Hi, I’m on the 4th plan for a layout, and want to understand the DCC side a bit more than I do before commiting to the layout plan (and ordering the turnouts as a first step). The HO layout would be about 6 x 10’, basically including an internal reversing loop to opposite reversing loop route, and a surrounding external loop, with interconnecting crossovers and a small yard off each main route. From prior (year ago or more) investigation, I’m assuming I’d come down on a Digitrax DCC system, perhaps the Super Chief Xtra 8 amp version. I’m also assuming I’d go with Tortoise turnout machines. Some questions…
a) I presume the Digitrax AR-1 autoreverse modules would be proper gizmos to put on each reversing loop to take care of each(?).
b) I’d like to automate the turnout throws needed before a train exits the reversing loops so trains on the loop-to-loop route could continue automatically . I presume that would require some kind of auto-detect device to determine when a train had fully entered the loop and then throw the entry/exit turnout to the outgoing direction? What will do this (which Circuitron, etc) and how much time required for the turnout throw to complete? Would the train lenght have to be much shorter than the loop because of throw time?
c) I would have two small yards, one of those inside a reversing loop. Do I simply isolate this yard so it sees main track polarity, so when the attached loop polarity is reversed the engines in the yard are not reversed?
d) Can I handle all this with one power system that shares the 8 amps to the 2 main routes and the two yards, as many as 8 engines running let’s say (2 per area), or am I likely to end up needing 2 power systems to supply the 4 areas (the loop-to-loop route, the outer route, and the 2 yards).
I’m sure these are old, basic questions and I promise to also review
If you want to fully automate the loop, Tony’s PSX-AR can run a Tortoise to automatically throw the turnout. The loop will have to be big enough so that a train at average speed won;t try to exit before the turnout is fully changed. If you tend to run at warp speed this could be a problem, if you are more careful and run closer to prototypical speeds, it shouldn;t be that big a deal.
If all switching in the yard can be done without getting into the loop, then indeed isolate it, it’s probably better that way anyway, as yard switching is probably the most likely thing to derail cars and locos and cause a short, so the yard should be on it’s own breaker section.
8 engines running, even all sound, will not tax even a 5 amp system. I’ve had 8 locos running on my 2.5amp Zephyr. The 8 amp systems seem like a bargain because you get 3 more amps for only a slight increase in cost - however the issue is finding a suitable power supply. Most typical power supplies are good only for 5 amp systems, that goes even for the MF615 from Tony’s, it can NOT properly handle an 8 amp system despite their claims. Their own test data shows the voltage dropping off well before 8 amps is hit. It’s basically a 6 amp power supply. Digitrax has the big (and expensive) PS2012 but you will need to aquire 8 amp breakers for it - it comes with 5 amp pigtails to drive multiple 5 amp boosters. 8 sound locos is well within the capabilities of a 5 amp system, and you cna always add a secodn booster should it prove necessary. Either way you definitely want breakers to divide things up, simply to keep a short in one area from bringing the entire layout to a screeching halt.
What are you welding? 8 amps is too much. 5 amps is too much. 3 amps would be plenty.
a) AR1s are nice, but there are solid state auto reversers out there that are better.
b) Use a spring switch with a hex juicer. No need to ‘automate’ the switch at all.
c) Reversing sections should be planned so only on train can be ‘shorting’ the entrance/exit point at once. Beyond that, it doesnt matter what you do within the loop.
d) Each modern loco with sound will draw 0.02 amps at idle and about 0.1 amps running. So 8 amps is silly.
Look at the Zephyr Extra (3 amps) with a DT400 throttle (or UT4 if you wish).
I agree 8 amps is overkill. however you are thinking along the right lines when you ask about the possible need for different supplies for the areas of the layout. Creating power districts can be a good way of managing shorts. Rather than use different suppliies, you could use a power manager like a PM42 to manage these areas.
A spring switch is one with the points held by a light spring. The train always goes the same direction around the loop, and when it comes out the spring allows the points to move so the train doesn’t derail. Once the last car exits the spring once again holds the points in one position for the next approaching train. Even the real guys use these so a crewman doesn’t have to jump down, throw the switch, throw it back again when the train clears, and hike a mile back to the cab. (ah the good old caboose…)
It will reverse the “polarity” (I use the term loosely because DCC is a square signal and really it is out of phase, not polarity) of the frog as needed.
In the interest of full disclosure, it should be mentioned that if the (model railroad) engineer should happen to stop the train while it is partially out of the loop and for any reason reverse the train, he will create a derailment. I would almost guarantee that this will happen.
Also, the switch will want to return to the direction the spring is pulling it every time the side force of the car wheels is removed. This could be in the middle of the car if it is long enough. One is also depending upon the car weight to be sufficient enough to force the points over without derailing. Folks who don’t like weighting their cars to a common standard might have a problem with this.
Finally, the switch itself needs to be free to move. Some minor tightness that might otherwise be overcome by a switch machine could be enough to overpower the “light” spring.
My opinion is that some things that work in the prototype don’t necessarily scale down well.
I’d agree that 8 amps is way more than you need. I’ve got a larger layout than what you’ve planned, and I have no problems at all with 5 amps.
I have a small yard which runs off one of my reversing loops. I use the older version of the Tony’s Trains reverser. The reverser also functions as a circuit breaker, so it protects the yard while also doing the reversing job. This works perfectly. Reversers, by the way, do not cause the engine to reverse. They cause the polarity of the DCC signal to flip, which keeps the engine moving as if nothing had happened at all. So, putting a yard on a reverser section should not affect switching operations in the yard.
