MikefromGERWhy not simply put axle counters at both ends of the critical track and use those to determine track occupancy? Surely there is a way to integrate conventional signalling resources with GPS-based PTC systems, as is done in the ETCS Level 2 systems, although ETCS doesn't use GPS to detect the position of trains, but vehicle-mounted dead-reckoning equipment regularly updated by position beacons (see the Wikipedia article "European Train Control System", section "Levels of ETCS").
PTC coverage affects more than just trains - MofW authorities, Work Zones, Temporary Slow Orders. Interaction with the various carriers CADS systems (which supply the 'back office' information that make the system run. Part of the CADS system is knowing which track trains are being routed to by the signal system). Trains don't dispatch themselves - Train Dispatchers set up routes for each train's operation.
Never too old to have a happy childhood!
BaltACD PTC coverage affects more than just trains - MofW authorities, Work Zones, Temporary Slow Orders. Interaction with the various carriers CADS systems (which supply the 'back office' information that make the system run. Part of the CADS system is knowing which track trains are being routed to by the signal system). Trains don't dispatch themselves - Train Dispatchers set up routes for each train's operation.
I understand that. But that doesn't mean high-precision GPS is absolutely indispensable for PTC - it is just a question of how much hardware a railroad is willing to stick on its track. The NEC, for example, could probably implement full PTC without (I don't know what system they are going to use) because much of what they need is already in place. You can safeguard a work zone by slapping down short-range transponders at the ends of the zone that will trigger a speed reduction or a penalty brake application - whatever you need. The same can be done for slow orders, although I concede it's easier just to define the slow order zone by a few mouse clicks on the dispatcher's display and leave it to the trains to know when they are approaching it and do the necessary. Locos equipped with suitable dead-reckoning equipment will have a pretty good idea at which milepost they are - though not necessarily on which track.
I admit I don't quite understand what you mean about the CADS system - any signalling system that is worth its money should be positively aware where it has routed trains and which tracks they occupy. Lineside detection and identification of the lead unit and detection when the FRED has passed are not witchcraft IMHO.
MikefromGERI admit I don't quite understand what you mean about the CADS system - any signalling system that is worth its money should be positively aware where it has routed trains and which tracks they occupy. Lineside detection and identification of the lead unit and detection when the FRED has passed are not witchcraft IMHO.
CADS is 'Computer Aided Dispatching System'. There are different CADS systems on each of the Class 1 carriers - The various CADS systems were all installed prior to the PTC mandate and are being updated by their manufacturers in accordance with the PTC standard that have been developed by the carriers and the FRA.
It is critical for PTC to be 'RIGHT' when it begins operation in more than a testing enviornment. Tehacapi is a bug found in testing, the bug will be resolved - that is why territories are implemented sub division by sub division. You can't railroad without geography and geography is different everywhere.
Which came first, Computer Aided Design System or Computer Aided Dispatching System?
The use of the same acronym for two entirely different things can be confusing; to me, the context here says that it is an aid for dispatching.
Johnny
We use CAD in the emergency response system, too - as in Computer Aided Dispatch. Depending on the sophistication of the design, such a system can range from simply listing the appropriate response from a table to dynamically recommending proper responses based on known available resources.
F'ristance if Engine 2 is out on a response when a call comes that would normally call for E2's response, the computer can tell the dispatcher to send another unit in it's place.
Normally, the human dispatcher has to "sign off" on that altered response. Once that happens, though, the computer can handle alerting the necessary units, even to the point of using a computer generated voice on the radio.
A far different application of the term than what Balt is speaking of.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
I suspect CA opens a whole host of acronyms.
The only "thing" that knows where a train is, for certain, is a track circuit. The train dispatching system "knows" that a specific train is in a specific spot by inference. That is, train ABC was here, headed east, and now the next block is occupied, so it must be train ABC. The train tracking function in the dispatch system is not a safety system. It's just informational, that is, it's nice for the dispatcher to know the ID of the train occupying a section of track, but it's not vital for safety. Train tracking in dispatch systems have been known to have bugs that cause them to lose ID's from time to time and the dispatcher has to manually relabel.
