There's quite a few pickups there that decided they should get hit by the train. I'm not putting this in the bugs section because there's really no "bug" to swat here. So what happened?

1. On the upper track, a slow rock train cleared a busy grade crossing at speed, coming from that track that goes straight off the right side of the picture.
2. This train, which had to stop in-picture to avoid plowing into the side of the rock train, resumed- but didn't reserve the crossing until after the rock train had cleared it.
3. In that split-second of crossing non-reservation, a handful of trucks decided that since the gates were rising, they should cross the tracks. Real drivers would probably have noticed the second train already accelerating towards the crossing and elected not to get in its path.
4. Unfortunately, their crossing time is way longer than the time it took this train to actually reach the crossing!
5. No, train-truck collisions aren't simulated, so no vehicles- or drivers- were harmed.

When trains approach this crossing at speed, there's enough time between crossing activation and train arrival for the trucks to get clear. However... if it were, say, a 10-track crossing, that wouldn't be true.

You can make something similar if you like, by making a really long grade crossing, with lots of tracks... or lots of crossing connectors. Or at least you can in Version 4.1 | v0.8.4a (b588), who knows when/if they'll find some way to stop this without making grade crossings way more computationally expensive than they need to be.

Helicopter Reporter: "Traffic on the 405 is backed up for miles. Dispute between a train and a angry truck driver caused the collision. Back to you Tom."

🤣 I will have to try that. 🤣

Oh! I found another accident waiting to happen! Pretty sure it'll be dismissed as technically difficult if I report it as a bug, but I'm reasonably confident that the devs periodically read these too. But there's something wrong with this picture...

... That train is moving at 24km/h, and it has entered the last 4-meter track block available to it. If it overruns, that other train is parked at the very near edge of that block- so that means this train is also about 4 meters away from a head-on collision.

... It's driving backwards at the moment, but that's beside the point.

Why do I say 4 meters? Because according to the train length field in the depot, each tile is 2 meters. And it's... oh, sorry, that's 3 meters from a collision.

In order to make a complete stop from 24km/h, or about 7 m/s, in just 3 meters, it needs to reach that stop in around 0.85 seconds. You can calculate exactly how long the train would take to move 6 meters at constant speed if you want, I can't be bothered to go more precise than an estimate. But while 7m/s in just under a second is below one gravity... it's about three times the decelerative force granted by friction with the rails, and when playing the game, it certainly looks like a sudden stop. Correction, it is. Here's roughly one and a half meters to collision, and still cruising at 6m/s (rounding down this time, instead of up).

To make the half-second stop necessary to avoid collision, it needs to decelerate at around 1.5g, which will make a mess of the cargo...

... Or not. Around a quarter-second stop, meaning it took roughly 3 hours to decelerate from 22km/h to 0km/h over a distance of one meter, and I found an angle from which the couplers are more readily visible.

If you want to rough up your railroad crews, you can do this too- just make sure the trains have to come to a complete stop- and not for their destination station- right at the bottom of a hill! The travel speed control doesn't consider the effects of terrain, causing it to brake late... Station approach uses a lower deceleration rate that makes for a smooth stop from even the steepest of hills.

You can even see it in how the smoke from the engine is roboteching...