I’d go with the suggestion of using the reverser with automatic control for a turnout. That lets you control which way the train enters the loop, which you will want to do if you’re going to have a yard inside it.
Finally, a frog juicer is a miniature reverser used to power frogs in turnouts. The Hex Juicer, as its name implies, actually will drive 6 frogs independently, but the same manufacturer makes 1 and 2 frog units, I believe, if you don’t need 6 of them.
Hi, all. The layout design seems to be firming up, the ultimate question is whether to jump in with both feet (the first foot will be ordering 13 switches, the 2nd foot building the framework / deckwork (mainly cookie-cutter plywood). Seems that 5’10" x 10’ is the outcome.
From the info offerred, I’m still learning, and it’s guiding me otward what I need to determin more clearly. I still lean towards Digitrax. Understand that 5 amps system would suffice. I’ve got to understand more / review to determine the components needed to best accomplish this. Again, I want to understand some things before I dive in. For instance, I presume I’ll want to power some, most or all turnouts.
I’d likely go with some kind of auto-throw for the turnouts on the 2 reverse loops (to align for exiting trains). That implies to me that the end of the entering train must be detected, then the turnout thrown, and enough time exist for the turnout to throw before the engine arrives. How is the end of the train detected? Or doesn’t it work this way?
I’d likely split the layout into 4-6 districts (each reverse loop, the connection between them, and the outer non-reversing parallel route, plus (maybe) the 2 yards (one is on a reversing loop)
A detail I still don’t understand is the issue with the yard on a reversing loop. Let’s say a train is traversing the reversing loop and a switcher is working independently in the attached yard. When the reversing loop train triggers a polarity (phase) change as it enters or exits the loop, what happens to the yard engine if the yard is not isolated? Doesn’t the yard engine (let’s say, going forward) want to reverse direction? I imagine reading my DCC book will clarify this when I review, but your comment will short-cut that detail.
I forget who “Tony’s” is but it rings a bell. Do you suggest I consult with them on exactly how to put together the components once I finalize the lay
No. Reversing the polarity (phase) of the DCC voltage on the track will not affect the direction of travel for locomotives on that track. The reason is that the polarity of the current fed to the motor is determined by the decoder, based on the DCC packets sent to it. So the motor never sees, and therefore never reacts to, the “raw” track voltage.
I’d take most advice from Tony’s, especially recommendations of using any specific DCC brand, with a quite large grain of salt. Tony’s has a business relationship with a specific DCC manufacturer that exceeds the usual manufacturer-reseller relationship in that this manufacturer designs and builds products for Tony’s, that Tony’s sells under their house brand. Not surprisingly, Tony’s tends to push that manufacturer’s DCC products.
Yes, Tony’s Trains does have a “house brand” of train electronics. I think it’s called DCC Specialties. They don’t make DCC systems, but rather components like circuit breakers and auto-reversers. I have some of each, and I’ve found them to be high quality, solid and reliable. They are also a bit more expensive than some of the other brands.
I don’t have the auto-reverse that will throw a turnout, but I would imagine that it throws the turnout as the engine leaves the reversing loop, rather than as the end of the train passes the turnout on the way in. That’s the reason someone warned that the protected part of the loop must be 2 seconds travel time from the turnout. The 2 seconds should be enough time to throw a Tortoise-controlled turnout. If you use twin-coils like Atlas or Peco, they will throw much faster.
Can you also control the turnout manually? If it’s a twin-coil, I’m sure it would be easy to put another toggle in parallel with the circuit. I’d assume that a Tortoise would use a DPDT toggle in series with the PSX-AR to accomplish the same thing. Would that be the way to do it?
Regarding reverse loop auto turnout throw I looked at the PSX-AR. Two questions.
a) if it will throw the switch for exiting the loop when it need to reverse the “polarity”, and it takes about 2 secs for the throw, then I take it I need to locate the loop isolation points about 2 feet into the reverse loop from the turnout to allow for Tortoise throw time? I’m simplifyiong that 60 mph = 88 ft/sec full scale so about 1ft/sec HO. That means my reverse loop isolated section is 4’ less than turnout-to-turnout measurement. Is that right?
b) what if the turnout has been thrown (from prior position when a train exited) by pushbutton before a later train enters the reverse loop? if the loop polarity is still as the last train exited, then I’d guess it’s not “right” for the new train entering until the latter hits the isolation point, in which case of course the gizmo would sense a short and immediately correct the loop’s polarity. If I’ve got that right, here’s the question…would not the PSX-AR throw the turnout when it needed to reverse the loop polarity on train entry, or can it figure out (when a loco hits a isolation point) whether it is entering vs. about to exit the loop and handle the turnout accordingly? Or do I need to leave the turnout aligned as last used when the prior train exited the loop. There’s lots of electronics one the circuit board, so maybe it’s smart enough to do what I WANT???
If you are using twin coil switch machines, there’s a reference in the manual to a PSX-ARSC which is set up to drive solenoid switch motors.
If you want to have a choice of which way the train enters the loop, you will have to control the PSX-AR’s switch decoder to choose the route. Otherwise the PSX-AR won’t be able to set the turnout the opposite way when the train exits the loop. If set via itself, then it knows which would be the opposite setting and can make the change accordingly. If you were to change the turnout manually, the PSX would just try to move the opposite the last known setting.