I am contemplating a true reverse loop at one end of my DCC-powered layout to turn around trains to return in the opposite direction.
Rather than a manual control or a toggle switch or a stationary decoder, I would like to automate the turnout so that it alternates the direction of the point rails. In other words, a train would enter the loop passing straight through the turnout. The point rails would then throw to the divergent route to accept the train's exit out of the reverse loop.
Taking this concept one step further, the next train would enter the loop through the divergent route and exit the loop through the straight through route.
How can this be set up to work automatically without operator intervention?
Rich
Alton Junction
Rich,
Several solutions and idea fodder: http://www.wiringfordcc.com/track_2.htm#a46
azatrax offers several kitted options. There are diagrams here for several using different types of switch machines that will give you some ideas if you want to wing it on your own: https://www.azatrax.com/reverse-loop-system-1.html
Circuitron's options: http://www.circuitron.com/index_files/ins/800-5400ins.pdf
But see page 29 here for additional comments re DCC: http://www.circuitron.com/index_files/301cat.pdf
Various Digitrax solutions: http://www.digitrax.com/tsd/product/AR1/
Mike Lehman
Urbana, IL
Entry and exit points from a reverse loop are under the control of the tower. Even though it is just one switch, it requires at least three levers in the tower.
First Home signals are always set to RED. So you mut align the switch to the route you want, and then display the signal.
As the train goes around the loop it approaches another RED signal. So you must align the switch, display a RED signal to the approaching train and a GREEN signal to the departing train.
You must interlock the levers so that the plant is always arranged correctly, and you return all signals and switches to the normal position after the passage of the train.
LION thinks the tower is far more interesting that the locomotive.
If you insist on automation, you can put a reed switch about 300 feet from the turn out so that as you approach it, it pulls a relay to align to the enter side of the loop and displays a GREEN signal, and power the loop from the inbound track.
Somewhere in the middle of the loop you install another reed switch, this one breaks the circuit to the relay Which throws the switch the other way, Displays new signals, and connects the loop power to the out bound track, which reverses the track power in flight. The tricky part is the fact that you must swithc your power supply to the reverse position on the fly. Whcih is why DC trains come to a stop in the loop. With DCC you are relieved of the obligation of ditzing with the power pack, since the train is still ging forward.
RAOR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Ritch, you can use a PSX-AR from DCC Specialties to control the polarity(phase) of the loop and a hare decoder w/ a tortise switch machine to control the turn out automaticly. I have been using this arrangement for over ten years with no problems.
John Sawaska
Wisconsin Rapids, Wi
John,
Good catch on the PSX-AR. I was thinking I saw I nice, neat solution complete with diagram somewhere else and I believe that's it. I have great experience with the PSX-AR and IIRC, Rich has some. I've never considered automating my loops, because they're staging and trips either begin or end there, but don't run through for the most part.
Doc for PSX-AR is here: http://www.dccspecialties.com/products/pdf/man_psxar.pdf
It notes that it provides for automated reverse loop operation. See page 12 for the feature that permits two loops to work together without interfering with each other is more than one loop needs to be operated.
See page 4 for the basic loop wiring. The automated loop would be a variation on nthat, I suppose, but the instructions must discuss it, rather than there being a diagram.
What model turnout are you using? Stall or Coil? Is the reverse loop hidden (from a light source) or on top the layout? (Determines IR or photo sensitive detector)
You can automate this with two detection circuits. Although it would be easier to have the switch reset to clear after the train clears the switch.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
mlw8542you can use a PSX-AR from DCC Specialties to control the polarity(phase) of the loop and a hare decoder w/ a tortise switch machine to control the turn out automaticly. I have been using this arrangement for over ten years with no problems.
I've got a PSX-AR installed that automates a reverse loop. It has outputs on the board to throw the turnout. There is no need for an additional device. Mine is controling a Tortoise. The only consideration is that the gap in the loop be far enough from the Tortoise so that it can complete its throw before the train gets there.
richhotrainRather than a manual control or a toggle switch or a stationary decoder, I would like to automate the turnout so that it alternates the direction of the point rails. In other words, a train would enter the loop passing straight through the turnout. The point rails would then throw to the divergent route to accept the train's exit out of the reverse loop. Taking this concept one step further, the next train would enter the loop through the divergent route and exit the loop through the straight through route.
