Part 3 - Routes and Automation in EEP
Routes in rigid transit – Classic solution known as mechanical
Note : that the writer of the article is from France and therefor uses French themes, signals, and equipment. The names and initials used in the pitchers and diagrams are kept the same for practical reasons but are explained in English through out the article
In the first two articles devoted to itineraries, we have successively dealt with the definition and generalities followed by the creation of the itinerary and incompatibility tables, this was the preliminary work for the implementation of automatic mechanisms for controlling the management of the itineraries in EEP. With this new article, we get to the heart of the matter with the concrete realization of an automatism.
As a follower of EEP since almost its beginnings, I quickly saw the value of using a mobile commutators (see below) to perform certain tasks. The idea of building my own automations therefore came to mind, especially since the networks or “Anlagen” marketed by Trend © also showed that train management could be based on the use of one or more mobiles. Subsequently, the “schaltautos” appeared, which can be called mobile commutators/MC. (In French they are : commutateur mobile CM) Their use became particularly interesting when new functions were integrated into the programming windows for vehicle track switches (Fahrzeug).
The pitcher to your left shows some models of mobile commutators that can be loaded from the control window : Rolling stock / Road / Road vehicles. The library offers several models. From a strictly functional point of view, they do not differ from each other. Their only difference lies in their visual appearance.
In particular, two functions have offered a major interest for mechanical automation:
- The possibility of modifying the route of rolling stock,
- The conditional triggering of an action according to the state of a signal or turnout.
The combination of these two functions now allows the construction of efficient and reliable automation systems.
Since then, the integration of programming in the Lua language has allowed a new technological step in the development of automation. However, the mechanical model which remained for a few years the only one possible to use in EEP remains today still a powerful tool to ensure the piloting of complex automatisms. It require nothing more then a good dose of logical sense, unlike Lua which requires for those who have not the slightest notion in the field of the computer programming language, the work of acquisition which is more or less long according to his aptitudes.
Passionate about virtual model making and EEP in particular, we do not all intend to be or become expert programmers. EEP by design is an inexhaustible source of leisure that can meet all tastes, the technical aspect being only one possible approach among others. This is why I thought it would be useful for those who do not wish to invest in learning Lua programming, to publish articles on mechanical automations, i.e. on automations operating only with mobile commutators and track contacts.
In the field of automation we can distinguish 3 possible models:
- So-called “mechanical” automations
- Fully digital automation controlled in LUA language
- Mixed mechanical and digital automation.
Likewise, in the article TCO and incompatibility tables, I specified that the management of routes could be carried out in two ways:
- The rigid transit management mode. (french PRA)
- The flexible transit management mode. (french PRS)
This article is therefore strictly devoted to the creation of a mechanical type automation in PRA mode.
PRINCIPLE AND STRUCTURES
The operation of a so-called mechanical automation is based exclusively on the presence of one or more rolling objects acting on track contacts. It is for this reason that I called it “mechanical” automatism to distinguish it from automatisms entirely controlled by a computer program in LUA language. The theoretical diagram (figure n ° 1) below shows the operating principle with the links between the automation and the track:
- Action of the train on the automation
- Action of the automation on the track equipment and signals
- CTsai = track contact itinerary/route call signal
- CTsei = track contact itinerary/route establishment or start signal
The automation consists of 2 elements composed on the one hand of a static structure and on the other hand of a mobile or dynamic element in permanent movement.
The static structure itself consists of 3 elements:
- A track in static support to allow the movement of the Rolling stock acting on the routes,
- Contacts on the same track in static support,
- Signals indicating a logic state.
The track assembly, track contacts and signals constitute the static support.
The interaction between the signals, the track contacts and the rolling stock ensures the realization of the different phases in the life of a route.
Now is the time to call on our theoretical knowledge. Remember the different phases in the life of an itinerary as we saw them in the first part (Stages in the life of an itinerary) :
- The calling of a route
- Compatibility check with other routes
- Putting on hold
- Initiation and establishment of a route
- Execution of the route
- Destruction of the route (Canceling of a route).
