Designed by Rob and built by Mark, this simple plan has some surprisingly complex problems that can only be solved by Schedules. It evolved from Mark's early work with “Dueling Dampfloks”.
Each block is set up the same with a fixed wait time of 1 minute.
Originally there were seven routes that define the possible connections between the blocks. They are:
- r1 (A2-B)
- r2 (A2-C)
- r3 (B-A1)
- r4 (C-A1)
- r5 (A1-A2)
- r6 (D-A1)
- r7 (E-A1)
Note that all these routes are setup clockwise starting from the upper right hand corner block A2 (“1 O'Clock”). This defines the general direction of the layout as clockwise, and means that “forwards from any block is clockwise to the next”. For example, forwards from C must be A1, and backwards from C must be A2.
Each route is set for “Both Directions”, and all turnouts have been defined for running in either direction. For example, with route r4 (C-A1) the turnout t1 is set straight.
However, during testing it became obvious that all the locomotives being run would have to face clockwise on the layout. This means that a Steamer running counter-clockwise would have to face the wrong way. For this reason, three routes were added to allow a locomotive to run facing counter-clockwise around the track:
These routes were setup counter-clockwise by using “From-To” with a Run Direction of “Forwards”. This is what allows a steam locomotive to run facing in the “wrong” direction for the layout.
There is a single Block Group A1-A2, which is marked as a Critical Section. This means that if a locomotive reserves one block, it automatically reserves the other.
The main goal is to allow trains to share the layout as they follow different patterns at the same time. For example, a freight train moving clockwise while a passenger train moves counter-clockwise, with both of these trains sharing the A1-A2 line in the north. Or a branch mining train that takes coal from the siding D to the town at B, and then goes back to D for more coal. Schedules will allow the operator to define the different paths trains must take, without having to worry about two trains blocking each other. Rocrail should handle all the little details of making sure one train can get past the other and both trains follow their respective paths.
Using just basic blocks and routes two locomotives can be made to randomly move “around each other” on the layout, but not move around with any real purpose. For this reason, Schedules are used to define a “list of blocks” to be followed, and to allow more meaningful, enjoyable operations. Rocrail then uses the Routes to determine how to get from each block in the list to the next block.
When 2 locomotives both want to move into each others block, they will “deadlock” and not be able to move. In the simplest case, a 2 block layout A-B contains a locomotive in A that wants to move to B, and a locomotive in B that wants to move to A. Neither can move until the other locomotive gets out of its block, which the other locomotive cannot do until the first locomotive moves out of its block.
Rocrail must be able to resolve these conflicts, or fail with a message that says “This deadlock cannot be resolved.” Note that you must design your layout to avoid deadlocks where possible, and make sure there is a solution available. Rocrail cannot make the “A-B” example above work, there is no solution. However, with a properly planned layout, Rocrail should be able to control all movements, halting one train temporarily while another one proceeds, and then moving the first train once the way is clear.
Critical Sections are groups of blocks that can only have one locomotive in them at a time. If a locomotive reserves one of the blocks in the critical section, all the other blocks are reserved for that locomotive at the same time. The top side of the Schedules Test Case layout is divided into two blocks to test this principle. A1 and A2 are linked so that if one locomotive reserves either block, it reserves both.
Work started on Schedule testing back in late spring of 2007, but with the onset of Summer, testing stopped for a while. It was renewed in the fall of 2007, with good results.
The first case was to test a single locomotive running a basic schedule, then test two locomotives running two schedules at the same time. For this reason, the first two schedules used were:
- C-A1-A2-C (clockwise, repeating)
- B-A2-A1-B (counter-clockwise, repeating)
Note that these schedules were made to repeat by setting the Schedules drop-down in the Action tab to the same schedule. For example, schedule C-A1-A2-C had Actions > Schedules set to C-A1-A2-C.
Initially, a single locomotive running either of these schedules worked perfectly. However, running two locomotives at the same time would always deadlock in the A1-A2 part of the layout. This was fixed as of svn 1931. After the fix, one locomotive would run the first schedule while the other waits, then the second locomotive would run its schedule while the first waited.
Also, the locomotives used for initial testing were Electric locomotives, so even though they were moving correctly it was not obvious that they were moving backwards when running counter-clockwise
The next set of schedules tested Rocrail's ability to handle changing directions and non-circular schedules.
- C-A2-A1-C (clockwise, repeating)
- D-A1-E-A1-D (both directions, repeating)
As of svn 1942, this worked perfectly. When the locomotive running the second schedule would enter A1, the other locomotive would halt in A2 and wait until the first locomotive was back in a siding. Then the waiting locomotive would continue past A1, and stop in C. The locomotive in the siding would move back out into A1, and the cycle would repeat.
This is an example of a Yard Switcher working while Main Line trains keep moving through the yard's entrance.
Rocrail could already be used to clean the layout randomly by simply attaching a cleaning car to a locomotive and starting it under Automatic mode. But because of all the stopping and starting involved, it was not very efficient, the cleaning car should be run at constant speed when possible. This schedule was designed to clean the layout more efficiently:
- C-A1-A2-B-A1-A2-C-A1-D-A1-E-A1-D-A1-A2-C (clockwise, then both directions, repeating)
This was used as of svn 1946 to clean the layout, and also functioned perfectly.
