I am writing the code to enforce PTC rules for my railroad (BNSF in northern California) and I am wondering if anyone else has tried this. It is VERY complex code and I now have a better understanding of the problems with getting PTC to work on the railroads. My layout is only 39 X 12.5 feet. Imagine the problems for a railroad of ten thousand miles of track.
Any help with resources from the railroads dealing with the PTC code wouldbe appreciated.
Thanks In Advance
Caldreamer
The Pacific Southern has short protection blocks just before stop signals which when occupied AND the signal is read open a relay to the entire block dropping power and stopping the train. This is a very useful feature during operating sessions. Most of the Pacific Southern is under control of PC software.
of course it doesn't (can't) monitor speed to apply brakes on a train that is going too fast.
greg - Philadelphia & Reading / Reading
Monitoring and controlling speed is the easy part. Track occupancy tied to signal control is much more complex. i am currently flow charting (diagraming) the PTC logic. It will help when I have to actually write the code which will be written in java and python scripts thru JMRI to communicate with the loconet. .
This is the "simple" solution...http://www.azatrax.com/exhibit/index.html
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Can already do that with jmri automation scripts. The trick is to actually run the trains EXACTLY like the real realroads and NOT have any accidents.
You ought to look around online for prototype documentation. Wabtec is the manufacturer of I-ETMS, which is already installed in places on BNSF and on Metrolink in LA. That's going to be the standard system for the freights. They probably have put PPT level of detail stuff out for advertising purposes. You might also look at FRA's Railway Safety Advisory Committee, which played a big role in standard setting.
http://mprailway.blogspot.com
"The first transition era - wood to steel!"
Route of Broadway LION is fully automated, and PTC compliant per NYCT usage which is over 100 years old.
LION does not actually have trippers, and signal blocks are in fact station to station rather than signal to signal. Intermediate signals are for looks and display the aspect of the last signal entering a station.
If the signal in front of the train is red, the train cannot leave the station. That signal will clear (to amber) when the train ahead of it arrives at its next station, and will clear to green when that train reaches the next station after that.
LION runs 10 trains on his 9 mile long mane lion. All are controled by the signals. All automation is analog, no computers are used on the layout, but there are track detectors and a whole bank of relays to make the thing work.
LION does not operat the trains himself, he has little plastic people to do that. LION sits up in the tower of the 242nd Street station and works the levers on the life-size GRS model-5 machine.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
caldreamerI am writing the code to enforce PTC rules for my railroad (BNSF in northern California) and I am wondering if anyone else has tried this. It is VERY complex code and I now have a better understanding of the problems with getting PTC to work on the railroads. My layout is only 39 X 12.5 feet. Imagine the problems for a railroad of ten thousand miles of track. Any help with resources from the railroads dealing with the PTC code wouldbe appreciated
You really don't need the real code because you don't need that level of complexity.
PTC really boils down to two things: Is the train going faster than it should for the location and can it get stopped before it exceeds its authority on the main track.
I rather doubt you have all the inputs that the real systems have, plus the real stuff that happens with PTC, the stopping the train part, has nothing to do with the "system" per se, all that is figured out by the systems on the engines. The PTC system doesn't tell the engines to stop, they tell the engine how fast it should go based on the train makeup and geography, and where the authority extends to. The land based PTC system doesn't really even know the exact location of the engines, it doesn't need to know. The engine figures out where it is and then figures out how far it has authority and how fast it should be going and then the ENGINE decides if the brakes need to be applied (well technically it tells the engineer he needs to do something and if the engineer doesn't take action the system does.)
The easiest way to simulate PTC is to have CTC and some sort of feedback to the system that senses train movement. Set up fixed approach blocks to absolute signals and if the signal is stop, the system enforces a a speed reduction curve in the approach block. Added level of complexity, it the human engineer decreases speed faster or the same as the speed curve the system takes no action.
If you have an automated control of trains, it should be completely inditinguishable from PTC. Even on the real railroad, if an engineer complies with the rules he will never know there is PTC in effect, it shuld be totally transparent. The only way your operators or a real engineer should encounter PTC is (other than a fairly complicated initialization rigamarole) the system breaks or the engineer doesn't comply with the rules.
Dave H. Painted side goes up. My website : wnbranch.com
Dave is right, it need not be complex for models.
Like the Lion, I run DC and have PTC, or at least a version of its predecessor, Automatic Train Control.
