Building a Cab Control Panel - guidance required

[nomisd]

After much vacillation, I am finally starting to think about building a control panel for my layout. I say layout but its really a two in one layout, see here and here for details. I spent an inordinately long amount of time deciding how to actually power this layout, DC or DCC. I have decided on DC, mainly because I already have a Gaugemaster TS controller and its all question of economics. So for better or worse that is what I am going for.

 

This of course now means that I have to build a control panel. It would seem that approach to take with all of this is Cab Control. With this in mind I have drawn the attached first go at it. At this point, I should point out that this (and wiring the track and point motors) is at the very edge of my a) knowledge and b) experience. I sort of get the principles of what I doing here but only just! I am not quite at looking at wire as being magical electric string but. I know that for some people reading this, some of the questions I have seem blindingly obvious but I have to admit that I am approaching this part of my project with more than a little trepidation.   

 

A couple of points of clarification before I get to my questions. Green is Cab A, blue is Cab B and purple is Cab A or Cab B. The numbers are points and the text in red are codes so I could identify how many sections I have. All track is Peco code 75 and all the points are electrofrog. Point 3 & 4 is a three way point, 5 and 6 is a double slip. will be using MTB MP1 for point motors. LS1 & 2 is in reality LS1 and 2 A and B as its a loco shed so will have isolated sections

 

So my initial question is my diagram correct so far?! A very rapid follow up to that is there are 26 (I think) sections on the plan, excluding the fiddle yards and loco shed as discussed above. I am correct in thinking that each one of these sections requires some sort of switch? The purple sections are the parts that required DPDT switches with everything else being controlled by SPDT switches?  

 

Thanks in advance for any guidance that you can offer.  

 

 

    

[Nigelcliffe]

It depends on a further detail of "how is this wired".   

 

The lowest wiring count, and probably the simplest to wire, would be "common return", which the Gaugemaster Twin will support.     Note that Common Return requires all controllers have independent transformer windings.  This is fine with a Gaugemaster Twin (because the internal transformer has two sets of windings), but you can't share one transformers/power supply over multiple controllers. 

 

With "common return", you declare one rail (eg. rail furthest from your operating position) as "common", and all the wires from that rail eventually join together. 
The other rail is switched,  so a wire from each section on that rail comes back to the control panel.  

 

See Gaugemaster's article on Common Return: 
https://www.gaugemasterretail.com/rightlines-article/layout-control-and-common-return.html

 

And, specifically the switch diagram at the end (Image from Gaugemaster's website): 

 

 

In the control panel, I'd use, Single Pole, Double-Throw, Centre-Off switches(*).    With those, you get three positions:  CabA, Off, CabB.   With that arrangement, any track can be controlled by either controller, and the wiring is identical throughout the panel.   (You might choose to operate certain lines mostly with A, or mostly with B).  

The centre (common) pin on the switch connects to the wire to/from the track.   
The CabA position pin connects to one of the wires from CabA Controller (ie. link all switches together, then to the Controller).
The CabB position pin connects to one of the wires from CabB Controller (link all switches together)

 

And the "Common Return" wire (above) goes to the other two terminals on the DC Controllers  (so it splits in two). 

 

(*  You could alternatively use rotary switches, use one pole, and three positions give you Cab A, Off, CabB.   )

 

Edited January 19 by Nigelcliffe

[Pete the Elaner]

Use plenty of different coloured wires. It is useful to document what is used for what. Even Nigel used 4 colours for his section diagram & that hopefully made it easier to understand (it did for me).

 

I also prefer to power sidings from switches rather the points. This gives several advantages:

I can do small shunt movements without having to set the points to power the siding. (Some like to provide power from points but I would rather see my live sections on a panel).

Isolating & re-feeding after points keeps the electrical sections very small. These are less likely to provide short due to feeding from the wrong place & easier to troubleshoot if anything does go wrong.

Rail joiners are weaknesses for electrical continuity. By isolating & re-feeding, you rely on them less. If you've ever seen a layout where the trains always slow in a certain area, poor rail joiners are the cause. This gets worse over time, especially if the track has been ballasted & weathered. Removing a point to fix it is a lot of work.

If you later choose to go DCC or sell the layout to somebody who wants DCC control, it is no problem: just close all your switches to make the track live.
The disadvantage is a bit more wiring. For me, this is outweighed by all the advantages.

[dasatcopthorne]

Nomisd.

 

I would agree wholeheartedly the previous posters. Common return is the way to go.

