The International Simutrans Forum

Ok.
Here is an explanation in simple english :)

In Simutrans, route reservation is from stop - signal, stop-stop, signal-stop, signal-signal.

Normal Signals, rail signals work like so:

Train comes up to normal signal. Waits there until it can reserve a route to it's next stop.
However, if there is another signal on the route , then it waits to reserve the section between signal A and signal B.

Pre Signals

Train comes up to pre signal block A. Presignal holds train there until block B(the Block next to it) is free, and Signal C (The next signal) is free.

(Train A waits here)A--B-------------Train B is occupying this area------C

Therefore, Train A is waiting for block B to be freed, and Train B to go past Signal C.

Long-Block Signals

If you have 1 track with several stations, and 2 entries at each side, place a long signal at the entries. Therefore, the train will only go past the signal if the entire section of track up to the other long signal at the other side if there isn't a train in the section of track between the Long Block Signals.

                          =                                                                                                        =
                          =                                                                                                        =      
=Train waits here(->)==LBSignal======Station=<---Train is going this way==Station========LBSignal===

Platform Choose signals

If you have a station with multiple platforms, place at the entries BEFORE the junction. The train will then reserve the platform.

End of choose signals stop the platform choose area.

If I'm wrong about any of this, please correct :)

Ummm... okay. I know for signals and pre-signs.

So, I will post some pictures (SimuTrans) to show whether I'm correct or wrong.

Signals:
                                  ===========[Station][Station]============
[T]->======[Si]======"===========[Station][Station]==========="======[Si]=========<-[T]

Key:
[T] Train
[Si] Signal

Is is correct to place like this?

Ok, what you've got here is this: 2 trains are attempting to go into a Station from different ends, going towards each other. What is needed here is a Platform Choose signal, and a long block signal.


                                     =[LSi]==========[Station][Station]=========[LSi]=
[T]->======[Si]====[PSi]=[LSi]=========[Station][Station]==========[LSi]="[PSi]=========<-[T]

Could you re upload - use tiny pic

<obsolete>

</obsolete>

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Another small observation :

If you place a long block signal after a standard signal and have a train X running between the 2 signals, when another train Y arrives at the standard signal, the standard signal cannot block this second train from proceeding as it usually does.

+++++++Y+S++++++X+++++++L++++++++++++>>

---

EDIT 1 : Below and green words above

Having said so much about long block signal, I think I must also digress a little bit to talk about the behaviour of a choose signal for railway, as there is something similar between it and a long block signal.

It is important to understand the mechanics of a choose signal :

1) In essence, it actually does not work with the next upcoming station ahead on the track. Rather, it works with the next stop on the schedule of the p****ing train (waypoint also counts as a stop). This aspect is similar to the long block signal.

2) It not only lets the train choose from the available platforms in the next stop, the choice of platform will also be made immediately and the portion of track from the choose signal up to and including the chosen platform will be reserved. If such track reservation cannot be made successfully due to the presence of another train in that track section, the train will wait at the choose signal until that portion of track is clear.

3) Any intervening standard signal between it and the next stop on the train schedule cannot stop or cut short the portion of track reserved.

Usually, when we use a choose signal, we will place it before a station with multiple platforms so that incoming trains can choose from among them. If all trains p****ing through the choose signal also have that multi-platform station on their schedule, there should not be any problem.

However, as we continue to expand our railway networks, very often we will reuse existing railways. New trains are introduced but they may not be scheduled to stop at all stations along the way. If they drive past a choose signal but do not have the upcoming station on schedule, they may reserve a really long portion of track from the choose signal all the way up to and including the next stop's chosen platform.

To illustrate, let's ****ume the following set-up :

++++++++C+X+S++++++++++S+++++++Y++++++++S++++++++++++++++Z++++++++++>>


A train is driving into this track section from left to right. The train only has Z on its schedule. X is a multi-platform station and thus a choose signal C is placed in front of it.

