YAPP vs Pre-Signals

[Treso]

Hey, I visit these forums as guest for a long time and just know I created an account. I know OpenTTD since version 0.4 and I really loved when I found this project.

But I have some question to ask:


I really used Pre-Signals for a long time and in few days I start to download nightlies and build YAPP signals. It will be the "signals of the future"?
What the OpenTTD veterans uses currently?
Where can I find more complex (advanced) junction and networks than the ones find at the wiki?

Sorry for my bad english.

Thanks.

[CommanderZ]

There are no really well tested PBS junctions atm imo. OpenTTDCoop played one of their lastest games with YAPP, so you may try to look at it. Also, there were always plenty of beautiful junctions in their games, so just download any of their saves, watch and learn

[Alberth]

I really used Pre-Signals for a long time and in few days I start to download nightlies and build YAPP signals. It will be the "signals of the future"?

I don't think the 'old' signals will disappear. See it more like you got a new set of toys to play and experiment with, and do things otherwise not possible (in the space you've got).

What the OpenTTD veterans uses currently?

Everybody is trying them (the big shift will come when a release is made with YAPP in it, many people only play releases), many will like them, some will not. You'll see new ideas and junctions popping up as time passes by.

Personally, I don't find this a very interesting question. I think everybody should play the game in the way he/she likes. OpenTTD gives you that room, luckily.

Sorry for my bad english.

No need to excuse yourself, many people (including myself) do not write or speak English natively. As long as try writing good sentences, the occasional mistake is easily forgiven.

[Lordmwa]

Sorry for my bad english.

No need to excuse yourself, many people (including myself) do not write or speak English natively. As long as try writing good sentences, the occasional mistake is easily forgiven.

Like this one

Back on Topic, I have used Pre-Signals for the last 2 years and i hope i used them about as effectivly as possible. The best thing about pbs (not yapp) is that it allows trains to find alternative routes. In a station entrance you can make all of the leads into a station 2 way allowing trains to go wherever they can. Also i have found since using PBS (may be pathfinder realted however) that trains choose through platforms if they are going through and not bay platforms. Pre-signals just say if there is a free platform use it. PBS says waiting for free path untill a route allowing the train into a signal block while still reaching the final destination.

Lordmwa

[Eddi]

i completely switched to YAPP the instant it came out. PBS signals are far superiour to presignals.

• junctions tend to be much more compact
• single tracks with sidings can be used more efficiently
• platforms are accessible from both sides without blocking by race-conditions
• this station is impossible to do correctly with presignals (believe me, i have tried)

[Tekky]

junctions tend to be much more compact

Not only more compact, but also more efficient.

[Youri219]

junctions tend to be much more compact

Not only more compact, but also more efficient.

They're only more efficient if you do make them compact. For any real efficient junction you simply need non-equal level crossings, such as bridges or tunnels. I could even argue that for real large junctions the old fashioned normal signals are the most efficient, since trains don't have to reserve long pieces of track but stay at a 2-tile distance the entire time.

Anyway, this brings up a really interesting question, are there any good designs for major junctions using YAPP already? My best guess would be multi-lane roundabouts, with several bypass lanes, and some mergers behind it.

[Octopuss]

I don't even understand presignals yet, so this is all confusing to me. I understand this YAPP is some kind of pathing system for vehicles, but what's the difference? There are new kind of signals we can build under this new system or what? Will the signals menu cover half the screen now?:D
Also what does PBS stand for?
totally confusing...

[DJ Nekkid]

there are two YAPx's ...
YAPF - yet another path finder
YAPP - yet another pbs patch (or project?)

YAPF is the pathfinder, YAPP is a PBS-extension to that.
and then it comes to PBS. PBS = Path based signaling. To hopefully explain it easy. You have a station with lanes going in and out in the same direction (for example from the east).
in on a. out on b.
With YAPP or "advanced signals" as it say in game, a train can come from a, going thru the junction into station-a, when at the same time, a train goes from stationb into track B

a---\/-Station-a
b---/\-Station-b

[Octopuss]

Doesn't make it much clearer unfortunately
Does it work so that you don't need any other than basic signals as the pathfinding code is so good?

