I have a train route that essentially can be simplified to a dog bone. The station stop is located on the "straight away". I'd like the 253 to only stop "east bound" trains and not "west bound" trains. I envision sensing the direction of the train based upon one of the O22 switch positions.

Here is a diagram for starters:

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Original Post

I don't think that you can get direction from the switches. Maybe from the non-derail part of the switch but that's internal; not available from the posts. That would give you the trigger for direction just like any other isolated track detection method.

I would skip the switches and arrange block detection for the direction that you want to NOT stop the trains; Westbound. The block occupancy detector would activate a timed relay that would put power to the "stop block" of the 253 signal. The timing interval would be enough to let the train pass through.

Eastbound trains would hit the stop block and the 253 would behave in the normal way to stop the train. Then when it continues, it will hit the trigger section but that doesn't matter; it's already past the stopping point. When the timing cycle is complete, the relay is deactivated and the sequence is reset.

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I had to refresh myself on the function of the 253. Essentially, it creates a normally open circuit for the isolated track section. When the train motor stops within the open (unpowered) isolated block, it trips a bimetallic strip that closes the track power circuit to get the train moving again. Then, the bimetallic strip cools and opens the circuit again.

So what you need to do is add a latching relay between the transformer track power terminal (A) and the isolated track section.  The relay is closed by the control rails of the 022 on the right, and opened by the control rails of the left 022. When the relay is closed, track power flows through the relay and the train travels west without stopping. When the relay is open, power does not flow through the relay and the circuit defaults to the function of the 253, train stops heading east, before moving again. 

A spare 022 switch motor could be used as a latching relay. I can draw something up tomorrow for it. 

JD2035RR posted:

A spare 022 switch motor could be used as a latching relay. I can draw something up tomorrow for it. 

I thought an O22 was essentially a latching relay to control the controller lights, so why couldn't one of the installed ones be used? Wouldn't it be a matter of just tapping off one of the outer switch machine posts and connecting it to the B terminal of the 253?

In the diagram you provided, it looks like you had fixed voltage running through the switch, so that’s the voltage that the switch is flipping from one outside 022 binding post to the other. You need track voltage to flip on and off. If you were operating the 022 switches off of track power, then you could use the switch machine that’s in the track diagram, but I’m assuming you’d rather keep the fixed voltage for switch operation. 

D'oh!  You are correct in reminding me that the indicator signal would be from the fixed voltage tap. I've been looking through many conventional wiring tricks and my mind is starting to melt.

You are also correct in presuming that I would like to retain the fixed voltage operation...

Consolidated Leo posted:

I don't think that you can get direction from the switches. Maybe from the non-derail part of the switch but that's internal; not available from the posts. That would give you the trigger for direction just like any other isolated track detection method.

Why can't you get the direction from the O22?  The switch position lights the corresponding lamp in the controller, a low current relay across those posts should give you the detection that's needed.  If it can light a bulb, it can supply a relay.

After a couple cups of coffee, I think there may be a way to do it without an additional relay or 022 switch.  You could rely of the 14-16 Volts fixed as the track voltage when traveling westbound.  Depending on the length/location of the isolated section within the straightaway, the fixed voltage might provide a little increase in speed, but might not be all that different from your track voltage anyway.

I added yellow wire from left 022 to right 022 to always switch the 022 on the right to curve.  Then I added blue wire from right 022 to insulated section to provide power to center rail when traveling westward.  You might have to experiment a bit to use the correct binding 022 posts, but the concept is what I'm trying to depict below. 

No Relay 1

When Train travels on left loop, control rail triggers binding post and signal travels down yellow wire that changes right 022 position to curve and does not send power back to insulated section via added blue wire.  Train stops at signal, then proceeds to loop on right.  As train completes the loop back to 022 on the right, the control rail changes 022 to straight and fixed voltage is sent from 022 to insulated section via blue wire at bottom. Train travels straightaway without interruption, enters left loop and starts cycle again.

