The company I work for runs networks on trains. We pay at least 10x for all our components (switches, APs, cables etc.) for exactly this reason; everything needs to be certified a bunch of times. And since there’s so few people buying these devices they’re often buggy and work much worse than commercial off the shelf hardware.
Interestingly, you can slap just about anything you want in a bus without a second thought.
Most off-the-shelf hardware isn't going to pass EN50121. Your hardware might be buggy and user unfriendly, but a 8KV chassis discharge isn't going to take it out.
Indeed. I understand why some of this is necessary, but a lot of it seems to be a kind of process bleed, where "how we do things" in on part of the system just gets copied across without any real thought as to whether it's really necessary across the whole system.
One of the more interesting aspects of working in safety critical software was the thought that went into how to architect a system to minimise the amount of it that needed to be built to the highest standards so that we could focus the effort in the most effective way.
Interestingly, you can slap just about anything you want in a bus without a second thought.