[cfontes]

I've used custom made implementation in Java ( proprietary based on the owner thesis ) to optimize train crossings for big mining companies like Vale, BHP and Rio tinto, it was stressful but super fun work!

Lot's of money to be made on it too if you guys are interested, but it's super niche and hard to get into. There is a huge resistence from train controllers and other workers. I actually understand it because of the job loss involved but it was super cool being in a NASA like control center sorrounded by panels and monitors and seeing the trains moving based on code I and other wrote!

It was a just in time local optimization with lots of heuristics and business rules embedded into it. Basically impossible to reuse between companies or even railroads sometimes, the controller would then solve all the more complex crossing that involved either some lose-lose choice or a pre-defined business decision.

The train controllers are amazing at their jobs, it's super stressful and a single mistake can kill people or make the whole thing stop for weeks, with the software running it made it a lot less risky, one dude could control an area that needed 7 or more people without it, with minor interventions.

[exikyut]

That's awesome.

A comment on a recent thread about a train IT failure went on a bit of an interesting tangent about ahead-of-time network scheduling in (IIUC) the Netherlands' TURNI system - https://news.ycombinator.com/item?id=30902585

(The whole thread was a bit of a wide-spectrum ramble, as one might expect for a downtime event.)

So you're saying you were actually doing JIT routing as opposed to AOT? The linked system apparently precomputed the trip<->driver/conductor schedules overnight. I wonder if they're still using that approach today. It does feel like a JIT approach is much more amenable to handling the unpredictable non-spherical real world (eg electricity issues, track breakage, crashes at crossings, train malfunctions that block tracks (right on junctions >:D), etc).

This sorta thing is definitely beyond my own mental level :) but for reference, how would someone interested get their foot in the door in this area?

[cfontes]

So we thankfully didn't have to worry about conductor schedules another system our company built did it and we just worked on the assumption that the cow was spherical, this alone made a world of difference in segmenting whose head was exploding at which time.

All the rest was on us, failures, breakages, crashes (We never had one!!!), blocks were super interesting btw!.

So I got on it by chance, I just did interviews as a sport when I was in my early 30's so at some point I passed on this position, pay was awesome, lot's of travel involved, etc... So I joined and learned it all there, it was a small mom and genious software house that specialized on all types of JIT planning for railroads.

JIT was actually "THE" solution to it, because the controllers could just try it during the day, so let's say they new 18:00 was the worst and there was a huge trains comming in at that time with priority, he would just throw shit at the system to see how to same the most time sometimes, of course he knew how to do it by heart, but was it the "Best way" we could help him answering it super fast.

P.S: I am not ducth but I lived there for a while, I remember thinking about how much of a bad day it would have been if it was me, I knew exactly what the NS people were felling :D