N Scale Signal System Questions

[Kisatchie]

I'm a very long way from building a layout, but I was curious as to how to rig up a signaling system without using block detection. I have waaaay too many cars to even think about putting metal wheels w/resistors on them.

So I was wondering, could I have signals that are activated by the train engineer by flipping a fascia board switch as the train passes a signal, then having the engineer flip another switch as the train reaches the end of the block?

It seems like it would work, but I wonder if I'm overlooking something that would make the system inoperable for a big layout.


Hmm... who knows what
kind of thought processes
Kiz has...

[randgust]

I like to think I have the Worlds Dumbest Signal system.

My basic track plan is nothing more than a double-track oval wrapped on itself with one quirk - it narrows down to a single track for about six feet.

That six feet is why I need signals.  I have lights on the panel, that's not enough.  I rigged up signals at the entrance to the single-track block at all four entrances (I run bidirectional mains).   If you're walking around the layout, you can't see the panel from some spots anyway.

So that track has a simple reversing DPDT toggle switch the dispatcher sets for direction of travel.    With DC power and diodes, that sets all oncoming signals to red, and depending on the switch position, sets the one oncoming signal that's set for the switch to green.   Basic interlocking.  And it keeps you from piling up on a switch set against you.

There's no detection.   You pass a green signal, stays green.   I can live with that.

So I extended the same idea to the two mains.   There's a backdrop separating the two sections; an operator can't see through the wall.   Dispatcher sets direction of travel on the mains (east or west) with the same kind of reversing DPDT and the signals are at the backdrop entrances to the other side.   That way the operator on the other side has a clue which path is cleared by the dispatcher.   Again, no detection.

I've added some intermediate signals just for decoration, wired in again for direction of travel.  Mostly used so that if a trailing-point switch is set against you you get a red board, and if you get a yellow (now tricolor LEDs!) you've got a crossover set.

But the entire signal system is dispatcher controlled with three DPDT's, and a whole collection of switch contacts and diodes for interlocking.   

I'm now adding on second indications on some, with tricolor LED's I can now get a diverging clear (red over green)  and a restricted speed (red over yellow) indication depending on how some facing point turnouts are set.  I also want to add in the switches to the hidden yard so you get a diverging clear up on the main when the yard is set properly for you rather than studying the panel lights.

So it's a 'real' signal system in that it's completely  useful, but there's no complication from detection.   I can live with that one.

But yeah, I just love the look of lit signals, and now with the scale-sized LED's I'm completely and totally hooked.

[jagged ben]

Don't let resistor wheelsets be what stops you.   It's not that difficult to tweak a signal system so that the locomotives alone give you all the detection you need.  Also, if you run cabooses you just need to put resistor wheelsets on those and then you're pretty much set.  Same with a lighted passenger cars on the end of the train.

More generally...

If you're willing to not have signals "drop" to red when a train passes, then you can do a lot with switches, tortoise contacts, and diodes.  As described by Randy.   You can use this to make sure that routes are lined for your train, or just to setup nice looking photographs.  The simplest application is to rig some diodes to a tortoise contact and have the signals show which route of the turnout is lined up. 

If you want to have signals 'drop' realistically then you're really going to need detection. 

Randy, I'd be curious to see some diagrams of your setups.

[Kisatchie]

Don't let resistor wheelsets be what stops you.   It's not that difficult to tweak a signal system so that the locomotives alone give you all the detection you need.  Also, if you run cabooses you just need to put resistor wheelsets on those and then you're pretty much set....

That's a relief! I could do that. I'd rather put metal wheels on 78 cabooses than thousands of freight cars.


Hmm... Kiz is a greedy
pig... calls himself a
collector...

[randgust]

I've put Richmond Controls lighting systems (that do end markers and interior lights) on all my cabooses, which requires metal wheels.   Fully equipped with capacitors so steady-on.    I have some built on Kato frames with end-axles, and I have some with wiper pickups.    That seemed like a really good idea until I realized that those metal wheels in the caboose can raise hell in going through reversing loops.   I have to be really careful that the caboose wheels clear the main gaps before I flop-over polarity for exit, or BANG in DC-world.   I have occupancy detection on the hidden reverse loops so I can track progress, but now you have to have the reflexes of a cat to see the blocks clear and flip the polarity and track switches and stay in motion at the same time.  Kinda gave that part up.

