signals by lift bridge

[jytte]

Hello All,

I use a lift bridge in my layout (bendorsey made a great many of them). They're nifty. They are default "up", and automatically goes down when a train approaches.
That's great. But, I needed to have a signal ahead of the bridge. And when I put a signal in, it will be "always green", since the bridge track is an invisible track "always open". Having a signal sitting there showing green, when the bridge is "up" bothered me exceedingly.

After some great advice in different threads, I started experimenting with invisible junctions and miscellaneous rules in the session script. Wasn't quite what I was looking for.

I finally ended up with this simple solution below. I'm sure someone else has invented this wheel before me, but I thought I'd share it with any newbies anyhow, given the struggle I had figuring this out.

I find the point at which the train will trigger the bridge to go down, this is where I place a trigger (trigger xx) on the track, then a signal (signal xx) ahead of it, and another trigger (trigger xx end) just behind the signal.

Same procedure at the other end of the bridge, for the track heading in the opposite direction. All signals and triggers have to be named (I name them for the direction of the track).

this is how that looks in surveyor: (I just added the signs for this 'show and tell')

then in session rules, I add two "set signal" rules (one for each signal)

I set each signal to "danger", this will cause the signals to show default "always red", which is as it should be as the bridge is default "up"

I then add a "trigger check" with underlying "set signal rule" for each of the triggers:

First trigger check (this one south):

and the underlying (indented) set signal, setting the signal to automatic.
This will cause the signal to turn green when the train approaches the bridge and hits the trigger

next in line is the south END trigger

and the signal rule for that sets the signal back to "danger"

Same procedure for the two northbound triggers.

When I go into driver now, I have...

a signal ahead of the bridge (in either direction) that shows red when the bridge is up and no train is nearby

and a signal that shows green when a train is approaching

And this is how it should be.

Hope this might help somebody. At least I'm a happy camper now.


PS: This only works for a 2-track bridge. Since the trigger is not directional, it will react to trains coming from either direction.

 

[ish6]

Great illustration there Jytte ... thanks!!

I'm sure people will benefit from it ....

Good One!!!

Ishie

 

[JCitron]

That's a great idea, Jytte. I experimented with the invisible junctions, but never took this to the next level. I think I'll implement this on my double-tracked sections that use some lift bridges.

Maybe 2009/x will support signalling differently then the previous versions of Trainz so we can implement a simple solution for lift briges and similar objects.

John

 

[jytte]

Thanks both!

Yes, more signal support in 2009 would be great (including diamond crossings!). When we have all these awesome bridges, it's a shame not to signal them, it adds to the realism.

 

[ish6]

Hey,

Perhaps you may have it in your files, but download Vulcan excellent lift bridge as well!!

Cheers,
Ishie

 

[Midland]

That's a wonderful bit of lateral thinking jytte but I can't help feeling the real answer to this question lies with the bridge creator.

Why?

Well you're quite correct about the signal being at red when the bridge is open and that it only goes to green or yellow once the bridge is down.

But look at your tenth picture.

You have a green light but the bridge is still up. I'm quite certain the interlocking and operating system would require the bridge to descend and be locked before the light could go green. This means you need to work on the other side of the bridge trigger which would cut your distance down too much.

Either the creator needs to include the signal set up in his mesh and script or the trigger radius needs to be extended out far enough for all the sequence of events to happen long before the train reaches the bridge.

And again this only works for double track bridges.

You have raised a very important issue here and I hope that some of our bridge builders and scripters look in on this thread to see what they might be able to do. A single track bridge that can work in this way would be fantastic.






Cheers

Nix

 

[jytte]

Hi Nix,

Nice way of passing the buck to the bridge creator :hehe:. Unfortunately I haven't the patience to wait for that to happen.

Yes it would be great to have the bridges themselves support or control a signal. I don't know enough about this to know if Trainz at the moment even could support that, given it won't even support diamond crossings (hmpf), but maybe we can hope for some of this in 2009

Yea, I know the light is green while the bridge is still up (getting demanding now, aren't you?) but I just imagine that the operator of the bridge already has his hand on the controls for the bridge and thus have given the signal to the trains that it is now safe to proceed. As you said between the trigger radius and the radius of the bridge sensor, I can't really get around that because the train would get too close to the bridge, or I would have to stretch my signaling further, which I do not have room for at my present layout. But at least I have a signal that shows the state of affairs in a reasonable manner.

I actually started out with a 2-way single track bridge, but changed it to a 2-track, partly because of this issue, partly because it actually served the layout better. But boy, do we need some directional triggers, for this and other purposes. Signaling and other things are sometimes quite the puzzle when working on single tracks with 2-way traffic.

Rather than having to explain to an "end user" that you can only go in this or that direction on this particular stretch (and they're gonna do whatever they want anyway), it seems practical to make sure your tracks can be safely driven on in any direction.

Hello again Ish, rest asured I have just about everything that vulcan ever created on my computer. Amazing stuff!

 

[seeseeme]

That's very interesting and may help in a layout I and Noel (nbrettoner) are working on. Although our first problem is solved this may help us further.

Our problem was to have a bridge open when a boat approached and stop a train from proceeding.

Many thanks,

Craig

 

[jytte]

It shouldn't be too difficult to place a trigger on your shiptrack, to set the signal to "stop", maybe in combination with the other rules, that should work.

I also believe there is a bridge somewhere that has a track beneath it for just that purpose. I know I've seen it, believe I even downloaded it, but since my re-install I've lost it, and I've been unable to find it again. Maybe somebody else knows where this might be found?