Photo 2 above shows us the structure of the static diagram. Each line corresponds to a route, line 1 being assigned to ITN ( itinerary ) 1, the second line to ITN 2 and so on. The diagram shows only 8 routes while in our model we have counted 12 routes (see article n° 2). I have limited myself to the first 8 routes for practical reasons, but it is obvious that our complete automation will have to display 12 route lines.
The tracks allows the mobile (mc) to move and constitutes the support of the numerous contacts who will control the life of the itineraries. Personally, I use the invisible version tram tracks as a support track (they appear under the name unsichtbar in German). As the automation is not intended to be visible, it is preferable to choose invisible hardware whenever possible to limit the total weight of the project file and the computer’s computational load.
Each line is segmented into 5 sections, each corresponding to one of the 5 phases in the life of a route. Only the waiting phase is missing. This is not an oversight, but we will see below how the verification phase conditions the initiation of the requested route or conversely ensures that it is put on hold.
In the right part of each line we see the presence of 2 signals. The first is called a Itinerary/route Call Signal or ICS (french SAI). It allows the mobile to understand that a request to establish a route is requested.
The second is called the Itinerary/route Establishment or start Signal or IES (french SEI). It ensures that the route is locked and prohibits any opening of any route that is incompatible with the one engaged.
The figure n° 1
shows the location of SAI and SEI contacts respectively upstream and downstream of the route area.
The track contacts are at the heart of the operation for the automation. Three types of contacts are used:
- Contacts for signals
- Contacts for switches and crossings (turnout or DSS/french TJD)
- Contacts for vehicles
The contacts are sometimes grouped together in groups of contacts to obtain a more compact arrangement but also for greater clarity.
The figure n° 2
shows two signals on the right side of each route line. Take line ITN 1. We see 2 signals (Id# 0101 and Id 0111). These signals are invisible models with only 2 states (open or closed). The first on each route line is the route call sign (SAI). As we have seen in the theoretical diagram, the contact which controls the closing of this signal is placed on the railway track at a sufficient distance from the route area. It is operated by the train which closes the signal as it passes. The mobile commutator (MC) will then know that a route is requested as we will see later.
Information : From now on, we will call the mobile commutator (MC) Route Mobile Commutator (RMC) because of its precise function in triggering routes. In French they are : commutateur mobile (CM = MC) Commutateur Mobile d’Itinéraires (CMI = RMC)
The second signal is identical to the first, called the route start signal or SEI, it is also an invisible 2-state signal. It is activated by the route mobile commutator (RMC) as we will see below. In the closed state (Stop), it locks the route and prohibits any programming of an incompatible route. So when SEI (Id #0111 in diagram figure 2) is activated it locks ITN 1 until it is destroyed. It prohibits the programming of ITNs 2, 4, 5, 6, 7 and 9 as we have seen in the incompatibility table (Routes part 2 – Fig 9).
The SAI and SEI signals should be considered, no more or less, as indicating logical states.
Figure 3 above shows the SAIs for Route 2 and SEIs for Route 4, as they appear in the EEP 3D Object Editor window. These are in the closed state, which means that ITN 2 is requested but that this call remains on hold. SEI 4 indicates that ITN 4 is running. This route is locked.
In figure 4 below the purple box shows the position of the mobile or Route Mobile Commutator (RMC/CMI). This one is in permanent movement and traverses the static structure from left to right and from top to bottom in an endless cycle.
Any mobile from the rolling stock library can be used. You can take a plane if you feel like it. No matter. The only requirement is that the mobile can circulate at very high speed in order to allow the highest possible reactivity. The schaltautos travel at 400 km / h which is to my knowledge the maximum speed of moving objects in EEP, even for an Airbus for example.
