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| Thoughts after two very frantic sessions 28/05/2018 at 12:52 #108308 | |
trolleybus
142 posts |
I've gone through London Bridge twice now, the first time from midnight until about 1800, the second time until I ran out of trains at about 0130. I quickly realised that attempts to run the sim single-handed without ARS may prove tricky, so I had full ARS on (except class 0), everywhere. These are my thoughts. First, London Bridge really is a tremendous addition to the SimSig stable. It's huge and complex, yet seems to contain very, very few bugs. It's certainly stable in a way that some of the sims weren't on initial release. This reflects very well indeed on the developers, timetable writers and testers. On both runs I managed to leave the simulation running on several occasions when I left the room. In fact I tend to do that. I usually try to multitask, so if I leave the room when something other than SimSig is on the screen I forget to hit P. This post is, therefore, about how the simulation (and ARS) copes when under severe stress; at times 118-120 trains. The first thing to note is that with delays turned off (both runs were in easy mode) ARS is very good. I'd say it's the best so far, handling the complex layout very well. There may be the odd, minor, regulation problem but the sim can be left for long periods and ARS will just get the job done. But once things start to go pear shaped then things escalate quickly, which is fair enough as ARS is not designed for such situations. The problems I noticed are as follows. London Bride LL. I had problems at London Bridge LL due to the timetable requiring platform sharing. The train on the stops was short so the permissive route wasn't needed, but then the TT did not have PS entries for the trains concerned (half of 2I59 after splitting and a few 2Kxx services), so that may be the explanation/resolution. Cannon St. throat. I had the odd occurrence of a Mexican standoff here, but resolvable by manually setting routes towards London Bridge or by replatforming. ACOA. A small number of trains reported ACOA for unknown reasons. Most, maybe all, were at L290. Two down trains (2L06 and 2L10) were reluctant to leave the station at Blackheath. Both had green signals towards the North Kent line and an expected departure time in the past, but they remained stopped, in one case for half an hour until I temporarily abandoned the TT. Trains booked to stop at Lee Spur Jn (presumably L301) are stopped at Hither Green and held there. ARS sets a route from L301 back onto the Up Slow, but it never sets one from L295 to L301. Finally, the biggest problem concerns Lewisham when stressed. Trains for Ladywell often found themselves unable to move as trains waiting at L262 were fouling the junction. The reason that a train was at a stand at L262 is because the train in Lewisham P1 requires the reversible. That line, or L253, has a down train waiting for Lewisham P2 - which is occupied by the train trying to get to Ladywell. It's resolved by routing the train in P1 via the Up Slow, but this deadlock occurred several times and could be prevented by not letting ARS set a route to L262 if the latter isn't showing a proceed aspect. And that's just about it. There were plenty of occasions when manual intervention was needed to resolve n-way soft loops (e.g. A is waiting for B, B is waiting for C, C is waiting for D which isn't A but is logically similar, for instance it's in front of or behind A). All of the above are minor, and my testing isn't realistic in the stress I impose on both the sim and ARS. I imagine that some of these problems are timing-related, so may be very hard to resolve. But it hardly matters. This is a great sim that will occupy me for many more days in the future. Log in to reply The following users said thank you: GeoffM, Stephen Fulcher |
| Thoughts after two very frantic sessions 30/05/2018 at 14:58 #108342 | |
Giantray
330 posts |
A very interesting post. In reality, the Signallers never had ARS at LBASC, even today with the majority of LBASC now at Three Bridges ROC on WestCad, there still is no ARS. So the Signaller was and still is very aware of avoiding potential "Mexicans". There are a multitude of locations and situations the Signaller would always have in the back of their minds. Some of it was learnt the hard way by them falling foul themselves, a lot was handed down from earlier generations of Signallers as was the way the area was worked. Sadly something never written down so a lot has been lost.
Retired Professional Railwayman (1981-2023); Pway & S&T (1981-88); Former Signalman/Signaller/ Signalling Trainer (1989-2023) [AB, TCB, Mechanical, NX, WestCad, Hitachi SARS]; Railway Historian (esp.SER, LCDR); Member of The Permanent Way Institution.. Log in to reply The following user said thank you: trolleybus |
| Thoughts after two very frantic sessions 08/06/2018 at 03:25 #108483 | |
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MrBitsy
121 posts |
Sounds like a standard day to me! Bristol Temple Meads ARS needs a lot of intervention even when the service is running to time. Partly due to teething problems after the recent upgrade.