Mine works exactly as you describe.
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.
Lots of interesting ideas, and I appreciate them all, from a reed switch to the Circuitron AR to occupancy detectors.
The PSX-AR plus a Hare decoder seems like the best idea for my needs, but someone suggested that the Hare decoder is unnecessary in that the PSX-AR alone can accomplish my objective. Is that correct?
A little more detail about my layout. I am contemplating building a reverse loop on the surface of my layout at the far end. It will be visible and subject to ambient light. The loop will be just over 20 feet long. I will use either a Peco Insulfrog turnout or an Atlas Custom Line turnout as the entry/exit point to/from the reverse loop. The turnout will be controlled by a Tortoise.
Yes, the Tortoise motor contacts (pin 1 and 8) connect directly to the PSX-AR< no additional equipment needed.
The caveat, of course, is that the loop must be long enough for your typical train PLUS enough track past the gaps to allow time for the Tortoise to move while the train continues to run at typical speed. With this sort of setup, the gaps do not go right at the turnout.
The spring switch plus an autoreverser is the simplest option, but does not alternate the routes, the train always goes in the same side and always comes out the same side. But no worries that the switch won't get thrown fast enough. I posit that it is possible to make a spring switch that slightly snaps over center (like the spring in a Peco turnout, only much less resistance. Only problem might be if you back through the loop so there is a car leading, rather than the weight of a loco. A loco wouldn;t have any problem with this, but a light car might. But it would give the alternating route you want plus still be simple. If you can;t make the loop long enough to allow the space for the Tortoise to operate, a spring switch is about your only choice.
--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 Yes, the Tortoise motor contacts (pin 1 and 8) connect directly to the PSX-AR< no additional equipment needed. The caveat, of course, is that the loop must be long enough for your typical train PLUS enough track past the gaps to allow time for the Tortoise to move while the train continues to run at typical speed. With this sort of setup, the gaps do not go right at the turnout.
rrinker The spring switch plus an autoreverser is the simplest option, but does not alternate the routes, the train always goes in the same side and always comes out the same side.
The spring switch plus an autoreverser is the simplest option, but does not alternate the routes, the train always goes in the same side and always comes out the same side.
Spring switches will work, but the adjustment can get fussy, depending on car weight variation, flange variation, etc. The turnout points need to be free and without binding. So some experimentation for the specific install is likely needed, perhaps even periodic adjustment.
While slightly more expensive up front, once installed and adjusted properly the Tortoise will usually keep working without any further drama.
carl425 mlw8542 you can use a PSX-AR from DCC Specialties to control the polarity(phase) of the loop and a hare decoder w/ a tortise switch machine to control the turn out automaticly. I have been using this arrangement for over ten years with no problems. I've got a PSX-AR installed that automates a reverse loop. It has outputs on the board to throw the turnout. There is no need for an additional device. Mine is controling a Tortoise. The only consideration is that the gap in the loop be far enough from the Tortoise so that it can complete its throw before the train gets there. richhotrain Rather than a manual control or a toggle switch or a stationary decoder, I would like to automate the turnout so that it alternates the direction of the point rails. In other words, a train would enter the loop passing straight through the turnout. The point rails would then throw to the divergent route to accept the train's exit out of the reverse loop. Taking this concept one step further, the next train would enter the loop through the divergent route and exit the loop through the straight through route. Mine works exactly as you describe.
mlw8542 you can use a PSX-AR from DCC Specialties to control the polarity(phase) of the loop and a hare decoder w/ a tortise switch machine to control the turn out automaticly. I have been using this arrangement for over ten years with no problems.
richhotrain Rather than a manual control or a toggle switch or a stationary decoder, I would like to automate the turnout so that it alternates the direction of the point rails. In other words, a train would enter the loop passing straight through the turnout. The point rails would then throw to the divergent route to accept the train's exit out of the reverse loop. Taking this concept one step further, the next train would enter the loop through the divergent route and exit the loop through the straight through route.