When the train drives past C, it will look ahead and choose from any available platform from Z. If it has found and chosen an available platform of Z, the train will try to reserve the portion of track from the choose signal up to and including the chosen platform of Z.

If such track reservation is successful, it will proceed forward. If such reservation is unsuccessful due to presence of another train or simply because there is no unoccupied platform at Z to select at the moment, the train will stop and wait at the choose signal. Note that any intervening standard signal has no effect on such potentially aggressive reservation of lengthy track section. Needless to say, reserving long portion of track will increase the likeliness of deadlocks as well as the waiting time of a train.

So, once again, the behaviour of a choose signal depends on the individual schedules of the p****ing trains. One has to be careful in planning where to set up a choose signal, especially if the track portion is shared by more than one railway line.

Edit 2 : Obsolete section above regarding Long Block Signal

That's from the link I posted earlier, ask me if you don't understand anything and I'll try to explain it to you. It clearly explains the mechanics of the choose signals and long-block signals. I think it's very handy! Everything seems to be covered.

As for your picture it will not work, I really can't be bothered explaining why at the moment but I'll tell you a solution.
    
                     ==============[>]                                     [<]====================
=============[<]=======================[STATION]====================[>]========================

The < and > indicate long-block signals allowing travel in the indicated direction. (Click again to change direction from 2ways to 1 way in either direction)
This will make trains wait at the long block signal until the track up to the next signal  is clear. That means they wait on that double track until the station is clear and the part after the station. This kind of layout is efficient for about 3-4 trains (2-3 in this section but more on other side might be fine) but it all depends on how long that double tracking is. But if you insist on making the waiting bay (double tracking) really long then you'll have constant jams.

If you have any questions don't be afraid to ask.

EDIT: I was looking at your picture wrongly, on second thought it would work with the station being able to handle 2 trains at once but with a maximum of 3 trains. Having 4 trains will cause much confusion with trains coming from both direction. Also, handling 3 trains can cause a deadlock. Suppose 2 trains just left the platform and are heading towards the left where another train is waiting at the choose signals. The 2 trains that just left will get stuck on the Long-Block signals with nowhere to go. Therefore it can only handle 2 trains efficiently unless you have trains going in only 1 direction. And if you only have 2 trains then 2 platforms is just wasting your money.

Mine will only jam up if you have jams further down the track. Those jams will cause a train that just left the platform and is waiting at either signal to be stuck there. But mine can still be slow if you have slow trains that enter and leave the platform slowly (or take a long time at the platform) which will cause the waiting to train to keep waiting until the slow train is clear.

You'll learn! I'm only 14 myself. Now I will have to say right off that that isn't a very efficient station. Remember that station maintenance costs are expensive! Now 3 platform stations must be very busy! But since I can see you have 3 single tracks running off means that you can't possibly have many trains (single as opposed to double which are 2 lines that run side by side usually with 1 going in each direction). The best way I can see (remember I'm still pretty much an amateur myself) is to build a "Loop" Station as I call it. Which is just a one-way station. Trains enter one side and leave the other.

>>>>>>>>>>[Station]>>>>>>>>>>
^^                                        VV
<<<[Signal]<<<<<<<<<<<<<<<<=======================

In this diagram trains enter from the right and go to the left where they queue up waiting for the station to clear up at the signal. Then they go through to the station and out the other side back onto their line. This is a pretty simple station, no complex signalling required and it can handle many trains. The trains just queue up at the signal and since there is only 1 direction of travel there isn't any chance of jamming.

You can build a multi-platform station in this style by adding another platform parallel to the current one and changing the signal into a choose signal.

Now to implement it in your situation I would delete the topmost platform.

Ok, thanks but I added a new station. Sigh.

I got another one. Am I correct on this picture below?


PS: The trains in each rail can go in either directions.

Great, it is not working! 

How to fix that?

Triple posting...

Use long block signals, not pre signals.

I'm waiting for the answer. I have problems with the routing!

no no, take another picture, then uplload to www.tinypic.com