So I now have a 'stop and proceed under restricted speed' rule since I went to metal caboose wheels.   First time you come to an abrupt stop, blow a breaker, and derail a 25-car train in a hidden yard, yeah, great idea!

[randgust]

The whole concept on the toggle-controlled signals is really simple, if you think about it.  The key is that you have to use a DC power supply so you can control everything with diodes.

Every signal logic input 'board' has two different 'feeds'.    'Normal', which is direction-of-travel facing, and 'Red Override' which means the direction of travel is set against you.

So each board has a 'red'  'green' and 'red override' feed.

The 'normal' may be fed through various switch contacts that may feed various contacts to either light up the red or green (or other indication) feeds to control the proper red or green indication.

The 'red override' is done by direction of travel only, it sets every signal to red that you are looking at.

The way you keep from inadvertently having the wrong feed light the wrong signal is by diode-blocking the feeds apart so that the red-override doesn't feed backward into the normal red  feed.   Hence, DC only.

So your DPDT throws the direction of travel over to 'normal feeds' in one direction with 'red override' in the other, or just the reverse of that.  You're not changing polarity, you're changing where the DC feed goes into the signal logic via the 'normal' or 'red override' side of each signal.

That worked for years with an all NJ-signal system and bulbs.   When I went to LED indications, suddenly I realized I got lucky with common-anode vs common-cathode design, because with the wrong LED's, now NOTHING would work at all.   And not all LED's are the same, but the ones I got from both Tomar and Miniatronics worked just fine.

[Jeff AKA St0rm]

That's a relief! I could do that. I'd rather put metal wheels on 78 cabooses than thousands of freight cars.


Hmm... Kiz is a greedy
pig... calls himself a
collector...

That being said you only need 1 metal wheel set per caboose to help cut down on cost.

[peteski]

That being said you only need 1 metal wheel set per caboose to help cut down on cost.

Make sure to put plenty of weights in the caboose and keep the detector wheelset impeccably clean.  Judging by what I read in the FVM Resistor Wheels thread in another section of this forum, the single-axle reliability might not be all that good.  When more cars in the train have one of those wheelsets, the detection reliability is dramatically increased.

[alhoop]

Randy, I'd be curious to see some diagrams of your setups.

I too would like to the diagrams. -

If they are the same as the ones that appeared years ago on the Atlas board,

 it was interesting following what Randy was doing.

Al

[Santa Fe Guy]

Make sure to put plenty of weights in the caboose and keep the detector wheelset impeccably clean.  Judging by what I read in the FVM Resistor Wheels thread in another section of this forum, the single-axle reliability might not be all that good.  When more cars in the train have one of those wheelsets, the detection reliability is dramatically increased.

Too true. Also if you go the detection route and have some short blocks that are detected and you have a train longer than that block the loco can be in one detected block and the caboose in another so you get a "no detection" on the track in the middle section if you only go the loco and caboose.
Just something to watch for.
I also love the simplicity of Randy's system. If I had known about that some years ago might have saved me a lot of dollars LOL.
Rod.

[Mastertech]

I have to chime in on my simple system, my signals are controlled by turnout position since that each block starts at passing sidings, it's great for running trains cause I can see witch way turnout is thrown by signal indication I know it's not prototypical but hey it works.

[Santa Fe Guy]

I have to chime in on my simple system, my signals are controlled by turnout position since that each block starts at passing sidings, it's great for running trains cause I can see witch way turnout is thrown by signal indication I know it's not prototypical but hey it works.

MY SFRSD operated this way for about 10 years and very well except when guys started to move from one town to another both blinded by the backdrop. You know what happens next.
Rod.

[eric220]

I'm also going the route of lights or resistors in the trailing car. I know that it will cause an occasional approach aspect to appear in the middle of a long train, but I don't think it will do any harm. Of course, we'll have to see how it works in practice.

Another option is optical detection. If you have several detectors per block, any one of which causes the block to report occupied, it would eliminate the need for detector wheel sets.

[bdennis]

If you go down the optical detection path, then, if you are using something like JMRI. You can add a delay to the optical detector so that once it has detected a train, JRMI can wait for x seconds before it goes back to a undetected state.

[GaryHinshaw]

Judging by what I read in the FVM Resistor Wheels thread in another section of this forum, the single-axle reliability might not be all that good.  When more cars in the train have one of those wheelsets, the detection reliability is dramatically increased.

A bit off topic for this thread but just for the record: after polishing the FVM treads, I am getting highly reliable detection with them.  Now I'm buying up FVM wheels right and left.