Trouble shooting 2 Cab wiring issue

[Engauge18]

Hello All,
New to the forum.
Have built up the 'famed' Gulf Summit & Susquehanna Lines' railroad from the Atlas Nine N Scale Railroads book (N-109). For those not familiar, this is an old book, first published in the 70s. It's all analog wiring and code 80 track. It's a cookie cutter bench work design that has two separate railroads each with double track. It can run 4 locos simultaneously and independently, all in 4'x6'.
I built my version of this on a tilt table frame.
Question for the group: having trouble writing the second cab on the main line. The upper level has no issues with running 2 locos, it's the lower level that gives the issue.
The wiring diagram calls for sending a lead from one DC terminal on each cab to the main line 'C1'. When i do this though, only the second cab can run a loco.
I tested each cab and loco separately and they with fine. It's something in how I'm connecting the two cabs.
Thank you for your help!

 

[Iron Horseman]

It can run 4 locos simultaneously and independently, all in 4'x6'.

It looks like you are using Atlas block cab selectors. They can only select 2 cabs, so unless you are using three of them for each block I don't understand how this is possible.

The upper level has no issues with running 2 locos,

By the upper loop you mean the double track figure 8? And do you mean that one train is running on each track controlled by a separate controller, such that one can stop and even reverse while the other continues on.

it's the lower level that gives the issue.
The wiring diagram calls for sending a lead from one DC terminal on each cab to the main line 'C1'. When i do this though, only the second cab can run a loco.
I tested each cab and loco separately and they with fine. It's something in how I'm connecting the two cabs.

I also see from the photos that you are using two power controllers one that itself has two throttles. Make certain you are using the "common" from that throttle to the common of the track.

I cannot find C1 on the diagram, but following the "common" rail I see a problem with the diagram provided. On the "lower level" through the yard notice that the common rail is the inside rail. Follow that rail all around the bottom and it is all the same. Now take the turnout and go into the bottom loop of the figure 8. Same thing, the inside rail is common. BUT now go through the crossing, and notice that the inside rail becomes the outside rail. Then notice that they have an insulator on the outside rail. That is not correct. In the top part of the figure-8 the outside rail is the common. I believe if you flip that insulated joiner to the other rail -- as image below -- things should work fine.

Also note that the outside track on the upper figure 8 loop is a reversing section. Cannot see your whole control panel but that will require a special controller for that section.

 

[MikeGTW]

There is a reversing section and you need a atlas controller #220 for that And that one insulator is on wrong side as Horseman says
As for common there is not one for DC Either connection on the throttle will work It looks like it's wired for common rail So the one
mrc tech 2 dual power 2800 has two transformers in it so will be fine for common rail
My question how can you use three throttles that takes a lot more wireing and not easy to do Maybe using a rotary switch
We need some more info

 

[MikeGTW]

It looks like you are using Atlas block cab selectors. They can only select 2 cabs, so unless you are using three of them for each block I don't understand how this is possible.
I had to go and look at the wireing for those selectors and it could be done with just two of them kind of in series But why??

http://download.atlasrr.com/pdf/Item220Instructions.pdf

 

[Engauge18]

It looks like you are using Atlas block cab selectors. They can only select 2 cabs, so unless you are using three of them for each block I don't understand how this is possible.

By the upper loop you mean the double track figure 8? And do you mean that one train is running on each track controlled by a separate controller, such that one can stop and even reverse while the other continues on.


I also see from the photos that you are using two power controllers one that itself has two throttles. Make certain you are using the "common" from that throttle to the common of the track.

I cannot find C1 on the diagram, but following the "common" rail I see a problem with the diagram provided. On the "lower level" through the yard notice that the common rail is the inside rail. Follow that rail all around the bottom and it is all the same. Now take the turnout and go into the bottom loop of the figure 8. Same thing, the inside rail is common. BUT now go through the crossing, and notice that the inside rail becomes the outside rail. Then notice that they have an insulator on the outside rail. That is not correct. In the top part of the figure-8 the outside rail is common. I believe if you flip that insulated joiner to the other rail -- as image below -- things should work fine.
View attachment 151189

Also note that the outside track on the upper figure 8 loop is a reversing section. Cannot see your whole control panel but that will require a special controller for that section.

Than you so much for the detailed reply.
Attaching the full schematic and wiring diagram.

Yes, by upper level, meant the figure 8.
The lower level is the irregular loop.

All insulating joiners were placed and each sector has power.

