Trying Out a New Way to Activate Signals.

[jwse30]

I've got a few areas on my layout where I've got a road crossing multiple tracks. With my old MRC transformer, that meant hooking up a relay to each track's isolated rail to turn on the signals. But with this ZW I got for Christmas, I think I found a way to do it without any relays. I hooked it all up and seems to work fine. Here's a diagram:



It seems to work with nothing speeding up or slowing down when the signals are activated. This also allows for constant voltage running the signals. Best of all, it eliminate 2 relays just for this one grade crossing. When I hooked it all up, I took a terminal block and landed wires for posts C and U on the ZW as well as 2 terminals to hook the insulated rails and the grounds for the signals. This also allows me to add a few always on constant voltage items from this point. I was kinda in a hurry, so I need to go back and put lugs on the wires and label everything before the amount of connections gets crazy.

Any comments or  suggestions?

J White

[lionelsoni]

You did good.  There are a lot of layout problems that have simple solutions not involving relays; and this is one of them.

[jwse30]

lionelsoni

You did good.  There are a lot of layout problems that have simple solutions not involving relays; and this is one of them.

 

 

Thanks. The main reason I started  looking at this circuit is that I am just now wiring this layout. My last layout was a bit smaller, and I used 9 relays on it. If I did all my wiring the same as I did on the last, I think it was going to use 21 relays. The relays I use are $14 each. Cutting down the number of relays will cut down on the cash going under the board.

 

J White

 

[lionelsoni]

What other ways might you be using relays?  There might be opportunities for getting rid of some more of them.

[kpolak]

Nice Job!

Kurt

[jwse30]

Using slight variations of the circuit I drew above,I can eliminate most of the relays. I'll still use a few for block signals. I also have a two spur freight yard that I will use relays to interlock their power feeds as I did on my old layout. (Each switch is fed from a N.O. contact from the other spur's relay; can't turn them both on at the same time)

Another variation of the circuit I drew above is adding a pushbutton or toggle switch to it mounted to the side of the layout for kids to play with. That would involve a switch fed from terminal U and going to the insulated rail. I have a grade crossing that is going to have a mainline with insulated rails activating the signals that also has a short siding. Since the siding is only a few feet long, I figure I'll use a 2PST switch to power up the siding. One of the poles will power up the center rail, the other will trigger the insulated rail.

It looks like I currently have more relays than I need, which was a lot nicer than before I figured the above circuit out.

 

J White

 

[3railguy]

That'll work. You can also use your old MRC transformer with your scheme (no relays) even if it is DC because only one side of the DC path is associated to the trains which will not cause a short. To work an MRC transformer into your schematic, you hook one MRC post to the U post of your ZW. The red signal wire you show going to the ZW "C" post would connect to the second post of the MRC pack instead of the ZW. The signal will only see the voltage of your MRC pack. You can do the same with a cheap AC starter set power pack.

Some of people do what I'm saying here because DC makes solenoid activated signals run quieter. Bon Nelson has discussed this. I have done it with the 145 gateman and it does run quieter. But then some say DC will eventually turn the coil core into a permanent magnet. I don't know how true that is.

[lionelsoni]

I thought block signals might be involved.  If they are anything like the 153, there is a very simple circuit which replaces the relay by a lamp.  I'll go ahead and describe it, for you and anyone who hasn't seen this before.  The description assumes the post-1950 model with number-53 14-volt lamps.

Connect the 153 terminal for the red lamp to the 14-volt accessory supply (or to the center rail if using track voltage).  Connect the terminal for the green lamp to the layout common (the outside rails generally).  Connect the 153 center terminal to the insulated control rail.  Connect a number-57 lamp between the center terminal and the accessory supply, that is, in parallel with the red lamp.  Cover or hide the number-57 lamp.

Here's how it works:  When there is no train present, the red and green lamps are in series and powered by the accessory supply.  But, because of the number-57 lamp in parallel with it, the red lamp receives only about 1 2/3 volts and the green lamp gets almost all the rest of the accessory voltage, about 12 1/3 volts.  When the train passes, the wheels short out the green lamp, giving the full 14 volts to the red lamp.

This trick can be done with a resistor instead of the extra lamp; but the lamp works much better.  If it's more convenient, you can use two number-53s (or whatever lamp your signal uses) in parallel instead of the 57.  You might also want to use the extra lamp(s) somewhere else on the layout, inside a building, on a lighted billboard, or as a streetlight perhaps.

[lionelsoni]

I doubt that magnetizing the armature will be a problem.  But, if it is, just running it on AC again should demagnetize it quickly.

[jwse30]

 That's the first I've heard of using a light to turn off a light. Neat trick. Sounds very much like DC motor control (changing resistance to the field winding for speed control). I'll probably wire one up like that just to say I did.  I think the relays that are already mounted and just need "field" wiring connected will likely win out and get used for this project:

J White 

[lionelsoni]

I have been thinking about some more ways to use the extra-lamp circuit I described above.