However, same as for the track, it is judicious to choose preferably a “schaltauto” because of its low weight in bytes. Keep in mind that track contacts weigh a lot in the overall weight of a project file. Count on average 1.5 kb for each contact. You will see below that the automation that we are going to achieve requires a lot of contacts. This is why the concern for economy in the size of the inserted objects must be constant. It is better to consume the kilobytes in the realization of the decoration which constitutes an important and highly attractive part in a network.
Figure 5 below shows the course of the RMC (CMI) which scans the entire static assembly. The yellow dotted arrows show the course of the RMC. I deliberately did not materialize the entire route taken by the commutator so not to overload the diagram unnecessarily and stopped at step 8. However, to make the device clear, I marked the jump with a dark blue arrow. back to line 1. At the same time, the arrows inform you about the virtual connections that must be established to jump from one route line to the next.
Two remarks are in order:
- The mobile commutator does not pass on the tracks which hold the SAI and SEI signals. This would be of no interest and would even be counterproductive because the journey of the mobile would be lengthened and therefore would increase the response time.
- It is possible to further reduce the traveling time of the mobile by removing the intervals between the phases on each line. There is then only one much shorter segment per route line, which further reduces the response time of the automation.
The static element then presents a much more compact configuration as shown in Figure 6 below:
However, for beginners, I strongly recommend the segmented form to avoid errors which are always possible.
The mobile commutator must display one of the 5 routes that you have previously declared in the editor provided for this purpose and which can be found in the drop-down menu « Routes» ou « Routen »for the German version in the menu bar.
The routes (itineraries) listed below constitute the phases specific to the CMI and condition the names of the different steps for the life of the CMI routes:
- 1 APPEL = 1 CALL
- 2 VERIFICATION = 2 VERIFICATION
- 3 ENCLENCHEMENT = 3 ENGAGE
- 4 ATTENTE = 4 WAITTING
- 5 NEUTRE = 5 NEUTRAL
Important : The five routes planned for the CMI actually constitute the state in which the commutator must be in or have in order to act on the contacts. This type of route should not be confused with the route for trains. It is only used and applied to the CMI.
I recommend numbering the routes as I did above, to be able to find them more easily at the top of the list in the drop-down menu. Without numbering, the states of the mobile commutator will be broken down alphabetically among the other routes you have created for your trains or road vehicles.
We will now call CMI “state” what appears as an itinerary selection in the selection window, the term route itinerary must be strictly reserved for the trains themselves to avoid any risk of confusion.
In figure 7 above, the commutator is in the “4 WAITITNG” state, which means that an approaching train has requested a route but that this request has not been taken into account, another route incompatible with the one requested is in progress.
This figure gives us a snapshot of a CMI in the “WAITING” state. Note that the speed at the time of the screenshot was 404 km / h. In fact, the speed on the course oscillates between 398 and 404 km / h.
CONSTRUCTION OF THE AUTOMATION
Route Itinerary line
In the figure n° 4
, we have seen the automated route management system as a whole. We now need to go into the details of each route line.
We have in figure 8 above, the lines of routes 1 and 2 of our network. Remember that ITN 1 corresponds to the route PARIS MARSEILLE VIA TRACK 2 and ITN 2 to PARIS MARSEILLE VIA TRACK 3.
We can see here that the route line is segmented and that each section corresponds to a phase in the life of a route. We will proceed step by step in chronological order
The call is made by an approaching train which activates a route call signal or SAI by a contact point placed on the track.
Take the example of ITN 2. The contact point is programmed as shown in figure 9 below:
The Itinerary window indicates PARIS-MA V3. This is the route programmed in the routes menu. Any train whose route will be PARIS-MA V3 will act on the contact and cause the closure of signal 1002 which is a route call signal. Conversely, a PARIS-MA V2 programmed train will not act on this contact but will cause the SAI 1001 to close.
Figure 10 shows the 3 SAI contacts points acting for ITN 1, ITN 2 and ITN 6:
- ITN 1 – PARIS MARSEILLE track 2
- ITN 2 – PARIS MARSEILLE track 3
- ITN 6 – PARIS GRENOBLE track 3
As a general rule, SAI contacts will be grouped together at the same point on the approach track.