The PTC problem comes from the train having to know what track it's on. The dispatching systems haven't been safety systems. Safety is all in the field - note in the back office. So, getting safety critical info from the back office is problematic. So, you either have to install new hardware like transponders in the track and antennae on every lead locomotive, or use some other method. RRs have chose to use human verification of info from non-safety critical systems.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
We are supposed to have PTC turned on by the end of summer. There are people in the field working on the hardware getting it ready. I guess it has been causing the approach-lit signals at times to turn themselves on when there are no trains in the block. A few days ago, on a PTC equipped engine with the display alternating between "cut out" and "system unavailable", I twice received a penalty brake application from the PTC system. Lots of flashing red on the screen when the penalty braking is in effect.
Jeff
jeffhergertWe are supposed to have PTC turned on by the end of summer. There are people in the field working on the hardware getting it ready. I guess it has been causing the approach-lit signals at times to turn themselves on when there are no trains in the block. A few days ago, on a PTC equipped engine with the display alternating between "cut out" and "system unavailable", I twice received a penalty brake application from the PTC system. Lots of flashing red on the screen when the penalty braking is in effect. Jeff
Had PTC operational on two Dark subdivisions for 6 months before I retired. Dispatcher and crews had some initial problems in making Main Track switcing moves - the problems were worked out in short order.
Anyone that thinks implementing PTC is as simple as falling off a log is in for a rude awakening.
BaltACD jeffhergert We are supposed to have PTC turned on by the end of summer. There are people in the field working on the hardware getting it ready. I guess it has been causing the approach-lit signals at times to turn themselves on when there are no trains in the block. A few days ago, on a PTC equipped engine with the display alternating between "cut out" and "system unavailable", I twice received a penalty brake application from the PTC system. Lots of flashing red on the screen when the penalty braking is in effect. Jeff Had PTC operational on two Dark subdivisions for 6 months before I retired. Dispatcher and crews had some initial problems in making Main Track switcing moves - the problems were worked out in short order. Anyone that thinks implementing PTC is as simple as falling off a log is in for a rude awakening.
jeffhergert We are supposed to have PTC turned on by the end of summer. There are people in the field working on the hardware getting it ready. I guess it has been causing the approach-lit signals at times to turn themselves on when there are no trains in the block. A few days ago, on a PTC equipped engine with the display alternating between "cut out" and "system unavailable", I twice received a penalty brake application from the PTC system. Lots of flashing red on the screen when the penalty braking is in effect. Jeff
DeggestyLet Congress know that their predecessor acted without knowledge and another extension may be necessary.
With all the career politicians in Congress, their predecessor is themselves...
jeffhergert A few days ago, on a PTC equipped engine with the display alternating between "cut out" and "system unavailable", I twice received a penalty brake application from the PTC system. Lots of flashing red on the screen when the penalty braking is in effect. Jeff
A few days ago, on a PTC equipped engine with the display alternating between "cut out" and "system unavailable", I twice received a penalty brake application from the PTC system. Lots of flashing red on the screen when the penalty braking is in effect.
BaltACDAnyone that thinks implementing PTC is as simple as falling off a log is in for a rude awakening.
That sir, is a most egegious understatement.
zardoz jeffhergert A few days ago, on a PTC equipped engine with the display alternating between "cut out" and "system unavailable", I twice received a penalty brake application from the PTC system. Lots of flashing red on the screen when the penalty braking is in effect. Jeff Gee, with all of that going on, how the heck do you keep your trains in one piece?
Gee, with all of that going on, how the heck do you keep your trains in one piece?
I was lucky, my train that day was 90 loaded (agricultural chemicals) covered hoppers. Trains like that, all the same type of cars and load status, usually don't have a problem. It's the very large, slinky manifests that tend to break in two in those situations. That's why we have a 40mph restriction on some of them. To avoid having to go to suppression when the cab signal goes to restricting.
Our community is FREE to join. To participate you must either login or register for an account.