Upcoming Games

(UTC times)


Full list
Add a game

Upcoming Events

No events to display

The big picture does trains, finally

You are here: Home > Forum > General > General questions, comments, and issues > The big picture does trains, finally

Page 1 of 1

The big picture does trains, finally 06/05/2013 at 20:15 #44386
slatteryc
Avatar
254 posts
http://www.boston.com/bigpicture/2013/05/by_rail.html

nice pic of Grand Centrals signalling overview in pic 14 ..... now that'd be fun for SimSig

Log in to reply
The following user said thank you: maxand
The big picture does trains, finally 06/05/2013 at 20:21 #44387
Temple Meads
Avatar
307 posts
That would be a nice and easy sim for single player
Username TIM in multiplayer
Log in to reply
The big picture does trains, finally 06/05/2013 at 21:44 #44389
Peter Bennet
Avatar
5402 posts
Found this.

Peter

I identify as half man half biscuit - crumbs!
Log in to reply
The big picture does trains, finally 07/05/2013 at 10:32 #44391
dmaze
Avatar
88 posts
#10 is probably the least inspiring picture of Grand Central Terminal I've seen. The other thing to remember about the dispatching center in #14 is that it's only half the station platforms -- there's a lower level with another couple dozen! I can't quite tell what the right-hand screen is; it must be the New Haven main line through the Bronx, but I didn't think it had quite that many sidings, and if the flyover where the Metro-North Harlem Line splits off is part of this area, it's not on the diagram.

The color scheme here seems to be typical for US dispatching screens from what I've seen (if you're in Boston, the announcer's booth at North Station has a more modern display, and the information booth at South Station has one like this going out to Back Bay). It's probably telling that, for all that this was done by Boston Globe photographers, there's only one Boston picture in here at all, and none of Amtrak.

Log in to reply
The big picture does trains, finally 07/05/2013 at 11:13 #44392
northroad
Avatar
872 posts
Interesting fact about picture 41 Baikonur is that although you are still in Kazakhstan it is actually rented to Russia. the main east west railway goes through it and you therefore have immigration checks twice. Once when you enter Russia and again when you re enter Kazakhstan........

Geoff

Log in to reply
The big picture does trains, finally 29/05/2013 at 00:56 #45236
maxand
Avatar
1637 posts
SimSig's sims seem so specialized to UK conditions that I would think it unlikely that a US or European sim would find its way into the Downloads, even though the basic principles of absolute block signalling and electronic interlocking would be the same. I imagine many signal symbols would need to be changed, Up/Down orientation of main lines would be different, and allowances made for speed signalling vs route signalling.

Could these obstacles be overcome?

Thanks for the nice pics.

Last edited: 29/05/2013 at 08:12 by maxand
Log in to reply
The big picture does trains, finally 29/05/2013 at 01:26 #45237
BarryM
Avatar
2158 posts
" said:
SimSig's sims seem so specialized to UK conditions that I would think it unlikely that a US or European sim would find its way into the Downloads, even though the basic principles of absolute block signalling and electronic interlocking would be the same. I imagine many signal symbols would need to be changed, Up/Down orientation of main lines would be different, and allowances made for speed signalling vs route signalling.

Could these obstacles be overcome?
Sydney, New South Wales could be done as it is all based on Route Signalling.

Barry

Barry, Sydney, New South Wales, Australia
Log in to reply
The big picture does trains, finally 29/05/2013 at 09:35 #45239
kbarber
Avatar
1743 posts
" said:
SimSig's sims seem so specialized to UK conditions that I would think it unlikely that a US or European sim would find its way into the Downloads, even though the basic principles of absolute block signalling and electronic interlocking would be the same. I imagine many signal symbols would need to be changed, Up/Down orientation of main lines would be different, and allowances made for speed signalling vs route signalling.

Could these obstacles be overcome?

Thanks for the nice pics.

If I understand it correctly (not always a safe bet )

Any line can be set up so trains run in either direction. Right hand running is a doddle (and happily achieved wherever there's bidirectional signalling). Simsig allows such features as overlaps and flank protection to be programmed into the controls for any given signal; if there's no overlap, the controls for the signal simply won't be extended into the subroutes beyond the following signal - again, it's a doddle (even more so if you avoid swinging overlaps).

Some bits of the core code might need changing so that train speeds are dictated by the signal - I suspect that, at present, the train will pass a signal at the highest speed possible as it slows for a speed-restricted turnout, whereas a less-than-high speed aspect in speed signalling requires that speed to be observed from passing the signal until after the speed-restricted section. But I don't know the detail of how Simsig code works and it might be that this is actually a trivial fix (or even possible within the existing code).

Incidentally this seems to have been replicated in real life - SSI (Solid State Interlocking - the system with that trade name) and its successors, developed for UK conditions, have successfully been sold around the world (including, I believe, to SNCF - no further comment needed)! By contrast, it has proven very difficult to adapt foreign computer-based interlockings to UK conditions: Siemens 'SIMIS' is now working at Bournemouth and Havant but not without significant trauma; the saga of Ansaldo's system in South Manchester won't be easily forgotten; and Bombardier, after struggling for a very long time at Horsham were invited to take up their Ebilock and walk (after which an SSI was fitted up - together with alterations in Three Bridges, which had never been part of the original plan - in about 9 months flat).

