RDNA wrote:RDNA wrote:Mike Stone wrote:by Mike Stone » Sun Sep 10, 2017 5:43 pm
Can ARS "change its mind"?
No Mike, so far as I know ARS cannot cancel routes, it just sets them according to the conditions programmed in the "flowchart", often somewhat pretentiously called the "algorithm".
ARS does not have a 'mind', artificial intelligence has not been invented!
DB
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After which, JRB posted :-
"Not a mind, but an algorithm could do it. They just have not invested in one."
I beg to differ!
The sheer number of alternative actions and their consequences on a complex mixed traffic railway means that only an experienced human who actually cares about efficient train running can make the best educated judgement about regulating in the real world!
DB
... which is why it may currently be a case of something like "We could do it but we don't".
Regarding Mike Stone 's most recent ("Can ARS "change its mind"?") query, unless things have changed on this point in the last ten or so years
(which I much doubt : And provided that the Stafford control system is not different from IECC Classic in this respect), the answer to this query is (AFAIK) still in the name -
Automatic
Route-
setting Sub-system : ARS cannot
cancel a set route.
Barring a serious soft-or-internal hardware fault of some sort,
[and apart of course, from Train Operated Route Release 'cancelling' sections of route behind the train], set but 'unused' routes can only be cancelled
(remembering that, dependent on situation details, an Approach Locking time delay in releasing a route may apply) via the interlocking, and, AFAIK at present, this can only be by action of the operator, whether by cancelling the individual route, or use of a
Signal
Group
Replacement
Control or an interlocking's
Emergency
Signals
On
Control (or their equivalents).
ARS 'setting' routes does so only by making a "route request"
(for that is the terminology; well, in IECC Classic anyway) to the interlocking : - Just as with a manual operator route-'calling' action
(which, with an SSI, is also a "route request") : Unless an ARS-requested route is free to set in the interlocking, the request will elicit no response until the requested route does become free.
However the answer to 'Can ARS "change its mind"?' could be 'yes' if the situation was that where ARS is 'programmed' to cater for alternative routes or routing strategies, then, if an ARS Route Request is unsuccessful (perhaps after several repeat requests or after a given time period), or its strategy looks further ahead in comparing, say, degrees of presence or absence of trains on parallel lines
(e.g. differing levels of queueing /'congestion'), ARS then might 'change its mind' before a requested route sets, by requesting the setting of a different route(s) for a theoretically better pathing.
Perhaps worth mentioning that, naturally, a route being 'not free' in an interlocking can be caused, not only by an already set route or train position being in conflict, but also if the operator has either locked any points in one position which a requesting route needs in the opposite position, or has applied a reminder to a signal or 'button'-equivalent to purposely prevent a route(s) from being set by
any means.
Also that if there are any ARS Sub-Area controls (or equivalent) present, of which any one can then be 'turned off' to inhibit ARS from requesting route(s) from/in/on its(their) designated individual signal(s), area, direction, or line, such action does
not prevent manual route requests.
So, regarding Mike's question about route appearing to be set and then cancelled ahead of a train, with no knowledge of circumstances, ARS algorithms' considerations, or signaller's thoughts, I can only speculate that either :-
- a route request (ARS or manual) was successfully made, and then manually cancelled, or
- in link(s) between the interlocking and by whatever means that the appearing and disappearing of route was observed, either :- -
- - the end display might differentiate between routes that are set ready for use, and those which have been cancelled but are 'timing out' or
- - route could have actually been set all the time but there may have been some 'hiccups' somewhere in the link(s).