It makes sense for the control rail to start at the signal and extend past it a ways, so that the signal stays green until the locomotive passes the signal, then turns red until the last car is some distance beyond the signal.  With this control-rail arrangement, there can be two signals, facing in opposite directions, and each with its own separate control rail.  As the train approaches both signals are green.  As it gets closer, the one that the engineer cannot see turns red.  As the locomotive passes the signals, the one that the engineer was watching also turns red.  When the last car passes the signal, the one that the engineer never saw turns green again.  Then finally both become green again as the last car reaches the end of the second control rail.

Another possibility is to use a single signal, but with two control rails as just described.  The signal's green terminal connects to the first control rail. and the signal's common terminal to the second.  The signal is dark until the train approaches, then turns green.  After the locomotive passes, it becomes red, then goes dark again when the last car leaves the second control rail.

Unfortunately, both of these schemes cannot simply be combined.  That is, unless you use DC voltage to power the signals and put a diode in series with each green lamp to prevent a sneak path.

[2187trains]

Great idea but that application has been around since 3 rail track came about! Still good work figuring it out.  reason relays are used because you can use double pole, triple pole contacts which can activate a host of things at once using different voltages. Cheapest relays i've seen you can get from allelectronics surplus.

ritch

[wyomingscout]

Bob,

Would this work to activate the track in the signal block, too?

I've got the 153 wired to a 153C contactor the way Lionel says to do it.  This ties into a three track section that is blocked.  It works manually, train 1 is supposed to activate the 153C to green and start train 2.  Unfortunately, I can't adjust the 153C either to change to green (not enough weight to power) or else change back to red after train 1 passes the contactor.

Does your idea negate the need for the 153C contactor?

Thanks,

Charle

[2187trains]

Charle:

Depending how electronic savy you are any contactors working on weight just don't work well.  If you were to use the contactor solely to energize the coil of a relay and place a capacitor across in parallel, that will hold the coil close for a short time based on the size and voltage you use to activate. (an outside dc source should be used) Therefore, as the train pases, the coil will stayed energized instead of light or semophore hoping around.

Another method I use is to buy an inexpensive photocell used for outside lights chandalier base and use the light of a street lamp as the light source to activate cell.  This can be placed anywhere the train passes, have nothing to do with lifting up track and wire into appropriate 120 v relay (time delay type an be purchase at allectronics)

I am new to this forum, if it is not inappropriate, you can email me at [e-mail].  I am a TCA member and presently my layout can operate 40 trains & motorized units simultaneously.  I will be happy to share my ideas with you!

 

Ritch

[lionelsoni]

Charle, there is a way to start a train from a signal as another one approaches, without relays.  I use it on an elevated loop in my train room to alternate two trains that circle the room.

Create a stop block large enough to hold the locomotive at least, but, instead of isolating the center rail, isolate both of the outside rails in the stop block.  (They remain connected to each other however.)  Then connect those outside rails to a single control rail (insulated outside rail) some distance before the stop block.  The control rail should be long enough and far enough from the stop block that the stopped train can get out of the stop block while the arriving train is still over the control rail.

Locate the signal at the end of the stop block, that is, where the stopped train's locomotive will appear to have stopped in response to the signal.  Connect the green lamp to the center rail.  Connect the red lamp to the layout common (the outside rails other than the stop block or control rail).  Connect the signal common to the control rail and stop-block outside rails.  Connect the extra lamp in parallel with the red lamp.  (Note that this is upside-down compared to the simple block-signal wiring.)

There is one limitation:  The couplers between the locomotive and the rest of the train must not conduct.  That is, they must be plastic or be insulated.  This is needed so that the locomotive will stop in the stop block, with no connection of the outside rails back to the normal outside rails through the couplers.

[wyomingscout]

Thanks, Bob.  I'll give that a try.  I think I could insulate the connection between the loco & tender with electrical tape to eliminate conduction.

Duh, I even misspelled my name, but that was just poor typing and proof-reading.

I know it isn't, but sometimes even this stuff seems like rocket science to me!

Thanks for the help,

Charlie (got it right, this time!)

[wyomingscout]

Bob,

I wired the 153 as you described and the block works great!  Only I can't make the lights work correctly.  I'm trying to use a road crossing light as the extra lamp.

It has three connections.  One each for the 2 red lights and a common.  The road crossing light(s) should be red (taking the 12 volts or so from the green light) as the idle train blocks the crossing, then turn off as the train leaves the block.  I just don't know how to wire it in to the setup to take the power from the green light when the block is dead as you outlined earlier.  Can you explain the parallel wiring needed?

Thanks,

Charlie

[cjmeyers]

I'm looking to try a very similar circuit for my new layout and combine it with some ideas I have for automatic block routing and signaling. Am I correct in understanding that given your setup, your crossing signal would stay activated even if your train was stopped with no power? (ZW ON, C handle ON, but A and D handles in OFF position) 

Regards,

CJ Meyers

[lionelsoni]

Charlie, if I understand you correctly, you want both lights of the crossing signal to light up at the same time that the block signal is red.  All you should need to do is connect both of the crossing-signal's terminals for the two lights to the block signal's red terminal (which is connected to the accessory voltage that you are using), and connect the commons of both signals together (which are also connected to the control rail).

