When the software meets the hardware
In article ,
Clive Page wrote:
On 21/01/2019 10:02, Recliner wrote:
Engineers commissioning the new generation of software-enabled trains are
facing the problem that pretty well every system, and even sub-system, on
their train is computer controlled with its own software. This also has to
interface with the train’s third party software based systems.
I travel quite often on the new-fangled Siemens class 700 trains on
Thameslink, which are fitted with passenger information screens at
intervals in each carriage. Almost every day I travel I'm on a train
where some or all of these screens fail, most often going completely
blank part-way through the journey. Sometimes the screens spring back to
life at City Thameslink or Farringdon when the power source is changed
and I guess some parts of the system are rebooted, but not always. I
wonder if the train companies are even aware of these problems - there's
no obvious way of reporting them.
I was surprised that in most cases when the screens ail the audio
announcements of stations continues as normal. I had assumed that the
simplest way of providing audio and visual information was to generate
them from the same system, but obviously they have at least partially duplicated things.
Yes, that is surprising. Presumably the same data feeder system is used,
but the computerised visual and audio subsystems are different, maybe even
from different sub-contractors.
If it's like the train PIS systems I have worked on then they are
almost certainly part of the same system, but the audio playout will
be sent from the PIS controller audio output direct into the train PA,
whereas the displays will be distributed through a separate output via
one or more intermediate controllers which feed the screens. It will
be something in the latter chain that is failing.
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