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Comment by rmoriz | Hacker News Reader

Axle counters are "positive only" systems e.g. if the numbers don't match or the counter resets, it will report an error and the next train needs a special safety order to enter the track section. So if you manage to combine a 256 axle train, it will just slow down everything on its way and cause chaos, but no accidents.

In the old times there was a manned caboose car at the end which job was to ensure the completeness of the train (and that switches are cleared).

Here's an example of such an SBB car decommissioned some centuries ago http://www.bahnbilder.de/bilder/gueterwagen-266906.jpg

Video (1986) https://www.youtube.com/watch?v=ev4szZ4iNTY

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> decommissioned some centuries ago

Decades, perhaps? (A decade is ten years; a century is one hundred.)

That makes good sense.

Still, given that the warning was issued quite explicitly it would seem that the designers of the operations guide definitely thought it was possible to have a train that long. Otherwise, why bother with the warning?

Because you have to cover all possibilities, even if they are highly unlikely. It's sad most people mistake this for weakness of a system.

> It's sad most people mistake this for weakness of a system.

I don't think that conclusion is warranted.

Well, maybe. I've seen a lot of "Hyperloop" fans who don't know basics about transportation systems (planning, technology, financing). So maybe I'm overly aggressive here. Sorry.

I've re-written a bunch of fuel quantity calculation software for a small airline, the degree of planning and verification that went into that totally blew my mind, it completely changed my way of thinking about writing any piece of software and even now I have to catch myself not to 'overthink' the solution to some problem.

As soon as there are lives on the line the amount of thinking about undefined situations skyrockets. Even so, given that the system fails 'positive' (as in: it can't register 'no train' when there is a train, it can only register 'train' when there is none) I'm quite impressed with the foresight to even think about that exact possibility occurring.

Another field where you see this kind of planning is in medical electronics and software systems.

The medical electronics you have seen must have very little resemblance to the equipment I use. Buggy, terrible UI and poor design.

Hm. Interesting. I've had - unfortunately - a lot of close up time with a bunch of high tech around one of my children and without exception that stuff was very well designed and did not hick-up even once over a whole pile of weeks. (Neonatal ICU.)

I've also bought some medical electronics surplus for parts in the past and it was absolutely bullet-proof. Top quality.

Try the radiology department. Brand new hardware and software from Siemens, GE or Philips. Particularly GE and particularly MRI interfaces. Broken code, and just plain terrible design choices like typing "1" for on and "0" for off. Type in "3" and it crashes, except when its occasionally allowed on non bools. Ultrasound interfaces are so unbelievable horrid that they should win any competition fairly easily. On on current model machine - touch screen, track ball, hardware sliders, physical buttons, software buttons and a track pad. connecting that to the network was unpleasant.

Edit: Im just taking an infusion pump to be serviced. This model is well liked. However when you want to deliver a drug bolus at a very specific time point during an MR scan the pump may deliver it, or it may give and error as its timed out. There is no way to tell prior to pressing "bolus". Not ideal.

> Another field where you see this kind of planning is in medical electronics and software systems.

Maybe sometimes...

https://www.youtube.com/watch?v=2o8MDCIlOEk

That should be reason enough for a claim.

Ya, I remember those. My friends and I would always wave to the cabooseman (I doubt that's the right word, but I really like it) as it went by, and he would usually wave back at us.

In Britain, he'd be called a guard or brake-man, and rode in the brake van.

The US probably has a different term.

Ironic since "van" means the front, as in vanguard.

I realize you weren't being serious, but this van is an abbreviation of caravan, which ultimately has its origins in Persian: In 16th cent. carouan, < Persian kārwān, in same sense. Found in medieval Latin carvana (Hoveden), caravanna, caravenna (Matt. Paris), and French carvane, from Crusading times, but apparently not in English before 16th cent. The form caravan was perhaps caravane from French.[1]

[1] http://www.oed.com/view/Entry/27717#eid10166797

In the U.S. that would the train's rear conductor or a brakeman, basically the conductor's assistants. In the days before vacuum brakes the rear conductor would have the job of reading lantern messages from the front conductor (in the locomotive) and then dispatching brakeman to walking along the train car roofs and individually setting the brakes on each car.

That sounds like a pretty dangerous job.

The railroad industry has a very sordid history of killing its employees. All the way from track construction to actual operation.

Even in this 1955 fire training video you can see they care more about the locomotive than the safety of the crew: https://www.youtube.com/watch?v=hkUQ3rTfU4s

tldw: crew were expected to enter the confined area of the engine room in the middle of a fire and turn at least two valves (that have complex interactions with each other) filling the same confined area with CO2.

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