Need a schematic circuit for stop / go action for Lionel 132 train station

Based on comments in the original thread, some questions on requirements.

1. Does it need a bleeder path to apply some TBD minimum voltage to keep the E-unit from cycling into neutral?  Or can we assume the engine is locked-in-forward?

2. Is soft-start like the AF station a must-have, nice-to-have, or don't care?

3. Given thermostatic replacements (Lionel #132-44) appear to be $25-30, are there any cost/size/complexity guidelines that, if exceeded, would nix the project?

4. As brought up in the other thread, there are layout-level off-the-shelf control systems with station stop/start capability and many additional features.  Is the focus here is on just a single-station?

Background material:

I can't find it now but while hunting for 132 info I think I read the Nichrome wire has a nominal resistance of 60 Ohms (or something like that?).

Try using one of these modules from the bay.

Yes, Trainman129, great suggestion.  This is the ticket. Had no idea these were so inexpensive.    I see there are several variations and pricing on Ebay.   Thanks for the info!!

Dave

I've used several on my layout and some on the club layout. They work great. You can make them do all sorts of things by using more than one in a circuit. Have fun playing with them.

Jay

trainman129 posted:

Try using one of these modules from the bay.

Can you please provide the name or specification of this circuit board so I can look it up on the internet, or a link to where it can be found?

Thanks,

You probably have a 133 station without the controls.

Direct links to eBay aren't allowed on OGR per terms of use, but copy some of the title words into eBay search and you'll find the module...

Dale K posted:

trainman129 posted:

Try using one of these modules from the bay.

Can you please provide the name or specification of this circuit board so I can look it up on the internet, or a link to where it can be found?

Thanks,

 

I put "time adjustable relay module" in the eBay search box and got a lot like the one pictured here; but not this one exactly. Try that.

Thanks for the replies - I have found one of these circuit boards on eBay too now.  But I do have some additional questions about wiring it for a stop control on a traditional AC, 3-rail layout:

1. I assume this circuit board relay will be activated by connecting an insulated ground rail in the stopping track section to the black terminal marked GND.  If that's so, will I need to install a rectifier on that terminal as well as the red +12V connection (which will be connected to a 12V AC accessory power source), since this is a DC relay?   

2,  What would I connect to the green "control switch" terminal?

3. I assume one of the blue "load power" terminals (probably the NO terminal) would connect to the insulated center rail section, to feed power to the stopped engine once the timer has expired - correct?  

4, Would the other blue "load power" terminal with the circled X (COM) be connected to the AC power ground?

5. I assume this circuit board would have no voltage "leak by" like the 132 station's nichrome wire coil does?  As stated in an earlier part of this thread, that coil still passes a small amount of voltage (about 2.5V AC in my case) as the coil heats up, which doesn't completely stop the newer MTH trolley that I am operating on this loop.  

All your help is appreciated!  

Dale

Dale: These cycle timed relay modules are generic in that they are not made specifically for model railroad applications. The module suggested by @trainman129 back in 2016 may do the job but I have no idea what his plan would have been. It could be done but it would take more than just this module to make it happen.

I will try to address your questions as best I can:

1. No. As you say this is a DC relay module. The DC+ and GND terminals supply power to the module. The GND does not connect to an insulated rail section.

  My standard answer for DC power is to use an AC to DC buck converter that allows you to use AC accessory voltage as an input and get DC voltage out. You can set the output voltage to what you want with a built-in potentiometer. The DC+ and the GND would connect to the buck converter outputs.

Other possible sources of DC power are DC power supplies (like an ATX computer supply) or a wall wart. To see an example of the buck converter I recommend, copy and paste this number into the eBay search box:

323405457109

2. The green "control switch" terminal on the board is the trigger. You would need to have the module setup in one of the modes of operation as outlined in their description (which is not easy to understand):

You see what I mean. Anyway, one of these modes should turn the relay on after the timing cycle has been triggered for the specified delay time. And then the relay should turn off (I'm not sure what mode does that).

The trigger could be done with an isolated rail section, or an ITAD (infrared detector) or an opto-isolator or I would use something like GRJ's track sensor available online from Hennings Trains. It works with the insulated rail section to trigger a small relay. That could be used as a switch to trigger the timed cycle.

3. Yes. The outputs from the relay go to power the stop section of track. One side (NO - normally open) connects to the isolated center rail of the stop track and the other (COM - common relay connection) goes to the track power AC.

4. No. See 3.

5. Right. No leaks to keep the E-unit engaged in the forward direction. This would only work if you have the E-unit switched to lock it in forward.

I have used a microprocessor and relay to stop a train, toggle the E-unit into neutral, then reverse, and back to neutral so that the train is stopped with the lights on for a period of time and then proceed. If you like that idea, let me know and we'll start a new thread on how to use an Arduino to control a stop block.

As I understand it, you already have a #132.  This of course has an isolated center-rail section to starve track power to the trolley...but does not use the insulated-outer-rail for triggering.  If you don't want to mess with cutting/modifying the track section to install an insulated outer-rail, you can place a 10-cent magnet on the trolley(s) and then a 25-cent reed-switch in the track bed on the approach to the station.  The reed-switch would then trigger the timer module to shut-off center-rail power via the relay for however many seconds.