Personally I locate these contacts by using invisible tram tracks placed in a tight a circle, invisible in 3D, but which allows to quickly locate their location in the 2D window.
Now let’s see how the call will be made step by step. Initially, the situation is as follows (Fig 11):
No train is approaching. No route is requested or being executed for either ITN 1 or ITN 2. All SAI and SEI signals are therefore idle.
In Figure 12, a train has just passed through the route contact area. This train is programmed PARIS-MARSEILLE TRACK 3. This route corresponds to ITN 2 in our nomenclature. He therefore has activated the SAI 1002 contact to switch this signal to the closed state. During this time the route mobile commutator or CMI sweeps the static structure of the automation.
When the RMC (CMI) enters the calling area of ITN 2 line, the contact will act on it because of its programming. This contact is of the vehicle type:
The CMI enters the ITN 2 route line in the ” 5 NEUTRAL ” state. We will see in the chapter Setting up and running a route later in this article, how and why the CMI displays this status when entering the route line. ligne d’itinéraire.
The contact on the call segment of the line is programmed with a condition. The first red box specifies that if 1002 sai signal is in the off state then the CMI will take the ” 2 VERIFICATION ” state as indicated in the second box.
As the SAI 1002 has been put in the “off” state or closed, as desired, the CMI route changes from the state 5 NEUTRAL to state 2 VERIFICATION. It should be noted in passing that the “Route” condition window indicates “All”. For more logical rigor we could have mentioned “5 NEUTRAL”. However, as the CMI returns to the neutral state each time it exits the route line, specifying this point does not change anything and does not create additional security.
In order to focus on the succession of steps and the programming of the contacts, I will not develop here the question of the implantation of the SAI call contacts which must be placed judiciously on the track. This question will be discussed later.
The compatibility verification
The verification consists of two stages:
- The actual verification
- The validation of the route request when no other incompatible route is being performed.
Remember that the incompatibility table showed us that ITN 2 is incompatible with the following routes, for a total of 11 routes:
ITN 1 – ITN 2 – ITN 4 – ITN 5 – ITN 6 – ITN 7 – ITN 8 – ITN 9 – ITN 10 – ITN 11 – ITN 12
The vehicle type contacts which will make it possible to check whether a route incompatible with the one requested is being performed are grouped together precisely in contacts called “groups Contact ” as indicated below by the red arrow.
This group contact contains as many “vehicle” contacts as there are incompatible routes. So here we will have 11 contacts ensuring the verification.
This partial view of the ITN 2 group contact window shows us that there are 11 contacts. Now let’s see how each contact is programmed.
As an example, I have used the verification contact for ITN 5. This verification is against to the route start signal or SEI. Remember that this signal ensures the triggering of a route while ensuring its protection throughout the execution phase. In the case of ITN 5, the verification is carried out on SEI 1105.
The other contacts are programmed identically except of course that for ITN 1 the condition will apply to SEI 1101 or SEI 1110 for ITN 10.
So we observe that if an ITN is running its SEI will be closed (stop) and will change the state of the CMI from 2 VERIFICATION to 4 WAITTING.
The verification itself having been carried out, assuming that no incompatibility has been detected, the route request must be validated to make it executable.
This is the function of the contact identified in Figure 19 by the red arrow.
The programming window for this “vehicle” type contact shows that if the CMI is in state 2 VERIFICATION then it can take state 3 ENGAGE, which will allow it to act in the next phase as shown in figure 19.
Conversely, we have seen that in the verification phase, the detection of an incompatibility having caused the CMI to switch to state 4 WAITING, it will not be able to switch to state 3 ENGAGE which validates the route request.