 

 

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Conversely, if you wanted to use a spare 022 switch as the latching relay, it would be something like below.

Track voltage to spare 022.  The left loop must always turn off the track power from spare 022.  The right loop must always turn on the track power from the spare 022.  The advantage of this is that you now have track voltage back to the isolated section.  Again, you may need to experiment with actual wiring to opposite binding post.  My diagram is more conceptual - I can't remember exactly how each binding post behaves when the switch is thrown.

However, with track power feeding the switch, you might have the problem of not enough power to throw the switch properly, so you would be back to needing a proper latching relay.  I'm interested to hear how you proceed.

Spare 022 switch as relay

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bmoran4 posted:

Yeah, it looks like I will need a relay. @gunrunnerjohn, I only seem to be able to find DC relays, no low voltage AC ones. Any recommendations for a low voltage AC relay?

You can cobble-together (no soldering required) an AC relay for about $3.50 shipped as shown in this recent OGR thread:

insulated%2520rail%2520relay%2520for%25202-aspect%2520signal%2520using%2520cheap%2520ebay%2520modules

The first module converts fixed AC accessory voltage to 12V DC (requires a DC voltmeter to set the output voltage - see linked post).  The second module is a 12V DC relay module.  Note screw-terminals all around. 

The combo draws about 1/2 Watt of power when active.  In fact, you could dial down the output voltage of the AC-to-DC converter module to, say, 10V DC.  The 12V DC relay will still work fine but this would reduce power draw by ~30%.

 

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The O22 switch feedback voltage doesn't have the current capability to run anything, it's going through the coil in the O22 switch.  It's enough for light bulbs, but not nearly enough to actually run a motorized unit.

GRJ, what you say makes sense.  I was thinking it bypassed the coil (because the solenoid does not continue to buzz after activation like some of the 027 switches), but I'll defer to your expertise.  I must say you always do a great job of balancing the creative and the practical side to all of these electrical adventures that are proposed on this site.  Now you have me wondering what the ampacity is of the coil wire...

I imagine the coil is fairly small wire, perhaps upper 20 AWG, but it is such a short length, could it carry a couple amps for a short period if required?  I know it's likely just a good way to burn up the solenoid, but I'm curious.

022 switch

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I think you'd risk cooking the contacts in the O22 switch.  They're really not designed for continuous duty.  Truthfully, having divested myself of all my tubular switches, I don't know what the resistance is, but I can imagine it's way more than would allow you to power anything but a smoke fan motor.

gunrunnerjohn posted:
Consolidated Leo posted:

I don't think that you can get direction from the switches. Maybe from the non-derail part of the switch but that's internal; not available from the posts. That would give you the trigger for direction just like any other isolated track detection method.

Why can't you get the direction from the O22?  The switch position lights the corresponding lamp in the controller, a low current relay across those posts should give you the detection that's needed.  If it can light a bulb, it can supply a relay.

It's not clear to me that switch position equates to train direction. But if there were an inner loop and an outer loop, and a train in the inner loop is running west while a train in the outer loop is running east, then I would agree. Under those circumstances, switch position would give you the direction indicator to pull this off. But that was not stated by the OP.

Consolidated Leo posted:

It's not clear to me that switch position equates to train direction. But if there were an inner loop and an outer loop, and a train in the inner loop is running west while a train in the outer loop is running east, then I would agree. Under those circumstances, switch position would give you the direction indicator to pull this off. But that was not stated by the OP.

 OP here - I mentioned nothing about inner and outer loops - I did mention a dog bone setup. In such a setup, the switches anti-derail system will change position as the train exits to the straight away.

bmoran4 posted:

I have a train route that essentially can be simplified to a dog bone. 

For what it’s worth, I just tried to use the 022 voltage from binding post to power a train.  At 15v, It was able to power a small dc can motor in a 4-4-2 8206 steamer. It did not have enough power to turn the motor of a 2026 postwar steam engine.

Better off using an actual relay. Right tool for the right job. My apologies for taking the thread down an incorrect path. 

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