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Offline Rinus  
#1 Posted : 13 January 2021 11:10:22(UTC)
Rinus


Joined: 20/02/2005(UTC)
Posts: 1,726
Location: Wageningen, The Netherlands
Hi guys, I would appreciate some help.

I’m to install a different system for track detection. Now I’m using the uhlenbrock lissy system for track detection together with rocrail for automatic train control. The lissy system will sold and replaced by a S88 like system.

For those of you who have experience with this, how long should I make the section for track detection?

Some say one train lenght others say the length of an entire block section and others only 9 cm or so.

My rocrail design currently relies on 3 sensors per block in the visible areas and 2 in the hidden yards. I want to keep it that way if possible to ensure smooth transition.

Regards,

Rinus

Edited by moderator 13 January 2021 23:58:39(UTC)  | Reason: Spelling

Offline French_Fabrice  
#2 Posted : 13 January 2021 12:26:39(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,335
Location: Lyon, France
Hello Rinus,

Just to be sure:
1- You are currently using Lissy system
2- You are going to replace it by S88 like system

Is it correct ?
Cheers

Fabrice
Offline Rinus  
#3 Posted : 13 January 2021 12:27:52(UTC)
Rinus


Joined: 20/02/2005(UTC)
Posts: 1,726
Location: Wageningen, The Netherlands
Originally Posted by: French_Fabrice Go to Quoted Post
Hello Rinus,

Just to be sure:
1- You are currently using Lissy system
2- You are going to replace it by S88 like system

Is it correct ?
Cheers

Fabrice


Yes that is correct!
Offline French_Fabrice  
#4 Posted : 13 January 2021 12:45:34(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,335
Location: Lyon, France
OK,

So please remind: The real concept to master is Block, not track occupation.

For automated trains using blocks, each block needs to have some sensor(s) in it.
As you already use Rocrail, you know about sensors which are associated with Events (like Enter, Pre2In, In events).

Another reminder: to manage blocks, an Event is fired only on the first occurrence of track detection occupation.

A feature introduced in Rocrail since a few years is BBT, which allow smooth deceleration in blocks.
When using BBT, 2 sensors are enough i.e. Sensor associated to Enter event and Sensor associated to In Event.

When a train has to slow down in a block with BBT, the slow down starts when the Enter event is triggered, until VMin is reached, then when In event is fired, the train goes from VMin to 0.
For such behavior, I think 9 cm for Enter sensor zone is enough, and depending on the inertia and CV settings, 18cm or 27cm is enough for In sensor zone.
Of course, this suppose the train has enough room to decelerate (the block is long enough) until reaching In sensor. But this depends also on the incoming speed at Enter sensor...
In case your block is bidirectional, then In and Enter sensor zones should have same length (18 or 27 cm)

A use case with a 3rd sensor (pre2in) in the block is for some station tracks where a "short train" have to stop not at the end of the block (In location) , but at the pre2in zone (close to the station or in the middle of the platform...)

That's a quick answer.
Cheers
Fabrice
Offline Rinus  
#5 Posted : 13 January 2021 13:30:11(UTC)
Rinus


Joined: 20/02/2005(UTC)
Posts: 1,726
Location: Wageningen, The Netherlands
Originally Posted by: French_Fabrice Go to Quoted Post


Another reminder: to manage blocks, an Event is fired only on the first occurrence of track detection occupation.

For such behavior, I think 9 cm for Enter sensor zone is enough, and depending on the inertia and CV settings, 18cm or 27cm is enough for In sensor zone.
Of course, this suppose the train has enough room to decelerate (the block is long enough) until reaching In sensor. But this depends also on the incoming speed at Enter sensor...
In case your block is bidirectional, then In and Enter sensor zones should have same length (18 or 27 cm)


Thx for your reaction! This is helpful.

Question: you say an event is fired only by first occurance of detection. Now would it be possible that in case of a short sensor zone of 9-27 cm that the event fired by the last wheel set of a 30cm coach behind the loco is seen as another train? If so this would make it more logical to me to use a 40cm section lenght as a minimum in order to keep the section activated until the entire train has passed?
Offline French_Fabrice  
#6 Posted : 13 January 2021 13:48:39(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,335
Location: Lyon, France
Frankly, I've not seen such behavior.

Because when 1st time event is fired, the "state" of the block changes.
As a result, the software ignores other same event for Enter sensor related to other axles firing the event.

For "In" sensor (arriving), the additional event for same sensor are also ignored, and for departing from the In zone, the block is freed only when the next block has its zone "In" reached. So, anything related to passing over "In" zone (departure) is ignored whatever the number of axles passing over..

That's a common misconception to think other axles will trigger an other event. In fact it depends on the state of the block.

See https://wiki.rocrail.net/doku.php?id=block-en for block status.

The only thing you have to determine is the right length of the "In" zone, in case it is just before a switch coming from another track. Most of the time, 18 or 27 cm is enough, but the Vmin speed must be low (10 or 15%) of max speed.