Engage is the phase in the life of an itinerary by which:
- Any programming of another route will be prohibited
- The execution of the route is made possible
The engage/establishment is achieved by closing the Itinerary/route Establishment or start Signal or IES (french SEI). In our case with ITN 2, this establishment is effected by closing the SEI 1102. Once an ITN is validated, it is important that the interlocking be done as quickly as possible to prevent another route from being in the meantime. program.
Figure 20 below shows us which elements of the automation are implemented during this phase.
Note that in a more compact device like the one shown in the figure n° 6
above, the SEI contact would almost be attached just after the vehicle contact, causing the CMI to switch to the engaged state.
Figure 21 to your left shows the programming of the SEI contact of ITN 2.
Figure 21 to your left shows the programming of the SEI contact of ITN 2.
We can see that for ITN 2 to be locked, the necessary condition is that the CMI is in the 3 EBGAGE state. We saw above that if a route incompatible with ITN 2 had been running, the CMI would have entered the 4 HOLD state. It therefore could not have acted here on SEI 1102 .
Once SEI 1102 is closed, ITN 2 is protected for the duration of its execution.
As ITN 2 is now active, the call function provided by the SAI 1002 is no longer necessary. This is why it is appropriate to turn this signal back to the open state at the same time.
Figure 22 above shows the elements that come into play to terminate the route request. This operation is performed by the CMI on the SAI 1002 contact.
As for engage, the deletion of the request to establish ITN 2 can only be performed if the CMI is in 3 ENGAGE state. This means that if the CMI at the end of the verification phase is in 4 WAITING state, it can’t change the SAI 1002.
The route request is maintained and when the CMI presents itself again on the call segment of ITN 2, the cycle will start again as we have seen above and this as many times as ITN 2 can not be authorized due to incompatibility.
The establishment and execution of a route
We are now in the phase that will allow the train to travel the requested route. Two steps must be distinguished:
- The establishment consists in correctly positioning all the switches and crossings of the route concerned and possibly switching the intermediate signals between the entry point of the route and its exit point.
- The execution consists in allowing the entry of the train on the route by opening the entry signal of the route.
The contacts actuating the turnouts are all grouped together in the contact group as shown in figures 24 and 25. Note in passing the position of the signals SAI 1002 and SEI 1102. This configuration thus remained throughout the execution of ITN2, unless a second convoy show up asking in turn to enter ITN2. In this case the SAI 1002 would switch to the closed state but the request would be put on hold since ITN 2 is incompatible with itself.
To program this phase, all you have to do is take the turnouts one by one and program their direction, either in direct layout (Main branch) or in deviated layout (Branch).
Note that condition 3 ENGAGE ( french 3 ENCLENCHEMENT ) must imperatively be entered in the programming window of the turnout contact, otherwise we would inevitably have unwanted operations.
For example, the contact of the Ag 303 turnout at the exit of track 3 is well programmed to allow the train to access track 2 in the direction of Marseille. Condition 3 ENGAGE (french 3 ENCLENCHEMENT) is well mentioned.
- S 21 at the entrance of ITN 2 on track 2
- S 34 at the exit of the station on track 3
However, the figure n ° 27 below, materializes in the red frame the presence of 3 contacts signals , in this case S 20 – S 21 – S 34. Without going too much into the question of the SNCF France (Société Nationale des Chemins de Fer / National Society of Railways) signaling , it is advisable to know that S 21 which is the entrance signal of ITN 2, is a signal with slowdown recall.
In the present case, ITN 2 points the train to track 3 therefore in a deviated path with here a speed limit of 30 km / h. Signal 21 in figure 28 clearly shows the speed of 30 km / h. However, this signal is preceded by a warning signal S 20 to slow down with horizontal yellow lights in the previous safety block It therefore does not appear on the OCB. However, it should be programmed linked with S 21.
S 21 displays here the speed limit of 30 km / h to allow to safely cross in to the deviated position.
The signal here shows the 30 km / h (fixed lights) or 60 km / h (flashing lights) slowing reminder type equipped with a type G marker with 5 lights in the left part. There is an H marker with the same functionalities but displaying 6 lights in its left part.