If you're prepared to accept 'panel signals' very little change to signal indications is required - danger or clear is quite straightforward. I believe the actual form of signals as shown on screen is easy to alter. As a speed indication will always depend, in some way, on the route selected it seems the only question left is how to make up the various combinations of colours and flashing aspects and link each one to a specific route. Again, I suspect this can be achieved fairly easily in data as soon as the graphics are available.

Some signals or aspects that are unknown in UK practice might need changes in the core code, or simply tie them to the nearest UK equivalent. One of the biggest problems is likely to be the sort of situation where a single signal could read from two or more lines, with different indications for each (I'm thinking particularly of Swiss practice here, although I suspect similar things might have been done in Germany and Austria).

The method of operation would be a bit of an issue - NX working is by no means universal, although it does exist. That might be a compromise that would have to be accepted. (It may also be that it's actually slower to set an NX route than some of the other methods, therefore making a big panel more challenging to work.)

I'm probably wrong in some of what I've said but I'm sure Geoff or Clive can put us right on what's technically possible.

As always the issue will be getting the information - detailed plans/maps showing signals from which distances can be derived, details of track circuit lengths, what aspects each signal can actually display for each possible route and so on. I fear those will be far more difficult than the limitations of the Simsig code.

Log in to reply
The following user said thank you: maxand
The big picture does trains, finally 29/05/2013 at 09:49 #45241
maxand
Avatar
1637 posts
Great response, thanks Keith.

Seems like writing a manual to accompany such a sim would be a big job as it would need a whole new introduction to that country's signalling codes!

...One Metro sim coming up...(draws deep breath)

Last edited: 29/05/2013 at 09:52 by maxand
Log in to reply
The big picture does trains, finally 29/05/2013 at 09:51 #45242
Steamer
Avatar
3985 posts
" said:

Some bits of the core code might need changing so that train speeds are dictated by the signal - I suspect that, at present, the train will pass a signal at the highest speed possible as it slows for a speed-restricted turnout, whereas a less-than-high speed aspect in speed signalling requires that speed to be observed from passing the signal until after the speed-restricted section. But I don't know the detail of how Simsig code works and it might be that this is actually a trivial fix (or even possible within the existing code).
From observation of the F2 list, trains passing a yellow will slow to 40 and maintain that speed until the braking point for the signal ahead, or if the 'driver' can see that the signal ahead has changed to a green.

"Don't stress/ relax/ let life roll off your backs./ Except for death and paying taxes/ everything in life.../ is only for now." (Avenue Q)
Last edited: 29/05/2013 at 09:52 by Steamer
Log in to reply
The big picture does trains, finally 29/05/2013 at 10:33 #45243
dmaze
Avatar
88 posts
" said:
From observation of the F2 list, trains passing a yellow will slow to 40 and maintain that speed until the braking point for the signal ahead, or if the 'driver' can see that the signal ahead has changed to a green.
From what I can tell, the mechanics of US operation aren't actually that different from the UK's: instead of seeing a green signal and a "40" sign on the ground, a US engineer sees a red-flashing green-red signal, but in both cases the driver/engineer knows that they can pass this signal at 40 mph through the points/switches and there are two clear blocks beyond the signal. If there is only one clear block, the signal will show red-yellow-red, which is the same thing that would be shown with a 30 mph turnout, but US practice also seems to be that approach signals imply a 30 mph speed limit, which is more restrictive than the allowed turnout speed.

The other minor complication with a "US SimSig platform" is that the signal aspects aren't universal. Is red-over-yellow on a two-head signal "medium approach", with a 30 mph speed limit and implying the next signal is red, or "restricting", allowing the driver to pass the signal but potentially implying the block is occupied? Much of the US uses a single flashing yellow light to mean "advance approach" (exactly the second signal is red) but where I live it is yellow-over-green, the same as "approach medium", in both cases implying a need to slow to 30 mph but making it ambiguous until you get to the next signal which way you're going.

The real problem is going to be getting the very detailed data SimSig requires. It sounds like this isn't easy in the UK, where SimSiggers report visiting working signal boxes with some frequency. Here even taking pictures of trains and rail infrastructure makes local police suspect you of evil intent; if foreigners started trying to gather very detailed information on the safety infrastructure of the Northeast Corridor it probably would not end well.

Log in to reply
The big picture does trains, finally 29/05/2013 at 11:00 #45244
Firefly
Avatar
521 posts
Quote:
The other minor complication with a "US SimSig platform" is that the signal aspects aren't universal. Is red-over-yellow on a two-head signal "medium approach", with a 30 mph speed limit and implying the next signal is red, or "restricting", allowing the driver to pass the signal but potentially implying the block is occupied? Much of the US uses a single flashing yellow light to mean "advance approach" (exactly the second signal is red) but where I live it is yellow-over-green, the same as "approach medium", in both cases implying a need to slow to 30 mph but making it ambiguous until you get to the next signal which way you're going.
This probably doesn't matter, what the signals look like on the ground is largely irrelevant, the important question is what do they look like on the workstation display screen?

Log in to reply