I'm working on an update to my son's layout, and have created a problem. The layout (in HO/DC) has/had a crossover on it where two different control blocks crossed and continuted on their respective ways. No Problem so far.
Then I thought it would be kinda' cool to go straight at the crossover instead of crossing. In effect switch from block a to block b as though it were like a turnout instead of a crossover. From both incoming legs of the crossover of course. I did some research and figured a double slip switch would work nicely, so I got a PECO Double Slip Switch (an SL-90 Insulfrog for anyone who is keeping score) and started the install.
For some reason I did not understand the mechnics of the two sets of points (or frogs, forgive me) on the SL90 and so the problem. For those who didn't know this either, (and for those who may come across this later who also don't know), in simple terms, one of the point sets controls the incoming (entry) track route, and the other set of points determines the direction out of the switch (the exit). That's not what I expected.
entry >P1P2< exit
P2 would be set for one or the other of the entry routes, P1 would determine if the traffic crosses or goes "stright"
I'd love to be able to put a block detector on each leg coming into the switch and let that detection trigger the twin-coil (PECO PL-10l) motor for that leg. Trains almost always run in the same direction counter clockwise, but may come through the double slip from either directon, i.e. reverse.
If a short gap is required it could be pretty close to the crossing as one side of the crossover is sometimes treated as a mainline and the other as a passing siding if two trains arrive at the same time. (The point is that, if set too far back, the trigger for the auto throw could cause a derailment if a train is on the crossing, and the PECOs are instant throws, not slo-mo like the tortoise. I'd think the gaps, if required could be pretty close to the crossing. Also both tracks into the crossing have just exited a tunnel, about 15 or so inches (not scale inches, real inches), so access is not a problem, but visability could be from time to time.
So I should also ask if, with an auto throw feature on the other [Exit]side, can I still have a DTDP contact switch for the reverse directon or manual operation should that ever be necessary.
So:
Is the Hare or the Wabbit workable for DC?
are they usable on twin coil three wire motors like the PL-10
if either of those is NO, any other solutions or web links I can look to?
I appreciate any help given and sorry to be so windy, but I don't know enough to be concise.
I'll probably be back when I can't get it wired up correctly, but I have done my research on that issue and all insurance policies are paid up.
living by my new mantra, if there is an easy way, I can find a way around it.
thanks
Roypea
I'm having a little bit of problem with you terminology, but what I get is that you want to automatically align the turnout using block detectors.
I suppose that can be done, but it seems both expensive and unnecessary. What I've seen most people I know do is align the turnout so that the engine always follows the main line. If you want to switch tracks you throw your turnout to make your divergence, and return it to the main when your train has passed. You do this every time.
I rigged a series of lights on my control panel to show which way the turnout was thrown because I thought it would help my son know which way the turnout was thrown, but it did not make a difference. He still had to learn to return the turnout to the main.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
Thanks Spacemouse, I appreciate the help. The problem is that both lines entering the crossover are, in efect, the mainline. This beast started out as one of Atlas' layouts, from Beginners guide to HO Model Railroading, layout number HO-5 the Senior twice around. In effect it allows the mainline to make two laps around the 4x8 (4x9 in my case) before it repeats itself. I thoulght I'd be cute and go back and install the double slip switch in place of the crossover.
The route works something like this: the first time through the double slip will be set to one direction, and the second time, without re-seting the slip switch, the same train will derail. Not too big a deal, just flop the turnout motor, but if running two trains, I'll have less time, and I thought it'd be nice to automate that throw in the proper direction for the incomming train.
Hope that helps, I know just enough in this hobby to be dangerous, varwee varwee dangerous. But not enough to ash intellegent questions.
Thanks
I'm not familiar with the layout in question, but I get the gist. Basically you have a figure 8 with a double slip. Once through the intersection, you need it to throw it the way your train is coming to prevent a derail.
My advice is to leave it alone and control your train as you have been.
If it is a big problem remove the double slip.
Short of computerization, you will have difficulty both throwing the switch the direction to prevent the derail and the throwing it the direction of your intended route. I suppose it can be done, but what you would need is beyond my current knowledge. You would want a manual override as well. What we are talking about is 16 different possible combinations if you run both directions. That would be hard to sort out with block detection and relay switches.
