v1.7.2.4), or an older Nightly Build (The safest is probably around 27 days ago, or late January)

Yeah, I'm somewhat in the middle of some very major internal plumbing work
I'm hoping to get this finished over the course of this week, and we can then figure out if anything else is broken.

(The local copy doesn't even build properly at the minute, hence why it's not been pushed to GitHub)

Specifically, this is to allow trains to be loaded via plugin.
Whilst this doesn't sound like much, at the minute there are effectively 4 copies of the train parser (main program, 2 editors and Object Viewer), and it's a nightmare implementing features when you have to remember deal with this.

https://github.com/leezer3/OpenBVE/pull/588

If you're curious
I think everything is now working, but I'm going to give it a few dats of testing and thinking before I drop it into the daily builds for everybody else to break horribly

Doesn't seems Klaxon is working, but that's pretty much it for now