Hello..
Kinda new to DCC..
Is it typical of the prodigy express when it gets a short to not to be able to recover without pulling the cab from the system? I find it to take to long to recover from a short and it seems like an accident waiting to happen if you can't recover quick enough to stop your train from running away on you.
Of course we try to find and fix shorts, but if a car derails at a switch, causes as short..can't stop the train fast enough. Any thoughts? Any system better?
Thanks
datashead Is it typical of the prodigy express when it gets a short to not to be able to recover without pulling the cab from the system? I find it to take to long to recover from a short and it seems like an accident waiting to happen if you can't recover quick enough to stop your train from running away on you.
If I understand you correctly, the following happens:
A short circuit occurs. Everything shuts down - as it is supposed to.
The short circuit is removed. The command station resumes issuing commands where it left off. But the throttle and buttons have no effect until you reset the throttle software (you are performing a software reset by unplugging the throttle).
I'm assuming in the above scenario that the throttle will not reset itself unless you unplug.
One work-around would be to unplug the throttle before removing the short circuit.
Of course we try to find and fix shorts, but if a car derails at a switch, causes as short..can't stop the train fast enough....
I guess I'm left wondering why anything is running at all after the short occurs. Is it a momentary short that disappears without you re-railing the car? Or are you just losing control of the train without an actual short circuit as the cause?
scratching my head on this one...
Fred W
We'd get a momentary short, nothing shuts down.. but you cannot contol the cabs after the momentary short, unless you unplug and plug back in. During that time, everything just goes as is without stopping. It's an accident waiting to happen, and has happened. I find it takes to long to do the unplug, reset, plug back in. Just thinking we are doing something wrong, or it's just the way the prodigy express is?
datashead We'd get a momentary short, nothing shuts down.. but you cannot contol the cabs after the momentary short, unless you unplug and plug back in. During that time, everything just goes as is without stopping. It's an accident waiting to happen, and has happened. I find it takes to long to do the unplug, reset, plug back in. Just thinking we are doing something wrong, or it's just the way the prodigy express is?
I'm not an expert on this. But what you seem to be saying is that the short circuit protection is not tripping. Two things come to mind.
1) A short circuit not shutting things down is usually due to too much resistance in the wiring. Have you tried the quarter test everywhere along the layout? Lay (not press) a quarter across the track. A short circuit should be indicated on the PE immediately, and everything should stop until such time as the quarter is removed. If this is not happening, either the PE circuit breaker has a problem, or your wiring has too much resistance.
The PE manual may have more information on what kind of reset is required after a short circuit shuts things down. But this all depends on the quarter test working reliably every time, everywhere.
2) How do you know you are getting a momentary short circuit? Without an indication of a short circuit on the PE, there is no way to know exactly what you have. Intermittent contact of the wiring (especially in and near the jacks and plugs) could easily cause the throttles to lose ability to control trains. Runaway locomotives where DC is still enabled in the decoder are not unheard of either.
Agreed. I'd look into the amount and spacing of feeders so short circuit protection works better and faster.
Springfield PA
This is a problem with the Prodigy Advance and Squared systems, too. A very brief short circuit will cause the throttles to display "Svda" and you will need to unplug them from the system to reset them. In the meantime all the locomotives will continue on their way. There is no warning beep or light, so the most common way to find the problem is when you are unable to stop your train, which can be disasterous. I have asked about this on the MRC DCC Yahoo group, and MRC seems to think it is not a major problem. Supposedly the Prodigy Wireless does not have this problem, but I'm not wasting my money to find out. I already have a Digitrax Zephyr, I had bought a used Prodigy Advance at a train show because the branch-line module group I wanted to join ran Prodigy. Well, now the group is converting to Digitrax!
John Fallon
If everybody is thinking alike, then nobody is really thinking.
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jfallon This is a problem with the Prodigy Advance and Squared systems, too. A very brief short circuit will cause the throttles to display "Svda" and you will need to unplug them from the system to reset them. In the meantime all the locomotives will continue on their way. There is no warning beep or light, so the most common way to find the problem is when you are unable to stop your train, which can be disasterous.