The upper level (figure 8) runs a it should, including the reversing loop and two independent loco operation. It's just on the lower level that has this weird issue.

Also, i since switched out the double cab. Now have two single cabs.

I think I'm just missing one small detail about how to connect the second cab.

I think I'm misreading the wiring diagram on that one part.

Thank you again!

 

[MikeGTW]

Your jpg 226 now shows that single insulater on the correct side
And the wiring diag looks to be correct but they show four cabs
One controller for the reverse section
and that one selector for the interchange in series with another on so can switch between three cabs
That dual cab controller was fine it's made for common rail wiring

 

[MikeGTW]

Question are you wanting to set this up just like they show it If so then if you have the two single cabs and the dual one You can do just like they show If you alter it to two cabs or three that changes things

 

[Engauge18]

Thank you guys.
Yep, following the diagram as far as electronics are concerned. (Made some mods to the bench work).

I split the control panel. The upper level has its own panel (2 cabs, the reverse loop controller, the two selectors and related switches)

Have two kids and put them on opposite sides of the table to minimize fighting.
The control panel i showed in one of the other pics is for the lower level only.

The two control panels are linked via port terminals.

 

[MikeGTW]

OK sounds like you are close upper level works with the two cabs The controller is connecting one side of each output for you {common rail}
You can use the dual cab by itself for the lower level Just connect one side of each out put {2} together and that goes to C1 all C1 are connected together that mrc 2800 will work with common rail
Then the outputs from the two dc go to the selectors for cab control It should work just like the upper level just without using a atlas controller
If you wanted to and it is not needed at all you could use a second controller on the lower level To me waste of money since really not needed
Just make sure all common are tied together for upper and lower

 

[MikeGTW]

I forgot two kids interested in trains hope you can keep them interested so no fighting

 

[Iron Horseman]

Attaching the full schematic and wiring diagram.

That is interesting. I have never seen that done before (at least not in an Atlas plan). I'll have to study it a bit. Now I see how the two trains per level was being accomplished. That happens when a train transfers from the lower to the upper loop? Do you have to synchronize throttle settings?

The upper level (figure 8) runs a it should, including the reversing loop and two independent loco operation. It's just on the lower level that has this weird issue.

Yeah, I did read that you said that before, but couldn't find anything strange in the lower part so I thought it might be feed through somehow. With the new wiring diagram I'll look at it again with new eyes. Also with just a brief glance, I did notice blocks 25 and 26 cover the crossovers. What year was this book published? It almost looks like it is wired for hot joints on the crossovers, which I didn't think have existed since the 1950s.

Also, i since switched out the double cab. Now have two single cabs.

That removes one more variable.

I think I'm just missing one small detail about how to connect the second cab.

I think I'm misreading the wiring diagram on that one part.

I'll study it a bit over lunch with a new "outlook" and see if I can find something else.

 

[Iron Horseman]

Your jpg 226 now shows that single insulater on the correct side

That is really interesting they have it shown differently in the two diagrams. I guess it is a good thing it is shown on the correct side on the wiriing diagram.

 

[MikeGTW]

That MRC 2800 is made for common rail wireing It is fine as long as it's used correctly

Here's a link just in case maybe I'm wrong Page 2 5th paragraph
and don't know why two different diag but the 266 jpg is correct

https://www.modelrectifier.com/v/vspfiles/resources/dc-ac/Tech 2 2800 AF115.pdf

 

[Iron Horseman]

it's the lower level that gives the issue.
The wiring diagram calls for sending a lead from one DC terminal on each cab to the main line 'C1'. When i do this though, only the second cab can run a loco.
I tested each cab and loco separately and they with fine. It's something in how I'm connecting the two cabs.

Ok, backing up to this point. I'm going to ask some questions and make some suggestions that are probably trivial and you have already tried but bear with me.

1. When you say the second cab can run a loco. Do you mean the cab 2 (CAB B in the diagram) power pack can run a loco around both tracks of the bottom loop through all the blocks 1-15, and through the crossovers, and down the yard tracks?
1a. Does that also apply to the Interchanges 31-34?
2. When C1 is not connected to the first cab, what does it run? Anything? I would expect not as only one power pack terminal is connected, correct?
3. When you do connect C1 to the first cab, does the second cab keep running or does it stop? Theoretically the second cab should not be effected.
4. Now when you switch all the controls up to the CAB A position, the 1st power pack still doesn't do anything?
5. Then when you switch all the controls back to the original position for CAB B, and swap the two power packs then it works fine again, proving it is not the power pack? Sounded to me like you already tried that too.
6. In any of these non-working scenarios, have you moved the locomotive around to each block such that you know that ALL of the lower level blocks for CAB A are dead?
7. How old are these Atlas Selector units?

