test wise you’d be amazed at what old controllers end up at surplus places or on eBay.
NO old surplus controllers are being reused in the industry.
The overriding mandate in EVERY train design system is "fail to safe". Trains are unique in that they have a reliably safe fail mode - brake, as fast as you can, so fast that the wheels heat up and weld to the tracks. Another train could come along and hit them, but that's another incident, unrelated to the current danger.
Cars doing that can get rear-ended as a result. Planes would de-elevate rather dramatically. Bicycles would throw their riders off.
The industry (and specifically, the light-rail aka people mover train industry) is so safety-conscious that railroads write additional safety regulations to be added to the FRA rulebook.
> People who work for the railroad are smart, and have a lot more experience with trains than your average Lambda School grad, so I'll defer to their judgemental
That's a very idealistic view of the world, I don't think reality would agree. Ego, indifference, and plain incompetence are extremely common in every industry, then add onto that the fact that hardware companies are already notoriously bad at software, and then you can double the risk for entrenched companies that have little pressure to be proactive about these things.
This is exactly the kind of lax response I would intuitively expect from a company of this nature. I say that as I glance over at Boeing.
It needs local proximity RF which was probably considered an out of scope risk in the initial design but is more and more likely to be available by accident as newer RF devices have more defined by software.
Except for 1 train in the US, no passenger trains use this function. It is only for long freight trains.
If you block it, the train still brakes…. Just the propagation is at the speed of sound instead of speed of light. Functionally, it doesn’t matter.
You can theoretically cause the brakes to apply, but then this system just gets cut out anyway. It’s not really required.
DanAtC•6mo ago
linusg789•6mo ago