Thank all.
This was very informativ.
Guy
Modeling CNR in the 50's
rrinkerI would (and plan to) use a relay in all cases, just to make the switching faster and avoid any dropouts. $3.38 on ebay gets me TWO DPDT relays with 12V coils that draw less than 40ma, and have contacts rated at 10A ($1.38 for the relays and $2 shipping). So less than $2 per reverse loop. And a PSX-AR is how much?
Yeah but...
The whole premise of DCC is to automate all this stuff and relieve us from all the DIY tedium - "operate the trains, not the track". Your scenario of using the tortoise contacts to reverse the loop still leaves you with the job of having to manually operate the switch. If you get distracted, you get a real short that takes out a hunk of the layout. My reverse loops, being quite unprototypical for a mainline, are hidden. When I send a train into the loop, I just want it to turn around and come back. I'll gladly pay the $54 for the PSX-AR for that convenience.
Just because it's possible to DIY it doesn't mean that you should. How much other progress on the layout is not happening while you design, shop, assemble, test and debug these little inventions? It's all about the value of your time and the aspects of the hobby you find interesting. Do you want to be a model railroader or an electronics tinkerer? Either choice is fine, but I'd rather spend the cash and have the time to do something I find more interesting.
Besides, having something that has been a pain to deal with since the invention of model railroads work without intervention is really cool!
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
carl425 SNIP Yeah but... The whole premise of DCC is to automate all this stuff and relieve us from all the DIY tedium. Your scenario of using the tortoise contacts to reverse the loop still leaves you with the job of having to manually operate the switch. SNIP Just because it's possible to DIY it doesn't mean that you should. How much other progress on the layout is not happening while you design, shop, assemble, test and debug these little inventions? It's all about the value of your time and the aspects of the hobby you find interesting. Do you want to be a model railroader or an electronics tinkerer? SNIP
SNIP
The whole premise of DCC is to automate all this stuff and relieve us from all the DIY tedium. Your scenario of using the tortoise contacts to reverse the loop still leaves you with the job of having to manually operate the switch. SNIP
Just because it's possible to DIY it doesn't mean that you should. How much other progress on the layout is not happening while you design, shop, assemble, test and debug these little inventions? It's all about the value of your time and the aspects of the hobby you find interesting. Do you want to be a model railroader or an electronics tinkerer? SNIP
Just for the record, my Chama staging loop still uses the manual turnout switches. I know I could use the PSX-AR to automate the turnouts, but I prefer manual control. I can monitor everything via CCTV, so I can throw them manually just like I do elsewhere on visible track.
Ultimately, for control systems for hidden track, you should choose the one that works best for your particular application. There is no single solution that fits all circumstances, so knowing your options in a case like this is always good.
Mike Lehman
Urbana, IL
You have to throw the switch ANYWAY to get the train out of the loop - otherwise you will derail on the misaligned points! There's no more manual operation involved than there is if you hook up an autoreverser.
As for doprouts - no, that's another reason to have the contacts operate a relay. As soon as the Tortoise contacts leave the section of the circuit board inside that is connected to the terminal energizing the relay, it will drop out and chance the phase. Even before the contact crosses the dead spot and touches the other side. And when throwing the switch the other way, the relay will not flip until the contacts touch inside the Tortoise, after they cross the dead spot. In either case, instant contact change from one state to another, with no delays.
As for goofing up and forgetting - yes, it will short, and you'll also likely be on the ground. That's why you have power districts, and if you aren't making your wiring robust enough for the quarter test to work, an autoreverser isn't going to work reliably either.
This is pretty simple stuff, no more complex than the fancy electronic solution. Now, if you want a complex solution to a simple problem - that would be like wiring the layout for MZL with DC, so you can just drive the train and not the track. All thouse relays and contacts just so you cna concetrate on the throttle only - connecting a DCC system, even with feeders every 3 feet, is much simpler. The advantage of the relay, both for loops and frogs (or just the contacts, in the case of frogs - it's not like 10 locos can all be sitting on one frog, creating a need for high current contacts) is that in both cases you eliminate the short, not just correct it. An autoreverser waits for the short, then tries to fix it by switching phase. Hopefully it does, otherwise, time for the circuit breaker to work. And so do the Frog Juicers - they wait until a wheel touches the frog, it if's a short, it flips the frog phase in hopes of correcting it. The reason the all-electronic ones seem 'better' is because they are correcting a fault, which has to happen as rapidly as possible to avoid an interruption. 1ms for a relay vs .01ms for the electronic one may make an actual difference here. But if you are never causing the short anyway, 1ms for the contacts to move and re-engage is plenty fast enough not to get any noticeable drops.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker You have to throw the switch ANYWAY to get the train out of the loop - otherwise you will derail on the misaligned points! There's no more manual operation involved than there is if you hook up an autoreverser.
Not so. My PSX-AR, when it detects the short, reverses the loop "polarity" AND aligns the switch to the track the train is coming from.
Works fine if you always want to make each loop trip run the opposite of the last one. If that fits your operating plan, fine.
All of which makes me wonder how the OP plans to use the loop with the siding inside of it.
Since it is a single track coming into the loop, an exiting train is obviously headed in the other direction. What does the rest of the layout look like?
Will an entering train move into the siding so that another train may pass through, perhaps from the other side of the controlling turnout?
Inquiring minds want to know.
Rich
Alton Junction
rrinkerWorks fine if you always want to make each loop trip run the opposite of the last one. If that fits your operating plan, fine.
Also not so. You can still align the turnout via either a pushbutton or DCC command to traverse the loop in whatever direction you choose.
In case you'd like to actually learn about the product before you continue to disparage it, here's a link:
http://www.dccspecialties.com/products/pdf/man_psxar.pdf
I'm not disparging it, I'm just saying I can do darn near the same thing for a $1 relay and NEVER get a short instead of using a $70 device that waits until there is a short and fixes it. And I really wish they would quit claiming they have feedback, they do NOT, you need some sort of input device for your DCC system to get feedback - none of the PSX devices have Loconet or ExpressNet or NCE Cab Bus.
I know all about Tony's products and how they are SO superior to the Digitrax relay devices (gets posted here ALL THE TIME) yet my PM42 breaker works JUST FINE with sound locos - including articifically loading up one section with ALL of my sound locos at the same time and deliberately shorting it. And it connects to Loconet so I can control each section manually and/or view the status even if the board is up under the layout and I can't see the LEDs.
On a complex piece of trackage, where trying to figure out all the possible combinations of some puzzle trackwork like a multiple double slips - forget about it, use the electronic device. For a simple loop or wye, totally not needed.
Rich,
In fact it is not a ''loop with the siding inside of it''. It is a double track siding located at the North end of a End to End layout that I use as a reversing loop. Either track can be used as the reversing loop.
As it is a End to End layout, no train is allowed to go thrue the loop without stopping. I only use the reversing loop to reverse the trains between operating sessions. So the need of the PSX-AR is not mandatory. As noted by Randy, the use of the turtoise to change polarity is all I really need as the trains are still when I change polarity. The PSX-AR would just be a more convenient way to manage the traffic through the loop, I think.
Guy,
Once it's set up, the PSX-AR just does its thing reliably. Getting back to your original question, a single PSX-AR will handle this job.
Although I don't have Loconet, since I set up my CCTV camera so that it can see the PSX-AR's LEDs at what would be Switch A in the diagram, I can even monitor it, mainly to confirm I've managed to derail something...which is fairly rare, considering it's HOn3 that's down a helix underneath the main part of the layout.