To summarize:

Block-signal green to layout common
Block-signal red to accessory voltage
Block-signal common to control rail
Left crossing-signal red to accessory voltage
Right crossing-signal red to accessory voltage
Crossing-signal common to control rail

CJ, assuming that A and D are used for trains and C as the accessory voltage, yes.

[jwse30]

CJ, the signals sill work when there is no track power just as Bob Nelson described above. That makes the signals look realistic, but can also cause them to get damaged if left in their operated state too long. Items with coils or solenoids weren't meant to run for long periods of time. They can overheat and cause the coils to either short or open.

Hope this helps,

 

J White

 

[lionelsoni]

That's a problem generally with things like crossing gates operated from fixed accessory voltage, whether using the lamp trick or relays.  As I mentioned earlier, resistive loads shunting the block-signal lamp don't work nearly as well as incandescent lamps do, anyway.  I understood Charlie's crossing signal to be just a pair of lamps, which do make it a very reasonable substitute for the number 57 lamp I prescribed.  But I don't recommend anything other than a lamp or lamps for that scheme.

[wyomingscout]

Yes, my crossing is simply two incandescent lamps.  However, when wired as lionelsoni described, I still have a problem.  The system works well in practice, but not in application for me.

The train on the isolated block activates the block, even with the couplers insulated.  The reason is, the trucks and frames on my rolling stock are metal.  Therefore, if a wheel touches the isolated block and the live track, or if one set of wheels is on the isolated block and the other set on live track, the wheels, axles, and frame carry electricity to the isolated block.

I bought an "ice cube" relay and, after reading older threads on this forum, think that will work.  At least that's the plan for today.  I swear there are gremlins in my layout.  I had half the layout totally isolated from the other, running each with a different side of the ZW.  It worked fine.  Now, somehow, electricity is crossing and each half of the ZW runs the whole setup.  I've looked for the breach in the layout and find none.  So, I'll redo and try the relay out.

Thanks for all the advice.  Something is bound to work.

Charlie

Are we having fun yet?

 

[lionelsoni]

Charlie, I'm sorry you're having so much trouble.  How is your ZW connected to the track?  Is the ZW's U terminal connected to the outside rails (except for the control rail and stop block) of both loops?  If the transformer's connected properly, there must be an accidental connection between the transformer outputs somewhere that you haven't found yet.

As for the car frames' bridging the gap, your train must be coasting far enough that the front truck of each car gets to the gap too soon after the rear truck of the previous car has crossed it.  Obviously there is some slow speed that prevents this; but you probably don't want to have to do that.  A sure fix is to make the stop block longer than the train.

I thought I would try to explain why it is important to use lamps (as you are doing).  They work so well in this circuit because the current that the lamp draws varies as the .55 power of voltage, not proportional to it as with a resistor (Ohm's law).  So the voltage across the lamp increases almost as the square of the current.  The number-53 lamp draws 120 milliamperes at 14 volts; so putting a number 57, which draws twice that, in parallel with the red lamp means that the red lamp gets only 1/3 the current that the green one does when they are in series.  Because of the near-square-law behavior of the incandescent lamps, that means that the red lamp gets only about 1/7 the voltage of the green lamp, or about 1/8 of the total voltage.  Furthermore, since an incandescent lamp puts out light proportional to the 3.5 power of voltage, the red lamp in that circumstance is only about 1/1000 as bright as the green one.

[wyomingscout]

I like the idea of the light, but can't figure out how to make it work.  I have wired the ZW with the U terminals to the outside rails.

As for making the block longer than the  train, I considered that.  The train would have to coast far enough to get the entire train on the block.  That isn't feasible with the speeds I can run - too many curves too close.  I could watch the train more closely and try to stop it with just the locomotive on the block with insulated coupler, but that would be tricky,

The "ice cube" relay is for 24V and doesn''t activate well at 10-16 volts.  I've ordered a DPDT "ice cube" relay designed for toy train applications.  It should be here next week.  I found the dealer in one of the old threads about this problem.

Wiring switches, isolated blocks, etc. is obviously going to be an ongoing concern as more of us dig these old trains out of the attic.  Gotta do something after retirement when it's snowing outside!

If I'm still missing something, please try to explain it again.  Thanks for all the help; we learn something even when things don't go as planned.

Charlie

[lionelsoni]

Is this what's happening?  The train passes over the control rail without incident.  Some distance after the last car clears the control rail, the locomotive enters the stop block.  Once it is completely in the stop block, it begins to coast to a stop.  But the first car after the first insulated coupler gets to the stop block before the train stops, bridges the gap, and restarts the locomotive.  The locomotive accelerates until the car gets entirely into the stop block; and the locomotive again begins to coast to a stop.  But the second car...and so on.

If you're game to keep working on it, I suggest disconnecting the signal until we get the train to stop and start properly.  Something in the signal wiring might be responsible for the cross-connection between transformer outputs, if that problem is still there.  So the only wire that should remain is the single wire connecting the control rail to the outside rails of the stop block.