Help need for timer

How hard would it be to change the track inside the tunnel? If you had an insulated outside rail, perhaps Gargraves or Atlas track, you would have the perfect occupancy detector. Then a simple light bulb would complete the system.

 

The ultimate solution would be to fix the cars so they don't uncouple.

We use occupancy detectors and signals on the club layout.  There are a couple of long tunnels, and as Elliot says, that's the cool way to detect it.

Track is old lionel o gauge and is not accessable to isolate the rails.

Should have thought of that 10 years ago.

Just looking for a timer that can be adjusted for a specific time.

Thanks

Why not just use something like the Atlas Snap Relay wired to a red/green signal at the tunnel entrance?  When the engine goes in, the magnet flips the Snap Relay to light the red light, and it doesn't go green until the last car exits and returns the signal to green by kicking the other coil.  Seems like a perfect application for this device.

 

If you're about to enter the tunnel and the signal is red, you have a problem.  If you really want to automate it, insulate a center rail for several track sections at the entrance to the tunnel and only energize it when the green lamp is lit.  You could really put the magnets side by side at the exit if you desire, the locomotive sets the red, the trailing car sets the green and re energizes the insulated track power.

 I just ordered them. I knew you would have the answer.

Very simple.

Thanks John..................

 

 

Your problem is a function of distance,not time. You can do it without a timer. Assuming the train runs only in one direction. On the tunnel entrance install 2 reed switches off set so that a magnet on the engine trips one and a magnet on the caboose trips the other. Then get 2 relays, a DPDT (relay 1) and a SPDT (relay 2). Engine magnet trips reed switch 1 which energizes relay 1 coil circuit.  Relay 1 coil circuit latches through one of it's C-NO contact sets in series with the C-NC contacts on relay 2.

 

So when the engine rolls over the it's reed switch relay 1 is latched. When the caboose runs over it's reed switch (2) it energizes coil 2 circuit which opens its contact set and breaks the latch on relay 1.

 

Use the second set of contacts on relay 1 to cut power off an insulated center rail section down the track.

 

When the train approaches the tunnel relay 1 is latched by engine. Power is off far down the track, If the caboose uncouples the train will stop on that section when it arrives. If the caboose is on the train it will energize relay 2 when it gets there which unlatches relay 1. Power will be on that distant section when the train arrives.

 

You can use 12 or 24VAC relays for this application. 24 volt ones will work off 18VAC. You can also use DC ones with a rectifier,but do not use a capacitor across the relay coil. You will need a separate transformer tap to work the relay circuit.

 

You can also use a twin coiled latch relay,which will have memory when power is shut off.

 

Dale H

Dale, the reason I suggested the reed switches at the exit of the tunnel is then you know the status.  If you have the switches at the entrance of the tunnel, you trip the "all clear" with the trailing car going in, but if it drops it in the tunnel, you don't have the indication. 

 

I don't think you accomplish the goal with the reed switches at the entrance of the tunnel.

 

John

 

A lot of ways to do it. The entrance and exit would be better for a block signal assuming you have enough room to deaden a track section down stream which would allow for automatic shut off.  

 

I never used the Atlas snap switches. Will they take continuos voltage if the train stopped on the reed switch? 

 

Dale H

Good input, Thanks.

I still am looking for an adjustable timer to trigger an alarm or light to alert me that part or all of the train is in the tunnel longer than xx seconds. It may have stalled or derailed without shorting out the fuse.

Thanks again.

John................

John

 

You can use these timers in some kind of circuit using the reed switch and relays. Not exactly sure what you want to accomplish.

 

www.jcstudiosinc.com/BlogShowT...=481&categoryId=

 

Dale H

The ones I wired I actually used DC with a home-brew CD system, a resistor and a cap.  That allowed a small current through them continuously, but a shot from the cap to switch them when first activated.  That may be the Achilles heel of the snap switch, I suspected that continuous power might be a problem when I installed them.

 

In this application, I suspect that stopping right on the reed switch is a pretty small chance, but it does exist.

 

If you do a block signal at the tunnel entrance, you'll have a steady indication whenever the trailing car has not left the tunnel after the engine has entered.  Are you looking for some other functionality?

 

 

I run about 8 trains at the same time and was hoping to find an audable warning for my problem trains. The block control is a great idea, but I still want an alarm to sound if the train does not clear the block in 10 or 20 seconds.
Thanks agian, you guys are wonderful.
John.