Assuming all that is true. The only thing I can think of is that the first power supply wire, not to C1, but rather to the selector bank is broken internally somewhere or the contact on the first selector isn't making a connection. My suggestion would be to get a new wire and run it from the first power supply over to the output for selector 14. Change 14 selector to the CAB A position and that should feed power backwards into the selector blocks. That will tell us if there is an issue with that first selector (1-4) input or not.

Beyond that I am thinking we need a volt meter and alligator jumpers to diagnose what is going on.

 

[MikeGTW]

Good advice from The Horseman I would only add double check your wireing I think something is not connected right If you wire it accoding to the diagram it will work I had one layout with 6 cabs on it
And you say one cab then the second give them the letter like in the diagram A B C or D
And like stated a meter or test light so you can follow the circuits It's probably something easy to fix

Lets hope the OP comes back and let use know if fixed

 

[Engauge18]

Hello All,
Thank you so much for your time and energy on my issue.
Had to deal with a major work deadline, but am back now.

To go through some of the questions:
This layout, N109 is from 1986.
It supports 4 locos independently; 2 on the upper level (Cab C and Cab D) and 2 on the lower (Cab A and Cab B).

At the moment, here's what's happening:
If Cab B is not turned on (meaning the power switch is 'off'), somehow, it can still impact Cab A. For example, if I want to reverse directions, I have to set reverse on both Cab A and Cab B to the same direction - even though Cab B is powered off!

Additionally, running Cab B can send power to both lines of track, even though the selectors are pointing the inner loop to Cab A and outer loop to Cab B.

I had a 45" call with a gentleman from Atlas yesterday morning and we talked through some of the steps. All the selectors were purchased as NIB from eBay sellers. (I don't mind used track, but figured electrics should be new). We went through the placement of insulator joiners and terminal joiners (outer rail) and the common rail terminal joiners (inner rail) as per the diagram. We then did a couple other tests. He believes it could be a bad selector unit and is going to have Atlas mail a replacement.

My plan, per his instruction, is to remove the first selector and then put another selector in that place and methodically test it. If that solves the issue, then it was a bad selector.

All sections of track, upper and lower level, sidings, yard, etc - all have power. The upper level has no issues; the reversing loop works as it should.

As an FYI, to answer the other questions: the Selectors for 31-34 feed the two ramps (two per ramp). If sending one loco down one ramp, another loco must be ascending the opposite ramp. It makes the operation more interesting and challenging as the movements need to be coordinated and switches thrown at the proper time. The selectors on these 4 sections allow either a lower cab (A or B) or an upper cab (C or D) to control said ramp.

Thanks again all - will keep you posted over time.

Take care and happy modeling!

 

[MikeGTW]

Yep if you have a bad selector then it will back feed to the other throttle That's one reason I never used them seems like I've heard that before
I only ever used toggle switches

But follow the guy from atlas and it will eventually work

 

[Iron Horseman]

At the moment, here's what's happening:
If Cab B is not turned on (meaning the power switch is 'off'), somehow, it can still impact Cab A. For example, if I want to reverse directions, I have to set reverse on both Cab A and Cab B to the same direction - even though Cab B is powered off!

That has to be common rail feedback somehow. Just curious as you have an action plan. But what does it do when it doesn't reverse direction - short or just nothing?

 

[Engauge18]

That has to be common rail feedback somehow. Just curious as you have an action plan. But what does it do when it doesn't reverse direction - short or just nothing?

Best thing i could do was make a short video to show the problem. It's so bizarre, and doesn't occur on the upper level at all, only the lower level.

I swapped out the original selector for the new one and the problem remains.

I think you are right, it must be a feedback from the common rail.

Thank you again for your time!

 

[MikeGTW]

I have a question You replaced that first selector that controls blocks 1-4 It looks like it is connected to the rest of the selectors 5-13 So can you just isolate that one selector for 1-4 nothing else connected and see if it still behaves like that It could be one of the other ones with an internal short Don't have any power from powerpacks A & B feeding anything else and just to be sure disconnect the common from C2 on the controller
I see your using block 9 Just use 1-4 nothing else