 

[seeseeme]

It shouldn't be too difficult to place a trigger on your shiptrack, to set the signal to "stop", maybe in combination with the other rules, that should work.

I also believe there is a bridge somewhere that has a track beneath it for just that purpose. I know I've seen it, believe I even downloaded it, but since my re-install I've lost it, and I've been unable to find it again. Maybe somebody else knows where this might be found?

You may be talking about our Bridge that Ben made for us. From memory it was Smileyman that worked out what was needed and some changes where made. The bridge I am talking about is on the DLS and called "Tocumwal x" ..... the bridge has a number of variations and thats what the x refers to.

Part of our way of think is that "why is the bridge up", to allow a ship/boat to pass under. If there is no ship/boat then the bridge should always be down. We had to use triggers and a rule (off hand I can not remember which one) in a similar but quite different way to you.

As I said though, you idea may help us more and that is why I am keeping an "eye" on this thread.

Many thanks for your explanation and thoughts on this, its all a great way to view the use of Triggers.

Craig

 

[jytte]

Thanks Craig, I'll have a look for that bridge.

Mind you, this with rules and signals gets rather interesting when there's more than one around. Without thinking about the ramifications on signals, I built a little area in front of aforementioned bridge, which has a station w triple tracks diverging and converging in different directions, and 2 diamond crossings, all of it in a radius of a few hundred meters. It's a puzzle to signal, but I'm almost done, except for one signal that insists on being yellow when it's supposed to be green.
Being that it's such a small area, the signals are close, and multiple signals for various stuff in line one after the other. Now I know what's what, but I can just imagine the poor soul, that gets to drive this one for the first time, no matter what the signals show, he/she is gonna have to stop to figure out what goes where and which switches to pull

Well, maybe that's just because I'm not so familiar with driving with signals, so it's beginning to look like a jungle to me.

 

[nbrettoner]

That's a wonderful bit of lateral thinking jytte but I can't help feeling the real answer to this question lies with the bridge creator.

Either the creator needs to include the signal set up in his mesh and script or the trigger radius needs to be extended out far enough for all the sequence of events to happen long before the train reaches the bridge.

And again this only works for double track bridges.

You have raised a very important issue here and I hope that some of our bridge builders and scripters look in on this thread to see what they might be able to do. A single track bridge that can work in this way would be fantastic.

Cheers

Nix

Hi jytte, Midland & interested parties,

To achieve this result with a 'single' bridge, would it be possible to utilise an 'unused' secondary invisible track?.

Craig (Seeseeme) & I have Ben Dorsey's Tocumwal bridge, for our Narrandera_Tocumwal route (thank you Ben for kindly making this for us! ).
However this bridge will have not only a single rail crossing, but also has road traffic sharing this centre-section raising bridge, as well as river traffic. And the river traffic may require two or three different heights of invisible track, & points!.
We may need to stop all traffic, except one type (of three), & allow only one type, in one direction only.
And this bridge's default position must be 'down'.
And approaching trains must have precedence over river traffic.

Any hands up to have a go at figuring this lot out?. :'sleep::Y::clap:
Help!!!!!

 

[ish6]

Hello All,

I've read this whole thread and it's one of must informative I come across in a while ...

Thanks all
Ishie

 

[bendorsey]

Hi Guys:

Great work (I know nada about AI and signaling).

I've made several bridges that are normally closed and open at the approach of a boat which has been configured as a loco running on invisible track in the water. They will stop auto-traffic if a car bridge and can be made to stop train traffic too. I don't remember off hand which ones or how many but most have a readme file in the folder explaining how to set them up if they are train bridges.

All have the same shortcoming. The trigger distance is fixed (around 80 meters I think). Hopefully in TRS2009 it will be user adjustable (hint hint hint).

Ben

 

[jytte]

Hello Ben,

Since you dropped in, I take the opportunity to thank you for all the great bridges you've made:wave:

Since I discovered triggers, they don't give me signal problems anymore, and they add a lot to a layout!

 

[ish6]

Hi Jytte

Nice site you got there ... :wave:

Ish

 

[stagecoach]

That's very interesting and may help in a layout I and Noel (nbrettoner) are working on. Although our first problem is solved this may help us further.

Our problem was to have a bridge open when a boat approached and stop a train from proceeding.

Many thanks,

Craig

Craig
Sometime ago i did this for someone and it is very simple. Use the trigger muliple signals rule. Place triggers along the ship track from a point before the ship triggers the bridge to a point after the ship leaves the bridge trigger radius(number of triggers will vary). This allows the signals to go red before the bridge opens and green after it shuts. Name the triggers and the signals on the rail track and set it up in the rule

 

[jytte]

Thanks Ish,

Hello Craig,

The "trigger multiple" works for only 1 trigger at a time though. I find it easier to use 1 "trigger check" (which will detect multiple triggers) and then "set signal" for one or more signals below that. Guess It depends on the situation you're trying to signal for.

The trigger check/set signal combination works wonders for me where the "multiple signal" and the "diamond crossing" fall short. Just solved my dual track crossing with that, along with my bridge.

 

[stagecoach]

trigger multiple signals works on more than one trigger.

 

[jytte]

Thanks Stagecoach

My mistake, I just went and tried it again, and it does pick up multiple triggers as well,
That's cool, now I can streamline my rules even further.
Do you happen to know if one can use multiple "trigger multiple" rules without problems?