Cheers
Fabrice

PS: For sidings tracks, you may wish to add more sensors if you want to trigger special events, some of these additional sensors may not be related to block slow down
thanks 1 user liked this useful post by French_Fabrice
Offline fynrfin  
#7 Posted : 13 January 2021 22:20:48(UTC)
fynrfin

United States   
Joined: 19/01/2005(UTC)
Posts: 71
Location: United States
Originally Posted by: French_Fabrice Go to Quoted Post
OK,

So please remind: The real concept to master is Block, not track occupation.

For automated trains using blocks, each block needs to have some sensor(s) in it.
As you already use Rocrail, you know about sensors which are associated with Events (like Enter, Pre2In, In events).

Another reminder: to manage blocks, an Event is fired only on the first occurrence of track detection occupation.

.....A use case with a 3rd sensor (pre2in) in the block is for some station tracks where a "short train" have to stop not at the end of the block (In location) , but at the pre2in zone (close to the station or in the middle of the platform...)

That's a quick answer.
Cheers
Fabrice

,
Thank you Fabrice,

I hope it is OK to ask a similar question in the same thread. I have some long storage tracks, which may fit two shorter train one after another. I would like sensor tracks to be long in order to catch lost cars, as the tracks are hidden.

So is such long track one block or two blocks?

Can I have just two sensors? one covering the first say 150 cm of track and another covering the next 150 cm?

Right now I had only planned for one long sensor across all 300 cm, but that will not work to park more than one train for the shorter trains, correct?

What would you suggest?

Sincerely,
Steen
Steen Jorgensen
Planning a Northern European (DSB and DB) C-track layout with IB control.
Offline French_Fabrice  
#8 Posted : 14 January 2021 08:19:28(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,335
Location: Lyon, France
Hello Steen,

I'm sorry but I don't know how to answer correctly to this question.
Maybe other forum members have some answers to provide.

However, for automation, the basic rule 1 block = 1 train must still apply. That means if you want to store 2 trains in a very long track, you need 2 blocks.
I think for occupancy detection, a 3rd "long" sensor can be used in addition to 2 short "enter" and "in" sensors, but I don't know how to handle it automatically with Rocrail.

In Rocrail, there is also a concept named "staging blocks" but I doubt it can be used in siding sections with one end "closed".
Cheers

Fabrice
thanks 1 user liked this useful post by French_Fabrice
Offline JohnjeanB  
#9 Posted : 14 January 2021 15:52:18(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 1,326
Location: Paris, France
Hi Steen
Originally Posted by: fynrfin Go to Quoted Post

I hope it is OK to ask a similar question in the same thread. I have some long storage tracks, which may fit two shorter train one after another. I would like sensor tracks to be long in order to catch lost cars, as the tracks are hidden.

So is such long track one block or two blocks?

Can I have just two sensors? one covering the first say 150 cm of track and another covering the next 150 cm?

Right now I had only planned for one long sensor across all 300 cm, but that will not work to park more than one train for the shorter trains, correct?

What would you suggest?

Steen

With Rocrail you have multiple possibilities: one is to have multiple blocks on the same portion of track, the other is to use a "staging block"

Staging block
* allows to have variable length trains stored behind each other in the same block
* it must be a one-direction block
* it can have as many sensors to store each train behind each other very precisely
* you MUST state the length of each train and the length of the security gap you wish in between
Here is a video of a staging block

Cheers
Jean


My layout videos
latest vid
hump yard
thanks 2 users liked this useful post by JohnjeanB
Offline Martti Mäntylä  
#10 Posted : 14 January 2021 22:56:40(UTC)
Martti Mäntylä

Finland   
Joined: 15/11/2018(UTC)
Posts: 218
Location: Uusimaa, Helsinki
This tutorial explains how Rocrail's "virtual blocks" can be used to implement storage tracks for variable length trains.

- Martti M.
Era III analog & digital (Rocrail, CAN Digital Bahn, Gleisbox/MS2, K83/K84), C & M tracks, some Spur 1
thanks 3 users liked this useful post by Martti Mäntylä
Offline JohnjeanB  
#11 Posted : 15 January 2021 11:58:22(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 1,326
Location: Paris, France
Hi Martti

Thanks for the info. I use virtual blocks mostly for assembling a train (cars with loco) or separating a train.
The virtual block would have the train and the slave blocks at extremity would host the loco so that it can come back the seek the cars (the virtual block is occupied while the slave block is free).

Here is how it works


The slave block is located just past the uncoupler rail

Having also installed staging blocks I found they work very well and are more flexible with handling variable train length but:
* the traffic is slow because trains must be able to stop at the exact location
* mixing staging block and regular blocks is not so great as in random operation, the staging block is always the last to be chosen
* they work only in one direction
Cheers
Jean
My layout videos
latest vid
hump yard
thanks 1 user liked this useful post by JohnjeanB
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