Upcoming Games


Full list
Add a game

Upcoming Events

Who's Online

headshot119, gazman321, GeoffM, Soton_Speed, kaiwhara (5 users seen recently)

Various questions

You are here: Home > Forum > Simulations > Released > King's Cross > Various questions

Page 1 of 1

Various questions 29/03/2022 at 20:27 #145920
Dionysusnu
Avatar
472 posts
I was looking at some pictures from King's Cross PSB in 2008, and these raised the following questions:
- Should S317 be approach controlled from red? There is the following picture showing it as off, while no train has passed 313 yet: https://photos.signalling.org/picture?/20424/category/2138-2008_july . The speed reduction was 65 to 45 in the 2006 SA, maybe this route was flashing yellow?
- Should S384 be unrestricted towards Drayton Park? The speed reduction is 35/55 to 30. The following pictures all show a route set, and the conditions seemingly met, but 384 still at danger: https://photos.signalling.org/picture?/20435/category/2138-2008_july
https://photos.signalling.org/picture?/20436/category/2138-2008_july
https://photos.signalling.org/picture?/20437/category/2138-2008_july
- Should S101 and S102 have opposite locking? The following picture seems to show them both set and cleared at once: https://photos.signalling.org/picture?/20446/category/2138-2008_july
- Should S193 have a headshunt subsidiary route? The following picture seems to show something of the sort: https://photos.signalling.org/picture?/20454/category/2138-2008_july
- Should S474 have an auto button? The following picture shows it not having one, although it may have been added/removed at some point: https://photos.signalling.org/picture?/20455/category/2138-2008_july

Log in to reply
Various questions 29/03/2022 at 20:48 #145921
postal
Avatar
4869 posts
Presumably you are asking for your own personal interest as GeoffM has already stated a number of times that the sim will not receive any further updates.
“In life, there is always someone out there, who won’t like you, for whatever reason, don’t let the insecurities in their lives affect yours.” – Rashida Rowe
Log in to reply
The following users said thank you: Meld, Hap
Various questions 29/03/2022 at 21:02 #145922
Dionysusnu
Avatar
472 posts
postal in post 145921 said:
Presumably you are asking for your own personal interest as GeoffM has already stated a number of times that the sim will not receive any further updates.
For curiosity, and to know whether the existing, now as you say unsupported, simulation is accurate regardless.

Log in to reply
Various questions 29/03/2022 at 22:12 #145930
clive
Avatar
2545 posts
K384 to Drayton Park is definitely approach controlled; I remember watching it many a time when I had to visit the office near Old Street. I think that it stays on until the approaching train has passed the tripcock tester half way down the platform, though that's probably a timer on the track circuit rather than anything more complicated.

K360 is held at red until the platform is occupied and no current is being drawn from the catenary. The class 313s and 717s have a bleed resistor on the pan so that they are always drawing current; that's the source of the buzzing noise you can hear.

I have one undated scheme plan that shows K474 without an A button. I'd have to check my archives for others.

For the others, it looks like you're right, but see postal's comment.

Log in to reply
The following user said thank you: Dionysusnu
Various questions 30/03/2022 at 07:28 #145933
clive
Avatar
2545 posts
I dug out some scheme plans from about 5 years ago; note that this isn't necessarily the exact same layout as the sim was written for.

K317 to K321 is approach released from yellow. That's something relatively new in UK signalling principles and it might well have been from red in past times.

K384 to Drayton Park is not only approach controlled from red, it requires a successful tripcock test to clear.

K193 does have a headshunt route.

K474 has an A button applying to the straight-ahead route only.

Log in to reply
The following user said thank you: Dionysusnu
Various questions 30/03/2022 at 07:41 #145934
kbarber
Avatar
1621 posts
clive in post 145933 said:
<snip>

K317 to K321 is approach released from yellow. That's something relatively new in UK signalling principles and it might well have been from red in past times.

<snip>

My memory of the exact terminology is a little hazy (I didn't pay enough attention at the time). Is that the same as 'free yellow'? If so, I believe it existed in times past (down slow - down fast route at Tring North comes to mind), and I suspect may be one of those things that was banned then approved again, as needs and perceptions of risk changed.

Last edited: 30/03/2022 at 07:42 by kbarber
Reason: None given

Log in to reply
The following user said thank you: TUT
Various questions 30/03/2022 at 08:14 #145935
Jan
Avatar
829 posts
Yeah, wasn't there something about HSTs and other trains with superior brakes starting braking later and therefore possibly not slowing down enough in the case of approach control from yellow, hence we got flashing yellows as a more distinctive alternative signalling sequence?

(It's possible I might actually remember the above from this page here…)

Two million people attempt to use Birmingham's magnificent rail network every year, with just over a million of them managing to get further than Smethwick.
Log in to reply
Various questions 30/03/2022 at 13:32 #145944
clive
Avatar
2545 posts
Hmm, I'd forgotten some of those details. Flashing yellows came into use somewhere around 1980 (for the reason Jan remembers), so free yellows would have been in the principles before that and would have been available when King's Cross PSB opened in 1976-ish. Though it might have been reserved for special cases when the box opened and it might even have not been available in the geographic interlocking hardware that KX used. But maybe it was free yellow from day 1 (I don't have the relevant information).

I can say that the original KX didn't have any flashing aspects at all. The first ones were added at the exits to Welwyn tunnels (in both directions). Hitchin got them on the down fast-to-slow crossover when it was speeded up to 70 mph; I don't recall if it had any others.

Log in to reply
The following user said thank you: Dionysusnu
Various questions 02/04/2022 at 10:14 #145997
Guts
Avatar
458 posts
I can explain K101 and K102. This is a back to back shunt. This allows repeated shunts from Hornsey Depot into the spur and back, without the signaller having to restroke the route for every move.
This is similar to Neville Hill request for shunting; Wembley Yard (Wembley Mainline Sim) has a similar feature at the north end of the yard from the North Arrv Line into the Shunt neck adjacent to Wembley Central, but I don't think it is simulated. Leeds East/West Sim (containing Neville Hill) came out after Wembley Mainline Sim and had newer features

Log in to reply
Various questions 02/04/2022 at 12:56 #146001
clive
Avatar
2545 posts
In the core code we call this "opposing locking omitted". From memory, the Hitchin area of the KX sim is where this first got tested, so the only reason it wouldn't be implemented at K101/K102 is that we didn't realize it applied.
Log in to reply
The following user said thank you: Dionysusnu
Various questions 02/04/2022 at 17:26 #146003
GeoffM
Avatar
5876 posts
Online
clive in post 146001 said:
In the core code we call this "opposing locking omitted". From memory, the Hitchin area of the KX sim is where this first got tested, so the only reason it wouldn't be implemented at K101/K102 is that we didn't realize it applied.
Not just what we call it: it's what the signalling standards call it, and thus control tables too. Of course, there's bound to be a region where they call it something different.

SimSig Boss
Log in to reply
The following user said thank you: Dionysusnu