OTOH, if you do use the insulated outer-rail method to trigger you may run into a so-called race condition which can create false/multiple triggers.  See if this makes sense.  The trolley arrives to the station section that has been modified with an insulated rail trigger.  The trolley triggers the relay which stops the trolley.  But the trolley is now sitting on the insulated rail.  So when center-rail power is restored, the trolley instantly re-triggers the timer and maybe jerks for a fraction of a second and then stops again!  Lather, rinse, repeat.  So maybe you cut an insulated rail section that is only 1" long (or whatever) so that the trolley triggers the timer but rolls by the 1" trigger section under its own momentum before stopping.  As you can see this technique is fraught with peril! 

So to dig further down the rabbit-hole, what you could do in this situation is use 2 timers; you could have the insulated rail section the same length as the stop section.  Both timers are triggered together but one is set to 10 second and the other is set to 15 seconds (or whatever).  Power is removed from the center-rail for 10 seconds...but the outer-rail trigger section is disconnected from the timer triggers for 15 seconds.  This gives the trolley 5 seconds to leave the station and roll out of the trigger section since the triggers have been disabled for 5 seconds when power is restored.  Timer modules are only a few bucks so not really much of a penalty.  The 2nd timer essentially duplicates the nichrome thermostatic switch delay in the 132 accessory.  That is, when the trolley leaves the station it takes several seconds for the nichrome switch to cool down which gives time for the trolley to leave the station without instantly re-triggering the stop.

Separately, if you go with the insulated outer-rail trigger you probably want to use a wall-wart to supply the 12V DC power for the timer modules.  The AC-to-DC converter module that Leo shows cannot be used as-is for most train transformer systems.  That is, it creates a "new" DC- output voltage that does not play well with the AC common in most layouts.  This has to do with the bridge-rectifier in the AC-to-DC voltage converter.  We can get into the technical details of mixing AC and DC commons if interested, but a 12V DC wall-wart is only about $2-3 on eBay.

you probably could use the timer from the 253 Block signal. It provided the same delay operation as the 132 stop station. 

Clete posted:

you probably could use the timer from the 253 Block signal. It provided the same delay operation as the 132 stop station. 

Does it use the same nichrome thermostatic switch?  If so, I'd think it would have the same voltage "leak by" that Dale says would not work for his MTH trolley.

The nice thing about the relay method is you could then choose to present 0 Volts to the center-rail to truly stop the trolley in its tracks...or some non-zero voltage that mechanically stops the trolley but also keeps the lights on so the passengers can safely load and unload.  I don't know which MTH trolley Dale has, but on the newer Protosound trolleys with speed-control there is a defined voltage range where the engine will not move but the electronics (e.g., the lights) will stay on.  

Or just replace the original style thermostatic switch assm. Sure sounds a lot easier!

Thanks for all the great input, guys.  The trolley I'm using is a 2005 MTH RailKing 30-2581 NFL Steelers Bump-n-Go Trolley.  It's pretty basic - no Protosound.  It really has to have 0 volts to stop, and I'm afraid the poor passengers are going to have to get off the trolley in the dark!   I think I'll get one of the relay circuit boards and then just play around with it, trying some of what y'all suggested.  For about 4 bucks, even if I can't get it to work the way I want, I'm not really out much...

Dale 

When I last "researched" the original Nichrome switch (e.g., in this thread) they were $25 or so, re-furbished, and potentially difficult to find.  Clearly a drop-in replacement would be the easiest, but my understanding is it nevertheless would not work in Dale's application because of the voltage "leak by" since the switch is really a ~100 ohm resistor when in the stopping mode.

I think it could be done for $5-10 using eBay modules (e.g., relay, timer, voltage regulator).  But it would require DIY'er persistence, wiring, and the like. 

There are many suitable timer relay modules that I think will do the trick.  In the video below, the station stop zone is the single track section with the white-paint.  This is just a proof of concept - a station stop zone would no doubt be much longer.  I didn't have a trolley to play with so just used a powered motorized truck (co-opted from a twin-motor diesel) with a bridge-rectifier to convert track AC to motor DC; the motor is locked-in-forward so to speak.  There is also a white LED on the truck to show when power is applied to motor.

In this example, the timer module shown above is set to Mode P-2, CL time of 7 sec, OP time of 3 sec.   Normally there is no track power in the station zone.  When trolley enters the stop zone, the timer module is triggered.  This starts a 7 second (CL) delay which is the station stop time; the relay is OFF.  Then the relay is ON for 3 seconds (OP) which powers the station zone so the trolley can leave the station and reach the powered track.

Note that if the station stop zone is too short and/or the trolley enters the station too quickly, it can coast through the unpowered station zone and reach the other side and continue on without stopping.

The key to this method is tying the DC common that powers the DC-timer-relay module to the AC common that powers the track.  

If there is any interest, I can provide additional details and comments.

Stan: What happens when the whistle is blown and the transformer puts out DC to the track? Will that not conflict with the DC common on your circuit?

That's an insightful question. 

Tying AC common and DC common together can seem like black magic or something untoward!  But here's what's going on.  Remember we are starting with two isolated circuits...the AC circuit which has the track power and the DC circuit which has the timer/relay power.  These two circuits are isolated because they are operating off separate transformers.  Hence they are not aware of each other's existence in an electrical sense.

As you know the term "circuit" itself implies a to-and-from.  Connecting one wire between two isolated circuits does not create a new circuit or electrical interaction because you only have a "to" and not a "from".  Hence the two circuits behave independently as if the other was not there...like two ships passing in the night.

So that's what we have when with the shared AC and DC commons.  The AC circuit can have a bell and/or whistle DC offset, it can drop to 0V on the track (for direction change) or even jump to 100V AC or whatever and blow up the engine, etc. … but the DC circuit is completely isolated and ignorant of this action!

I don't know if this made any sense at all but that's how I think of it...