The direction issue and locomotive placement became a problem when we tried to run the Dueling Dampfloks scenario originally envisioned back in the Spring. This quickly pointed out the following important points about Routes, Direction and Locomotive Placing:
- From To and Both Directions control whether a locomotive is allowed to move one way only along the route, regardless of facing. For example, if a Route A-B is From To, a locomotive can only move from A to B.
- Run Direction controls if Rocrail sends forward commands to the locomotive when using the route. For example, if a Route A-B has Run Direction set to Reverse, and a locomotive has Placing set to default, Rocrail will send backwards commands to the decoder when moving the locomotive from A to B.
- Placing also controls if Rocrail sends forward commands to the locomotive to move forwards along the route. For example, if a locomotive in A on Route A-B with a Run Direction of Forwards has Placing unchecked, Rocrail sends backwards commands to the decoder to make it move to B.
- Run Direction and Placing are combined when Rocrail determines how to move a locomotive. For example, if a Route A-B has Run Direction set to Reverse, and a locomotive has Placing unchecked, Rocrail sends forward commands to the decoder when moving from the loc from A to B.
Once Mark fully understood this, he got Dueling Dampfloks to run very well using these schedules:
- C-A2-A1-C (counter-clockwise, repeating, used by the BR 38)
- B-A1-D-A1-A2-B (both directions, then runs next schedule, used by the BR 74)
- B-A1-E-A1-A2-B (both directions, then runs previous schedule, used by the BR 74)
You can see a short low-resolution video of the Dueling Dampfloks layout in action on You Tube: Dueling Dampfloks Video
Schedules are still evolving in Rocrail, and there are many unused fields in the dialog boxes that illustrate ideas that have not been implemented yet. Some of the ideas that still need to be developed are:
Block Timing This will allow trains to know that they are early, late or on time. Rocrail can then speed up, slow down, or even make a train wait as needed.
Each block already has a time associated with it in a Schedule. If the first block in the schedule is set for 0:00. and the next is set to 1:00, Rocrail should know if the train made it into the block at 0:30 (early), or 1:07 (late) and make a decision based on Time. Rocrail should hold a train in a block if it is early, and perhaps speed the train up if it is late. This is more complex than it seems.
Timetables and Clock Usage This will allow schedules to be repeated only at specific times. Instead of having a schedule run, stop and then just run again, Rocrail should be able to run a schedule at 9:57, then 12:15, then 13:45. This is more complex than it seems, and brings up the idea of “Time” on the layout.
Schedule Groups In the same way that we can link a set of routes into a schedule, we should be able to link a group of schedules into a Run. Note that we need a better word for this concept, but the idea is that the train first runs the Amsterdam to Paris schedule, then the Paris to Munich schedule, then the Munich to Amsterdam schedule.
Train Priority Fast trains should reserve blocks instead of slow trains where possible. However, a slow train must not be stopped indefinitely because there are too many fast trains using the track it needs. This is very complex, and implies aging, i.e. when a train is only a little bit late, you can stop it, but if it is very late, it must run with higher priority so it will not be “deadlocked” by faster trains that reserve the blocks it needs.
Passing Tracks Situations where a slow train is in front of a fast train should be handled as well, with the slow train “pulling to the side” at the next passing siding and allowing the fast train to get in front. This would mean setting up a single schedule with two or more lists of routes, or allowing you to specify two blocks for a single destination in a schedule. For example consider these two schedules:
- A1-C (wait)-A2-A1
We would always use the first schedule if no other train was on the layout. But if a train with higher priority was following this train, this train would use the second schedule and wait in C while the other train moves ahead of it.
Function Triggering When a train completes a schedule, a specific function is activated. This might let a locomotive play a sound when it reaches its destination, or uncouple from its wagons. Using the Yard Schedule mentioned above, this might let one locomotive run 2 trains, by moving into a siding and coupling automatically, running a train out on the layout, moving back into the same siding, and then uncoupling using a Telex magnet.
This is one of the goals of the original Dueling Dampfloks layout, the idea of a switcher running two sets of wagons from each of the sidings while a main passenger train runs the layout.
This is already implemented, but it should be fully tested.
Output Triggering This will allow other actions to be taken when a schedule is completed, such as turning on or off lights, putting power on the rails in an isolated section, or any other kind of electrical action that can be controlled by an addressable decoder.
The following tables show the details for all the elements in the layout.
|s1a1||B-enter, C-enter, A2-in|
|s2a1||B-in, C-in, A2-enter|
|s1a2||A1-enter, B-in, C-in|
|s2a2||A1-in, B-enter, C-enter|
|3||B||A1||all||t1 thrown, t3 straight|
|6||D||A1||all||t3 thrown, t4 thrown|
|6||E||A1||all||t3 thrown, t4 straight|
|1||B, A1, A2, B||cycle: 10 times||-|
|2||C, A2, A1, B||cycle: 10 times||using routes to/from will flip the direction bit of the train|
|3||D, A1, E, A1, D||cycle: 2 times||using routes to/from will flip the direction bit of the train|