The signal on the right is located at the exit of the previous block, i.e. approximately 1.5 km before S 21. It must be programmed as a slowdown announcement as shown in figure 30. (below)
This signal is of type E with 5 lights and as for the slowdown reminder signals there is a model of type F with 6 lights.
Signs E and F also display either 2 fixed lights for slowing down to 30 km / h, or 2 flashing lights for slowing down to 60 km / h.
Figure 30 shows the programming of the ITN 2 entrance signal. It is important to remember that only state 3 ENGAGE (french 3 ENCLENCHEMENT ) allows this programming.
The various signals installed on the route must comply with this condition.
Destruction of the route
In this last phase, the segment is called the destruction segment as mentioned above in the figure n° 8
. Strictly speaking, it is not a question of the destruction of the route but rather the destruction of the programming as it was carried out throughout the course of the CMI on the ITN 2 .line. When the mobile approaches the segment destruction it can either be in the “3 ENGAGE” state, or in the “4 WAITTNG” state or even in the “5 NEUTRAL” state. If the CMI is neutral there will, of course, be no change. The presence of this contact at the end of the route line now explains why the CMI always shows up as NEUTRAL 5 at the entrance to each route line.
Figure 31 below shows the location of the vehicle contact ensuring the reset of the CMI to the state 5 NEUTRAL .
It would be much more dangerous for the management of the routes for the CMI to keep its last active programming out of neutral because it could have an untimely action in the following route lines. This is the reason why the NEUTRAL state exists. No action is possible with this state other than calling the route to segment 1.
The destruction of the route which will free ITN 2 and make it possible to establish another waiting ITN will be done by the rear of the train when it leaves the transit area of ITN 2. We have seen above that the protection of the routes is ensured by the SEI. In the present case SEI 1102 is active and therefore it should be switched to the open state. The signal contact in the red box restores SEI 1102 to the open state. For practical questions, I materialized the positions of the destruction contacts by invisible crosses in a 3D window:
The rear of train action of resetting SEI 1102 to open terminates ITN 2’s full life cycle since the call was made.
Figure 33 shows the programming of the ITN 2 destruction contact when leaving the transit area.
It is important that the route window is well filled in. The SEI 1102 only concerns ITN 2 therefore only the trains programmed PARIS-MARSEILLE by track 3. Not setting this constraint would lead to untimely operations because other routes exit by track 2 with the effect of the presence of other destruction contacts. ‘other routes such as ITN 1 and ITN 9 are at the same location.
POSITIONING OF CONTACTS ON THE RAILWAY
Two contacts are positioned on the railway track:
- The SAI route/itinerary call signal contact
- The SEI route/itinerary establishment signal contact
To ensure trouble-free operation, a few rules should be observed.
Positioning of SAI
Full track call with an ITN entrance signal equipped with a type B panel
A train approaching a route must call the requested ITN as far as possible:
The SAI contact in this case must be placed just at the exit of the previous block, ie between 1.5 and 2 km depending on the length of the block. These are the automatic luminous block (BAL) which equip lines with heavy rail traffic. On lines with reduced traffic (Restricted Permissively Block or BAPR) the contact can be placed much further.
Important : The rule to be observed is to ensure that no automatic blocking signal is interposed between the track contact and the ITN signal which opens access to the ITN.
Full track call with an ITN entrence signal equipped with a type G or H panel
We saw above that there are different types of signals showing the slowdown or the slowdown reminder.
It should be remembered that type G or H signs are equipped with slow-down lights at 30 or 60 km / h for crossing switch junction zones. These signals are preceded by a signal with a type E or F sign announcing the need to slowdown.
Figure 35 below shows the position of the track contact of the route call signal. We see that this contact is placed 2 blocks before the route entry signal. Of course, the signals have been placed here very closely together to clearly visualize the general diagram. In fact, the signals are distant from each other by an average distance of 1.5 km, a distance which corresponds to the average length of a block.