[Brianetta]

Doesn't make it much clearer unfortunately
Does it work so that you don't need any other than basic signals as the pathfinding code is so good?

It doesn't do the work for you.

OK, let's try to explain it from the perspective of a beginner.

Block signals is a good term for grouping together all the signals that aren't PBS. That is, all the traditional signals and pre signals and so on. These signals are used to stop trains colliding with each other. They achieve this by separating your track into signal blocks. One signal block is any continuously connected track, including junctions, extending in all directions until a signal is met. The signal itself marks the boundary between signal blocks. Signals protect a block by refusing to allow more than one train into a block at a time. If the block is empty, they show a clear signal (flag up, or green aspect). If the block is occupied, they show a danger signal (flag down, or red aspect). Trains stop at danger signals.

These are available in two-way or one-way versions. The difference is only that trains can't cross a one way signal from behind.

A pre-signal shows clear if the block it is protecting is unoccupied, unless that block has exit signals: If there are exit signals, and none of them are clear, then the pre signal shows danger. This stops trains entering a block if there's no way out, which keeps that block clear for other trains. Applications of this are left up to the player; it's most commonly seen at stations, where trains have to be able to get out to let others in.

Path based signals are technically new in OpenTTD, although they've been here before in another form, and TTDPatch has had them for a while. They act differently from block signals, in that they will allow more than one train to enter a signal block if they're definitely not going to collide. On a straight bit of track, this means they act pretty much like block signals. If there's a complicated patch of track (two ways in, two ways out, for example) and two trains won't use the same bit of track, they'll show clear and let them both through at the same time.

[Rainer]

Hi Brianetta,

your text would be a great! improvement as introduction to the wiki article about signals.

cu
Rainer

[ostlandr]

Absolutely. I only use the standard PBS signal, except for those rare locations where I need a one-way PBS signal to make sure trains only travel one way through a junction.

The attached shows my basic station design with both regular presignals and PBS. These are set up for max 4 tile long trains.

Pritchard North has an entrance presignal on the inbound track at each end of the platform, and exit presignals at each end of the station platforms. An inbound train will wait at the entrance presignal until an exit presignal is green (indicating a free station platform.)
Works okay with low volumes, but there are two problems. First, only one train can occupy the X crossover blocks at a time. This makes each of those crossovers a single-track bottleneck. Second, a train leaving the platform will stop at the signal guarding the outbound main (if red), tying up the crossover block and one station platform.

Pritchard Woods has standard PBS signals. Trains moving in opposite directions will share the X crossovers so long as their movements don't conflict (like in a real-world interlocking.) Trains won't leave the station platforms (which have PBS signals facing out- this is important) until there is a clear path to the next PBS signal. Notice I left four tiles empty before the next signal on the outbound track- this is also important. Never place a PBS signal where a train stopped in front of it will obstruct another junction, platform, etc. Also, standard PBS signals aren't one-way- if a train can't find a path going the "right" way, it will take the "wrong" track, reserving a path until it hits the front of a PBS signal. If you don't want trains tying up an entire main like this, use a one-way PBS signal, or add another X junction where the train can get back on the right track. I can almost hear the dispatcher, "Train 28, be advised train 16 is disabled. Proceed eastbound on the westbound main until Pritchard NW crossover, retake the eastbound main, and hold short of Johnsonburg Woods."

Strangely enough, this also makes single track railroading practical (if not a game winning strategy.) A train will wait until it has a path to a safe waiting location (which the pathfinder assumes is in front of a PBS signal) before entering a stretch of single track. So as long as you have two-platform stations (or one platform with a run-around track) and possibly passing sidings, you can do old-time single track railroading.

Doesn't make it much clearer unfortunately
Does it work so that you don't need any other than basic signals as the pathfinding code is so good?