If I'm reading things right, you have a doubleslip, but you were planning for a double crossover. On the surface, they seem to be similar, but as you have discovered, they are quite different. With the double crossover, there are four sets of points, but only two routings (that make sense), straight, or crossover. All of the approaches are from the point end, or heel of the switch, so you can never approach against the points. With the doubleslip you have two switches heel to heel, and then mashed together. Now you have four routings, and every approach is from the frog end of a switch, so you can approach against the points.
If you were to make some rules for yourself on where trains can be with respect to the double slip, I think it would not be too hard to have a detection circuit of your choice on each approach, and thow the turnout to avoid the switch against you. I think latching relays might do the trick. The only trouble would be if you broke the rules, and detected two trains at once, but then you get what you deserve, right?
Jeff But it's a dry heat!
To simplify your understanding, a double slip switch is mechanically identical to TWO standard turnouts installed point-to-point.
The facing points are not a problem. The train will either travel the straight route or the curved route, but neither will cause any difficulty unless you take the curve at a speed measured in Mach numbers.
The trailing points have to be thrown to accept a train from whichever side of the NEAR frog. Thus, your detector needs to throw the points at the FAR end of the double slip. The way those points connect together, it doesn't make any difference which way the NEAR points are thrown, either route will be clear for running.
Once through the double slip, the detector for the opposite direction will have no effect. It will simply try to throw the facing points in the direction for which they were already set.
If all movements are to be in the same direction, you only need one pair of detectors in the approach tracks, connected to the trailing points. The facing points will have to be controlled either manually or with a panel switch (or pushbuttons) to change routes through the double slip from straight to curved.
If movements are to be made in both directions, both sets of points will need panel controls, but only the one specifying the departure route will be used each time a train passes through. The detector(s) will handle setting the points for the appropriate entry route.
Hope this hasn't been too confusing.
Chuck (modeling Central Japan in September, 1964 - with handlaid multi-slip-switch puzzle palace specialwork)
Edmunds in Latvia http://www.edmundsworld.net HO Transition Era modular layout being built with Faller Car System, DCCar, German Style Signalling, Computer Control and Automation
Edmunds wrote:Why does it matter, what is the status of the "second" switch machine?If I understand this correctly you have:A B\\ //\\////\\// \\C DAny train from A can go to C and D. Any train from D can go to A and B. And so on.The only thing that can derail the trains is a wrong position of a switch machine on the side the train is approaching from. If A-approaching train manages to go to C instead of D, you might be up for other kind of trouble, but not a derailment.Edmunds
The only problem with your thinking is the use of the words, "On the side the train is approaching from." The switch machine on the near end controls facing points, which will point the train to one of the two routes through the slip switch. It really doesn't make any difference which one; neither will cause a derailment.
The critical machine, which MUST be set correctly, controls the TRAILING points - just ahead of the far frog. Set right, the train will pass safely onto either exit route. Set wrong, one lead wheel of the locomotive will get pinched between a closed point and a stock rail, while the opposite wheel will be pushed toward the route centerline - a recipe for derailment if there ever was one.
If there is enough spring in the point linkage, a heavy locomotive might bull its way through. Don't bet that the much lighter freight cars will follow it.
Chuck (modeling Central Japan in September, 1964)
Chuck, you nailed it.
I don't care so much about the leading, or near end, but the trailing end is where the problem is, just as you said. when I've been doing this for a while longer, I'll have a better feel for the traffic approaching the double slip, but for now, I almost have to stop traffic, go to the double slip and "walk" the train through it to see if the point are set safely, as to Chuck's point, and correctly to send the train in the direction I want it to go.
Further, this layout is supposed to be for my son, who is six, and it would be nice if I could "automatically" eliminate this derailment trap for him.
Thus the auto-throw part of the question. In Edmunds diagram, sense or detect approaching traffic on "A" and auto throw the training points in the correct, safe, direction. We'll still manually/electrically control the near points to direct the train on to "C" or "D" as desired.
I can handle block detection on "A" and "B" in the example, but how do I throw the trailing end. BTW, I have a capicitance discharge unit (CDU) on the PECO motors.
Thaks for all the answers, if I can get this last piece of the puzzel maybe I can quit wrecking trains LOL.