stan2004 posted:Yep. I can see your point about sensors in each controlled block for more precise stopping. I showed sensor2 in Block B which would do that...but the taxi would simply stop as soon as it entered unpowered Block A. So while I believe the stopping point would be somewhat repeatable, if you've already "cut" your blocks then you'd have to re-layout track sections to change the stopping point. Clearly just moving the stopping sensor would be preferable in such a case!
I like the time-delay idea so that both taxis are stopped for a while. Adds suspense and drama! To that end, if using low-cost relays, I'd suggest using a so-called Delay-ON relay module ($1-2 on eBay). So in this application a Delay-ON relay would delay application of power to Block A. That is, when taxi enters Block B and hits sensor2, a relay swaps power from Block B to Block A. But by inserting a Delay-ON relay, the power to Block A will be delayed by, say, 10 seconds...so both taxis will be stopped for an interval.
And that brings up another idea. If you use a Delay-OFF relay module (also $1-2 on eBay), you can protect the solenoid in the unusual case where the taxi stalls/derails/whatever right on top of sensor1. In normal operation, I figure sensor1 will trigger for a second or so as the taxi passes over it. If this controls the power to the "Y" solenoid, then the solenoid gets power for 1 second which should be plenty of time to flip the "Y". But if it stalls, the solenoid would get continuous power which is generally a bad thing. A Delay-OFF relay could be set to turn off power to the solenoid after 1 second (or whatever).
Addendum:
I dug up this thread where another member had an application somewhat similar to yours. I bring it up in case you're not familiar with these attractively-priced eBay relay modules:
In that thread, I showed how to hook up 2 regular (non-latching) relays on the right module to "make" a latching relay. Last time I looked, a latching relay module with "set" input and "reset" input and screw-terminal connections (so no soldering) is about $10 each on eBay.
Stan, Lots of good ideas as usual. Thanks !! I'll have to look into the delay on and delay off relays on ebay. I use the ebay relay modules already that do not have a delay such as the one shown in your schematic. I'm planing on adding an on/off toggle switch to power all blocks. Then I can run just run one taxi through the reversing loops or have the scene control.
I still like the idea of having several, maybe 3, taxi's cued up at the station rear in addition to the taxi in the front. I could envision how that would work: When the front taxi moves out, the first cue taxi advances to the front. The remaining two cue taxi's advance in position, one taxi at a time. When the taxi returns from the loop, it stops at the back of the rear cue. Delays would still be used, however all the taxi moves must be completed before the loop taxi returns. Also, this would only work if the cue taxi's were manually placed in their starting position. Seems like this scene should work if cue size is varied to 1, 2, or 3 cue taxi's on the layout.