 

With your three 'areas' each complete are could be fed through a rotary switch, as above. Then take this feed through your isolation switches. That way, all three areas could be controlled by any of the three controllers.

 

May I also ask about ML1 and the other blue siding to its right (no number) If purple is in use, what can be done on ML1 using the blue contoller?

 

Common Return?  Don't worry, it's a piece of cake. Used it on all layouts since 1970s. And Pete is quite correct in describing how to change later to DCC

 

Good luck

 

Dave.

[nomisd]

Thanks for everyones input. I had sort of come to the conclusion that Common Return is the way forward with this.  

 

On 19/01/2024 at 14:11, dasatcopthorne said:

May I also ask about ML1 and the other blue siding to its right (no number) If purple is in use, what can be done on ML1 using the blue contoller?

 

 

That is a very good question. I think that answer is best explained with my reasoning behind it. In real life it was possible for industrial locos to work over BR metals. These locos were fitted with Railway Executive plates (which I believe came from a system that the GWR originally started) and were only allowed to work over very specific predetermined bits of line (IIRC these were listed in Local Sectional Appendices for each company who had registered locos). The shared sections are my take on this. So the its more of a case what Cab B can do on the BR section rather than what can be done on the non-shared sections at the same time as Cab B being "in control" of the section.

 

And you are correct, the original plan was incomplete. I have attached a v2. Interestingly, I actually went and looked at the track laid out on the board this weekend rather than drawing it from memory. It has slightly changed the actual layout. It has raised another  question, which may actually be a somewhat naive question but I shall ask it anyway (they do say there is no such thing as a stupid question after all).

 

I am somewhat confused by how power is supplied to points. What I mean is actual power feeds rather than the motors to control them. If we accept that relying on the rail joiner to supply the power then the power has to come from somewhere. Does this mean that each point will need to have droppers?  And a follow up to this if the answer is yes, where do these feeds go to? Or am I missing something very fundamental here?

 

 

 

 

 

 

 

 

 

 

[DCB]

I think there is scope for 5 areas of independent operation. Four locos /operators running / shunting simultaneously  I would arrange for all controllers to be able to access all areas, maybe like me you have an expensive controller with wander lead and some  old stuff without, makes sense to use the good one most of the time.   My terminus is wired with 6 sections fed from 3 sources and each SECTION  (Not Controller) has a multi pole rotary switch with red /green /Black/White   black being off. An "OFF" position is very useful, my main station does not have one.    Common return on a simple layout does simplify wiring and  allow single pole switches  but I would not use common again on anything complicated. I have no problems using fishplates for connection indoors but limit sections to five pairs of fishplates , that's six yards from the feed or 11 yards 33 feet 30 metres of plain track or maybe 5 points like 2 metres when feeding from the toe, its the number of fishplates which is critical    My Terminus panel is a row of six 4way rotary switch knobs poking through the baseboard framing with the switches behind on a sub panel which pull out when the knobs ae removed.   Main station rotaries poked through Hardboard. and the controllers are spread around the room.  4 of them can each operate over 90% of the layout so you can run a loco from just about anywhere to just about anywhere on any one of 4 controllers (The one with the wander lead usually)      see doodle black arrows feeds

[dasatcopthorne]

2 hours ago, DCB said:

I think there is scope for 5 areas of independent operation. Four locos /operators running / shunting simultaneously  I would arrange for all controllers to be able to access all areas, maybe like me you have an expensive controller with wander lead and some  old stuff without, makes sense to use the good one most of the time.   My terminus is wired with 6 sections fed from 3 sources and each SECTION  (Not Controller) has a multi pole rotary switch with red /green /Black/White   black being off. An "OFF" position is very useful, my main station does not have one.    Common return on a simple layout does simplify wiring and  allow single pole switches  but I would not use common again on anything complicated. I have no problems using fishplates for connection indoors but limit sections to five pairs of fishplates , that's six yards from the feed or 11 yards 33 feet 30 metres of plain track or maybe 5 points like 2 metres when feeding from the toe, its the number of fishplates which is critical    My Terminus panel is a row of six 4way rotary switch knobs poking through the baseboard framing with the switches behind on a sub panel which pull out when the knobs ae removed.   Main station rotaries poked through Hardboard. and the controllers are spread around the room.  4 of them can each operate over 90% of the layout so you can run a loco from just about anywhere to just about anywhere on any one of 4 controllers (The one with the wander lead usually)      see doodle black arrows feeds

 

5 areas of operation?

 

That probably means 5 people to make sense of the layout. (or two and a half people juggling with both hands).

 

And why would a 'complicated' layout not work with Common Return. Surely it would be simpler?