TVSC Link 4 signaller - Temple Meads, Bath & Stoke Gifford Log in to reply |
| Thoughts after two very frantic sessions 08/06/2018 at 10:39 #108487 | |
Guts
586 posts |
MrBitsy in post 108483 said:Sounds like a standard day to me! Bristol Temple Meads ARS needs a lot of intervention even when the service is running to time. Partly due to teething problems after the recent upgrade.I'm guessing it's not the Resonate (formerly Delta Rail) ARS. The other one ARS is crap TBH. Doesn't work 'as advertised' around the country. Log in to reply |
| Thoughts after two very frantic sessions 08/06/2018 at 23:15 #108514 | |
GeoffM
6282 posts |
Guts in post 108487 said:MrBitsy in post 108483 said:I'm guessing the "other one" is the Hitachi/TRE ARS, the one that I worked on for years, the one you're calling crap. Thanks for that. By "around the country" I'm guessing you mean you heard various things on the grapevine rather than knowing first hand. As usual, there are many, many factors involved as to why ARS works or does not work - anything from poorly written timetables, to unsuitable historic layouts for the modern timetable, to local ops requirements, to insufficient TDs being provided for inbound trains.... etc etc.Sounds like a standard day to me! Bristol Temple Meads ARS needs a lot of intervention even when the service is running to time. Partly due to teething problems after the recent upgrade.I'm guessing it's not the Resonate (formerly Delta Rail) ARS. The other one ARS is crap TBH. Doesn't work 'as advertised' around the country. The ARS for Bristol is IECC ARS, ie Resonate. SimSig Boss Log in to reply |
| Thoughts after two very frantic sessions 10/06/2018 at 21:28 #108559 | |
madaboutrains
307 posts |
GeoffM in post 108514 said:Correct me if I am wrong please. I get in the impression that SARS/ARS is a 'off the shelf' product that in some locations need to be adapted in order to suit the user requirements. Its tested in simulator conditions and validation software to match needs of the locations but its use in the real world with problems like distribution, set swapping, platform changes, lengths of different trains and various other situations means it does not perform as expected compared to the simulation model? RIP Feltham Panel 1 Log in to reply |
| Thoughts after two very frantic sessions 10/06/2018 at 21:39 #108560 | |
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GeoffM
6282 posts |
madaboutrains in post 108559 said:Correct me if I am wrong please.IECC ARS and SA-ARS both have core software which is data driven - in fact the data is very similar between the two, though SA-ARS was more advanced (not sure if that changes since scaleable). Individual routes can have their priorities altered, and the predicted timings between TD steps can be manipulated. Neither ARS has a concept of train length so set swaps aren't an issue unless things don't fit in their booked platform (not just an ARS problem). Platform changes can be handled by SA-ARS in advance (whether by timetable alteration or using the user interface). As to why it works or not, as I said in my previous post, there are a large number of factors involved. In some areas IECC ARS is pretty dire; in other places the signallers trust and rely on it. SA-ARS has had a more rocky roll out, partly because most areas were retrofitted with SA-ARS instead of being planned from the ground up - interlockings particularly, where IECC ARS usually used SSI data with SSI written with ARS in mind; SA-ARS was often a bolt-on to old relay interlockings and in any case required additional safeguards to meet a high safety level. I just heard today that SA-ARS is performing very well in the parts of Birmingham New Street that have been re-controlled: this area was always contentious with naysayers saying "it'll never work" - but it apparently does, and well. SimSig Boss Log in to reply |
| Thoughts after two very frantic sessions 11/06/2018 at 03:09 #108567 | |
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MrBitsy
121 posts |
GeoffM in post 108514 said:Guts in post 108487 said:The ARS at Bristol is doing better day by day as its tweaked. Still have to be on your toes with it, but it is becoming useful rather than a hindrance on day 1 :-)MrBitsy in post 108483 said:I'm guessing the "other one" is the Hitachi/TRE ARS, the one that I worked on for years, the one you're calling crap. Thanks for that. By "around the country" I'm guessing you mean you heard various things on the grapevine rather than knowing first hand. As usual, there are many, many factors involved as to why ARS works or does not work - anything from poorly written timetables, to unsuitable historic layouts for the modern timetable, to local ops requirements, to insufficient TDs being provided for inbound trains.... etc etc.Sounds like a standard day to me! Bristol Temple Meads ARS needs a lot of intervention even when the service is running to time. Partly due to teething problems after the recent upgrade.I'm guessing it's not the Resonate (formerly Delta Rail) ARS. The other one ARS is crap TBH. Doesn't work 'as advertised' around the country. TVSC Link 4 signaller - Temple Meads, Bath & Stoke Gifford Log in to reply |