John

 

With the timer module I linked,with a relay contact you could drive warning lights,flashers,bell,buzzer or whatever. If you could make an insulated outside rail on the tunnel entrance and exit,you would not need at reed switch set up,I think. These need be only 1 track section long.

 

Dale H

I'm sure there are a number of ways to skin this cat.  If you don't have the reed switch, you're losing the sensing if the cars were dropped in the tunnel, which I thought was the object of the exercise.

 

If you look, he said he didn't want to use isolation of track sections.

I though he meant the tunnel itself because it was difficult to access.

 

Dale H

Dale, if you have no sensing in the tunnel, and you dispense with the reed switches, how do you find out that you left some cars in the tunnel?  That was the original purpose of this whole thread, I don't see how you're solving that issue.

 

You cant,I was addressing the timer circuit. Not clear if he wanted collision avoidance,a timer or both. The timer could be used with the 2 reed switch circuit collision avoidance described earlier. You would need to add an extra relay and timer module.

 

Dale H

I think the whole point of the timer was to alert him to the cars left in the tunnel.  I'm sure he doesn't want the timer alert going off every time the train goes through the tunnel, that would get old really fast!

Both of your solutions will deal with part of the train remaining in the tunnel. The other thing I want to do is alert me that the train has stalled or derailed in the tunnel. I would like it to be time adjustable to correspond to the length of the consist.

Great ideas thanks.

I think Dale is addressing the timing function.  My suggestion deals with indicating the train has not yet left the tunnel, and optionally switching off the power to one or more track sections at the entry of the tunnel to prevent a crash.  Dale was talking timers that can be connected to the signal supplied by the occupancy detection to provide whatever alert you desire that the situation has occurred.

 

The sticking point on timing is I'm assuming you do NOT want the alert if the train clears within the time period you've set.  I know how I'd do it, I'd use an electronic timer powered when the train enters the tunnel, and remove power when the entire train left.  If the train (or trailing cars) remains in the tunnel past the timer limit, it would sound the alert.

 

Truthfully, I'd make the timer fixed for the longest consist you'd be running, and add the block control section to prevent crashes in the tunnel as well.  I suspect adjusting the timer for the correct time each time you change the length of the consist will get old in a hurry.  Also, if you have more than one consist on the same track at the same time, are they both the same length?

 

I guess one question is, is this command or conventional?

You are correct with this

" I'm assuming you do NOT want the alert if the train clears within the time period you've set.  I know how I'd do it, I'd use an electronic timer powered when the train enters the tunnel, and remove power when the entire train left.  If the train (or trailing cars) remains in the tunnel past the timer limit, it would sound the alert.

Very old conventional. What do you suggest for the timer."

 I am running very old conventional.

 

What do suggest for the timer?

 

Thanks again. John..............

I don't have a ready reference to a canned timer that will do it, my approach is usually to "roll my own" with a 555 timer chip and whatever output device I want, be it a beeper or relay.  I'm sure Dale probably has an idea for an off-the shelf timer. 

 

The timer should be triggered by the train going into the tunnel, and if the time limit expires, it closes a relay that also goes through the NC contacts of the exit relay.  If the last car has exited, those contacts would be open and you'd get no alarm.  However, if those contacts are still closed, that's when the alarm would sound.

 

Running conventional, I'm assuming only one consist on the track, and you're just trying to eliminate the possibility of collisions with any cars left in the tunnel.  That being the case, I'm not sure why the alarm, just the switched power on the entry section would stop the train as it enters the tunnel and prevent the crash.  There's your "alarm".

 

I want to know if the train stalls or derails in the tunnel.

Thannks so much for all the time you have spent on this.

John............

Along with the circuit I described for collision avoidance,just add the use the Mars timer 32391 delay on make module. This has a calibrated dial that adjusts up to 8 minutes.It can be added to the circuit I described before for collision avoidance. In total you will need a 3pdt relay,a DPDT relay,a SPDT relay,a Mars timer module. Best to use 24VDC relays so you will need a bridge rectifier, 3 diodes for the relay coils,some hookup wire and maybe a condenser 1000uf 35 volt. You are looking at maybe $35 in parts to do it this way for the above parts.You will need an 18 volt AC power source to work the relays. Most any spare tap of a train transformer can be used.

 

You will also need an alarm. You could power most anything such as a Marx crossing bell or a light or block signal or both. If using the bell add a TVS across the leads if on the same circuit as the timer. You will also need 2 reed switches,2 magnets. No need to make insulated rails except for a center insulated rail down line to stop the train. Actually the system should work command or conventional assuming one direction operation.

 

Dale H

Thanks guys. You are great.

John.............