 

Dave.

Edited January 22 by dasatcopthorne

[Nigelcliffe]

If using Rotary Switches to select between controllers (common return or both poles), then make sure they are "break before make" type.    If the alternative "make before break" are used, the section switch puts both controllers onto a piece of track temporarily.   In DC running one probably gets away with that, but its not ideal (*).     Any reputable supplied can tell the difference and supply the correct type.   

 

 

One approach which may be worth considering is : 

  -   Rotary switches for the large coloured zones, so perhaps five of them, to choose between the controllers.   Rotary switches with common return layout wiring would permit up to twelve controllers on a standard switch.   Standard rotary switches have a little ring which the end-user adjusts to say how many positions the switch can be moved through, so a 12 position switch can be restricted to 2, 3, 4, etc.. as required.   

   -  simple on/off toggle switches for the individual sections within a coloured zone, to isolate locos as required.     

 

 

 

Wiring of turnouts depends on "which turnouts, from which maker".    There are lots of websites showing wiring of turnouts of different makers/models.    (Some are labelled as "wiring for DCC" - which is a wrong label, they are "wired properly for DC or DCC"  )

 

 

 

(* If the rotary is set to "CabA" - "Off" -  "CabB"   then it doesn't matter as the "off" will be temporarily connected to a Cab as the switch is moved, but that has no ill effects ).   

 

- Nigel

[DickF]

Having studied various comments and links can anyone confirm that my ancient H&M Duette is suitable for common return?   Control knobs are labelled Independent Outputs A and B respectively.

[melmerby]

This says yes:

https://handem.uk/pages/hammant-and-morgan-duette-instructions-in-3-languages

[kevinlms]

33 minutes ago, DickF said:

Having studied various comments and links can anyone confirm that my ancient H&M Duette is suitable for common return?   Control knobs are labelled Independent Outputs A and B respectively.

Yes, because the Duette has separate windings on the internal transformer, for the 2 controllers in the case.

 

There might be other reasons for upgrading to a better controller - mostly because they work MUCH better on modern motors.

[Brian]

Hi  The H&M Duette is suitable for Track common return.  What you cannot do is connect either of the uncontrolled outputs - 12v DC and 16v AC to the common return.

 

Reason is the Duette uses a dual wound transformer. One half of the output windings of the transformer feeds Track 1 controller and the 12v DC uncontrolled. The other half of the windings feed Track 2 controller and also the 16v AC uncontrolled.  If either of the uncontrolled outputs were to be connected to the track common return it would cause a short circuit!

 

The "Rule" of Common return is that whatever connects onto the common return wire it MUST be fed from totally separate transformer secondary windings or separate power supplies.

Edited March 12 by Brian
Addition text added

[DickF]

Thanks to both replies.  I was toying with using another (transformerless) controller fed from the DC outlet on a separate H&M Executive as well as using the H&M Executive, so 4 controllers overall with common return. That now appears to be a definite no no so I will have to abandon that (although I think somewhere I may possibly have an old transformer/rectifier that would be ok to use?)  You may have guessed that I am trying to minimise expenditure using as much as I can from a treasure trove from years ago uncovered in my loft when we recently downsized!

[melmerby]

2 hours ago, DickF said:

Thanks to both replies

Didn't look at my correct reply then?🙂

Edited March 13 by melmerby

[Jeremy Cumberland]

2 hours ago, DickF said:

Thanks to both replies.  I was toying with using another (transformerless) controller fed from the DC outlet on a separate H&M Executive as well as using the H&M Executive, so 4 controllers overall with common return. That now appears to be a definite no no so I will have to abandon that (although I think somewhere I may possibly have an old transformer/rectifier that would be ok to use?)  You may have guessed that I am trying to minimise expenditure using as much as I can from a treasure trove from years ago uncovered in my loft when we recently downsized!

Cab control comes in different forms. For a double track terminus, you're probably going to make every track section switchable between each of the controllers, which means having lots of selection switches, so there is a great benefit in having common return, to simplify the wiring.

 

However, in your original plan, you only actually wanted the purple zone to be switchable, with the green and blue zones having dedicated controllers. Here, there is little benefit in having common return for the entire layout; you could have common return within each of the zones, and a double pole selection switch for the purple zone. If you want individual track section switches for isolation or fault finding, these can be single pole on/off switches.

 

Since you are now talking about four controllers, your plans must be more complex, but if you still intend having a small number of relatively large zones, it's probably cheaper to keep the controllers you've got and only having common return with a zone, not across the entire layout.