19 ms·
A lot of it is reduced BOM. You can get a more robust solenoid lock and control it with a microprocessor for less than the cost of a robust, fully mechanical s
by gumby 3y ago
A lot of it is reduced BOM. You can get a more robust solenoid lock and control it with a microprocessor for less than the cost of a robust, fully mechanical system, which is a system that needs mechanical maintenance and is subject to all sorts of false inputs like people putting all their weight on a lever.
Buttons flush with the surface or low profile levers such as the ones shown in the picture can be more robust against certain mechanical attacks simply by having lower weight, lower travel, and being smaller (don’t need to exhibit mechanical advantage).
I’m a fan of simple mechanisms with no software in them whenever possible, but I don’t have to deal with the cost and reliability problems.
- Sakthimm 3y agoWon't a solenoid lock with microcontroller circuitry have a higher risk of failure due to water damage, power surges, and other factors(software bugs, hackers, cosmic rays!), in addition to wear and tear of a mechanical lock?
- gumby 3y agoProbably not for some of the reasons described. The maintenance issues are part of the customer TCO. Nobody (neither mfr nor customer) takes this path for the sex appeal. This is a B2B product (train car) so BOM and TCO drive everything.
- kwhitefoot 3y agoThe problem here is that the customer is not the passenger.
- gumby 3y agoWell, it’s not such a big problem as it is in, say, health care. It’s in the train co’s interest to have working toilets (not too many, because they displace seats but some) and have them reliable and easy to maintain (else costs go up, maybe even they need more per train). This is why they care about a denial of service attack (btw an electronic one can tell the conductor when the toilet is locked for a grossly atypical duration). So to that degree the interest of the carrier and the passenger are aligned. This applies to most of the carriage decisions (robust seating, working doors and brakes, and so on).
- Beldin 3y ago> It’s in the train co’s interest ... But the if the trains pass first inspection, then it no longer is a development issue but a maintenance issue. [1] It's not as if train companies can afford to run a statistically significant number of carriages from different suppliers to see which one gives them the actual best bang for buck 5 years down the road. [1] Rule-proving exception: the Fyra trains. https://en.m.wikipedia.org/wiki/Fyra https://en.m.wikipedia.org/wiki/Fyra The short version: high speed trains failed and were eventually returned (2014) to the manufacturer for ~2/3rds of new price. (That's the exception part.) There have not been high speed trains on this traject since. (That's the rule-conforming part.)