I have a DC Advanced Cab Control system with detection and signaling. Every interlocking, the most common location for absolute signals, is a buffer section. Trains cannot proceed through the interlocking unless they are assigned both blocks on either side.
And until they have both blocks, the signal is RED. If they run that RED signal, their train stops. The buffer sections are long enough to prevent a "drift though". They simply cannot overrun a RED and get into another trains controlled trackage.
And believe it or not, this feature is basically a free benefit of the fact that I do not use common rail wiring.
No writing code or programing or extra equipment, just proper placement of rail gaps and feeders, and the use of seperate power supplies for each throttle.
Sheldon
I will be running a CTC system using JMRI, but there is a lot more to PTC then just whether a signal is red or not. For example:
1. Is there a turnout at the end of the block and is are the points open or close. What are the signal indications for the switch in both directions?
2. Are there any switches within the block going to a siding, industrial track or branch and in position what are the switch points and the signals for the switches?
These are just 2 examples and do not include the occupancy rules of PTC.
I suggest that your download the PTC rules from the web and read them very carefully.
caldreamer I will be running a CTC system using JMRI, but there is a lot more to PTC then just whether a signal is red or not. For example: 1. Is there a turnout at the end of the block and is are the points open or close. What are the signal indications for the switch in both directions? 2. Are there any switches within the block going to a siding, industrial track or branch and in position what are the switch points and the signals for the switches? These are just 2 examples and do not include the occupancy rules of PTC. I suggest that your download the PTC rules from the web and read them very carefully.
Respectfully, no thank you. I don't model modern railroading and that information is of no personal interest.
BUT, how big is this layout?
Do you really have the running length between home signals to implement all that?
Industrial sidings thrown to the siding generally constitute an automatic red at both ends of the block. It is assumed the train working the siding is in the block. This creates an absolute stop for other approaching trains.
In most cases with CTC, sidings and branch lines represent interlockings and so are home signal boundries, again a red over red is an absolute stop.
Agreed, my system makes no allowence for speed control.
Good luck in your quest,
I believe that in my original post i stated that my layout is 39 X 12.5 feet with a central island. I have a mainline run of over 300 feet. from stating yard to staging yard.
caldreamer I believe that in my original post i stated that my layout is 39 X 12.5 feet with a central island. I have a mainline run of over 300 feet. from stating yard to staging yard.
You did indicate the physical size, you did not indicate the amount of track. My layout space is exactly twice that size, and my total plan calls for 800' of double track mainline. I pull long trains, my signal blocks are long, so even with that much track I have "streamlined" the CTC and signal system - to each their own, good luck.
I did not indicat that my railroad is N scale double track mainline and both tracks will be signalled for operation in both directions.
caldreamer I did not indicat that my railroad is N scale double track mainline and both tracks will be signalled for operation in both directions.
And again, all that makes a big difference in terms of realistic distances for all this exactly to prototype operation. And again, good luck with it, sound like it will make a very interesting layout.
With 800' in HO I still feel the need to compress and simplify some aspects as run times are dramiticly compressed compared to real life.
My CTC is simplified to selecting route and pushing one button to authorize the next block. My turnout controls are also all one button selects the whole route through the interlocking.
There are no intermediate block signals, only absolute signals at the interlockings and approach signals that only show yellow or green based on red or green at the home signal.
While not complelely prototypical, the effect is very realistic, even experianced signal guys don't really notice what is "missing".
The dispatcher can see the location, and movement status of every train. And even though it is DC, mainline engineers only have to control the speed an direction of their train with their wireless throttle - the dispatcher and the control system does the rest.
And, as explained above, if someone runs a red, their train just stops.......
I considered systems like you are planning, but decided against them in the end.
caldreamer 1. Is there a turnout at the end of the block and is are the points open or close. What are the signal indications for the switch in both directions?
This is where you are missing the point. Regardless of whether there is PTC or not, the signal indications will be the same, the speed restrictions will be the same. PTC does not change how the signals work AT ALL. All the CTC is exactly the same as it is outside PTC.
What PTC does is enforce the speed restrictions and stop indications.
Doesn't matter. The CTC indications will be the same regardless of whether there is PTC or not. The speed restrictions will the same regardless of whether there is PTC or not.
And all the occupancy rules in CTC are exactly the same. Nothing changes.
Nah. I work in a dispatching center for a class one railroad and have actually worked on some PTC related projects.