[Brianetta]

Hi Brianetta,

your text would be a great! improvement as introduction to the wiki article about signals.

cu
Rainer

Rainer, if you saw a spot on the wiki where it would fit, do feel free to paste it in there.

Strangely enough, this also makes single track railroading practical (if not a game winning strategy.) A train will wait until it has a path to a safe waiting location (which the pathfinder assumes is in front of a PBS signal) before entering a stretch of single track. So as long as you have two-platform stations (or one platform with a run-around track) and possibly passing sidings, you can do old-time single track railroading.

Can't say I ever had a problem with old-time single track railroading. It's my preferred rail type, as players on my (non-PBS) server will attest. (:

[frankh]

Hi,

i'm not sure if to switch to YAPP. My problem is, that i heavily used priorities until now. (e.g. on the exit of ml-depots or when merging a ml with a sl). Is that possible with YAPP? Or is it no longer necessary? Or is there a good way to use priorities with "old" signals together with the concepts described in http://wiki.openttd.org/index.php/YAPP_ ... (advanced)?

Frank

[Treso]

Im trying to use YAPP but I just didnt understand one concept yet.

What is best. Use a two-way double track or 2-2 one handed tracks?

Thanks.

[Brianetta]

frankh, I'd not describe any of those layouts as particularly advanced, just over-complicated. The huge advantage of path based signals is that you can simplify your track work without causing extra congestion.

Treso, do you understand the basic concepts of signalling as I described earlier in this thread? click here to scroll back up to it. If you do understand that, then you're well on the way. Using path based signals, the idea is to place a signal at any point where you don't mind a train waiting if it cannot safely proceed. I'm not entirely certain what you mean by "two-way double track or 2-2 one handed tracks" but if you plan to use PBS crossovers, use them infrequently. If your mainline track has as many crossovers as signals, your trains will dance around each other and get in each others' way. That wiki article is a prime example of how not to do it.

[ostlandr]

How much traffic do you have? I start with single track and passing sidings, then upgrade as needed to double track (with PBS, it can be used in either direction.)
Then if necessary I upgrade to a 3 track main, with the center track blocks having inward-facing signals similar to station platforms, so it only gets used as a passing track when the main is tied up.
From there I upgrade to 4 tracks- at this point I usually use waypoints to sort trains by speed, putting passenger trains and possibly "time freights" on separate tracks.
Beyond four, I tend to break the line up into "lanes" going to specific destinations- separating local and "through" traffic.

Here's a couple articles that might help you understand the concept:

http://en.wikipedia.org/wiki/Direct_traffic_control

http://en.wikipedia.org/wiki/Interlocking

I find that the PBS system works similar to a DTC system, assigning blocks to specific trains when the movement won't conflict with another train. And at junctions, it functions much like an interlocking tower.

Im trying to use YAPP but I just didnt understand one concept yet.

What is best. Use a two-way double track or 2-2 one handed tracks?

Thanks.

[Aphfaneire]

Sorry for my bad english.

No need to excuse yourself, many people (including myself) do not write or speak English natively. As long as try writing good sentences, the occasional mistake is easily forgiven.

Like this one

Back on Topic, I have used Pre-Signals for the last 2 years and i hope i used them about as effectivly as possible. The best thing about pbs (not yapp) is that it allows trains to find alternative routes. In a station entrance you can make all of the leads into a station 2 way allowing trains to go wherever they can. Also i have found since using PBS (may be pathfinder realted however) that trains choose through platforms if they are going through and not bay platforms. Pre-signals just say if there is a free platform use it. PBS says waiting for free path untill a route allowing the train into a signal block while still reaching the final destination.

Lordmwa

I have witnessed the opposite!

On one map i built i had bay's that my trains would use if the smaller through platforms were blocked. they would then sit for ages untill they could turn and go through the platform they were meant to.

Its a mother to fix but if you make the through trains electric it negates the problem