This is a problem with the Prodigy Advance and Squared systems, too. A very brief short circuit will cause the throttles to display "Svda" and you will need to unplug them from the system to reset them. In the meantime all the locomotives will continue on their way. There is no warning beep or light, so the most common way to find the problem is when you are unable to stop your train, which can be disasterous.
If this is the issue, then the logical fix (barring MRC making a fix) would seem to be to install one of the fast solid state circuit breakers between the unit and the track. This would act faster than the Prodigy's circuit breaker and prevent the throttle from resetting. Seems cheaper than buying a new DCC system. Just an idea.
There are a few other reasons why we are switching, but it won't be a major expense. All of us also belong to a main-line HO scale module group that uses Digitrax, and most already have Digitrax throttles. We have a series of single track branch line modules, and we don't loop back, so we have several "dead ends" with a 40" drop to the floor.
A very brief short circuit such as a moving metal wheel bridging two rails on an insulated frog won't cause track power to trip, it doesn't on Digitrax either. If they did we would probably not use the system because it would trip too frequently. On Prodigy the issue is that it will cause a loss of control of all trains, but they are still moving, and sometimes toward a dead end. We have also had this caused by someone plugging their throttle in, sometimes all the rest of the throttles will go "Svda".
Our options to fix this are A) Completely tear down and rebuild the modules with all new DCC friendly turnouts, B) Have all eight of us upgrade to Prodigy Wireless throttles, or C) change to a different DCC system. We had a vote and the decision was unanimus. Some of us have Digitrax systems of our own, those that have Prodigy at home will keep it if they want. They'll probably get some extra throttles out of it.
I don't think that Prodigy is a bad system, it is much easier to learn to use than Digitrax, and it is expandable. It is just that with the way we operate and the type of layout we run on, the throttle issue is unacceptable. For the majority of home and club layouts, it may not be as big a deal.
John
The 1156 tail light short protection fixes this problem with my Prodigy advance2. In my situation the trains stop and once the short is eliminated start again, I don’t have to reset anything.
I've had the same problem, momentary shorts causing runaway trains. Hadn't given it much thought due to bad trackwork and figures shame on me. But it now sounds like perhaps the power surge scrambles the cabs and they need reset, or they starve for power and need reset.
I didn't have any breakers on my previous layout and ran it all as one block, the new layout will be broken up and have several breakers and reversers, maybe this will help.
Can you elaborate on using the 1156 bulb?
Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction
jfallon A very brief short circuit such as a moving metal wheel bridging two rails on an insulated frog won't cause track power to trip, it doesn't on Digitrax either. If they did we would probably not use the system because it would trip too frequently.
A very brief short circuit such as a moving metal wheel bridging two rails on an insulated frog won't cause track power to trip, it doesn't on Digitrax either. If they did we would probably not use the system because it would trip too frequently.
A Digitrax system should trip too. High resistance in the wiring will slow trip speed down. It should also recover immediately when the short is gone so there is no run away problem.
Martin Myers
1156 tail light short protection; I learnt about this great idea from Joe Fugate's excellent video series, look for his post in this thread…
http://cs.trains.com/TRCCS/forums/t/127623.aspx?PageIndex=1
If you click on his video link just be patient it does work!
More discussion here;
http://www.members.optusnet.com.au/nswmn/1156.htm#i1156test
A simple search will find all you need to know if the above is not enough, hope this helps as it works great for me.
Thanks everyone for your thoughts on this. We tried a Prodigy Advanced tonight, and it worked great, any momentary shorts did not let us loose control what so ever, never got a SVDA message on the cabs, and when we tried to short it, it would stop, and we had full control right away after the short, unlike the express where you had to reset after a momentary short. Lesson learned.
With the express we were even get a short when the train entered and left a reverse loop, not with the advance, it was all good.