During phase “3 ENGAGE”, the CMI switches the ITN entrance signal to the slowdown state of 30 or 60 km / h depending on the programmed route. A logical link between the slowdown reminder signal and the slowdown warning signal switches this warning signal to the idle state at 30 or 60 km / h depending on the situation.
Signs E and F have the same appearance with the slowing warning lights placed horizontally. The difference between panels E and F is the number of lights on the vertical part of the target. In our present case this difference is irrelevant.
Of course it is the same for the signals G which have 5 vertical lights and H equipped with 6 vertical lights.
For your information, this difference is explained by the presence or absence of the maneuvering light
Figure 36 tells us that route entrance signal 3 is coupled with the previous signal. Appropriate logical connections should be made so that the states of the E or F type announcement signal correlate well with those of the route entrance signal.
Another solution is to place a warning signal lane contact on each “Engage” segment of the affected routes and program it to display idle speed with the passing of the movable commutator.
Route call from a station
Here, we anticipate somewhat the flexible transit that we will study in the next section devoted to routes.
In the programming of rigid transit routes of the model we have studied, we can observe that if a train stops at a station it locks its ITN for the entire duration of its stop and during this time prohibits any programming of another incompatible route. We will see in more detail how to make rail traffic more fluid in the construction of flexible routes.
What interests us here above all is the correct positioning of the route call contacts.
Figure 37 shows the location of a route call signal contact in the dockside train stopping area on track 3 of our passing station.
All that remains is to program the contact with a release delay equal to the duration of the station stop.
In this case, the route entry signal is signal 34 which will authorize the departure of the train once the ITN has been engaged and established.
Positioning of the SEI
The diagram below in figure 38 shows a correct positioning of the contact (ZC) allowing the opening of the route engagement signal.
This diagram shows us that the protection of the route is perfectly assured. We assume that train 2 is waiting to enter the route occupied by train 1. This train 1, crossed BAL ( block )signal and set it to red thus ensuring its protection from the rear, then it activated the SEI contact signal (Route establishment signal), placed in ZC, causing the SEI to fall back to open. Train 2 which had requested to enter the route then sees its request taken into account. The ITN entrance signal turns green as shown in figure 39. However, if this train does not stop at our station, it will not be able to catch up with train 1 as soon as the BAL signal for block 1 is closed.
On the other hand, figure n °39 shows us a bad positioning of the SEI open contact. We see in this case that train 1 actuated the SEI contact and therefore released the ITN. Train 2 was therefore able to enter the route. To make matters worse, train 1 was stopped because the BAL block signal is closed.
In this example it is easy to understand that we will see train 2 catch train 1 because of the bad positioning of the SEI contact in ZC area.
Here we are at the end of this presentation of rigid transit itineraries that I wanted as detailed as possible for those who do not fully master EEP. Assuming that it is by forging that one becomes a blacksmith, I can only advise you to create a small network on the same model as the one shown in these sheets and, starting from there, by following the instructions in this sheet to build the automation with all the contacts duly configured.
Some will quickly see in passing that the model I am proposing can be simplified but the formula I have chosen takes into account educational needs. Indeed, I wanted to be as explicit as possible with a modeling of the automation developed in a very detailed way. It will be open to everyone to simplify my basic model.
I will come back to the simplifications to be made in a future article. Likewise, some may notice that there may be other mechanical automation solutions than the one I have developed in this document. There are obviously many possible models. It is up to everyone to compare the advantages and disadvantages of each model. For my part, I usually prefer the formula that uses less kilobytes, a concern that is all the more important when trying to develop complex networks.
In the meantime, I wish you a good reading and I invite you to consult the EEP-World site and ask me all the questions you deem useful for a better understanding of the subject.
This article is now complete. If you have any questions or suggestions, please give us your feedback in the leave a reply input box below.
Thank you for your helpful comments. Have fun reading an other article.
This article was translated by Pierre for the English side of the EEP-World from the article written by François for the French side of the EEP-World.