Passing a train between two loops...

CoggesRailway

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Ok first I am an electrical dunce. I had an N gauge layout as a kid but my Dad wired it up and he is now past the point he can make any sense on much, especially something like this.

So my layout is esentially two parallel loops, two controllers. I have bought four points to allow transit between the two and also for the outer loop to act as a passing loop for a train parked on the inner.

I can see how I could wire a switch to allow each controller to power one loop and switch to control the other as well, excluding the other. But what would happen if through inevitable error a loco crosses from one controller to the other whilst they are both powered, in worst case with current flowing in opposite directions. Would something go pop? Some of my locos have decoders.

I have googled this and have not found much specific to this issue and what I have has befuddled me.
PS I know DCC would magic this away but my capital in the railway is going into track for the forseeable, so I need to solve this DC for now...

Ian
 

Gizzy

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What you could do is isolate your crossover, using insulating rail joiners and switch the section using DPDT switches.

If you supply each section with a DPDT switch, you can select the controller you require for each track section.

If this still confuses you, pm a diagram of your track to me and I'll draw the wiring and switches on it for you....
 

Tony

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Ian i speak only for me but i have 3 TEs and 2 lgb controlers all controling different parts of mine, Ive made it easyer in that everything goes in one direction except the sidings

i have 2 loops one at ground level and one at waste level each controled by one TE each then the sidings are controled by the third (are you still with me) The two lgb 5amp controlers are set and hardly ever adjust them they control the up and down ramps i have lots of different locos with different pick ups systems and they all happerly progress from one to the other,

The 3 problems i have are
1/ If a heavy train is on one loop and is getting caught by a faster lighter train say coming up the up ramp because ive increased the power to the heavy train the light one goes unrealisitly faster on the top loop
2/ if i send someing like my mallet with 18 coal wagons down the ramp and the bottom loop is set to slow when the loco gets there and slows the wagons dont
3/ after shunting in the sidings to get a train out i have to change the direct on the top loop which is fine as long as you remember to change it back be for the next express comes though
in short ive never blown anything up and all controllers locos etc are still working

You can wake up now
take a look at my videos
this one prob best
http://www.youtube.com/user/valeriejane61#p/a/u/0/CjfstebJPBk

Tony
 

CoggesRailway

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Thanks chaps....

Gizzy that sounds good. The catch is that for my larger locos the size of the insulated section to ensure all pickups are "in section" between the two loops may make the geometery tricky, but I think I could fix that.

If that sounds like I haven't understood... say! :D
 

Tony

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CoggesRailway said:
Thanks chaps....

Gizzy that sounds good. The catch is that for my larger locos the size of the insulated section to ensure all pickups are "in section" between the two loops may make the geometery tricky, but I think I could fix that.

If that sounds like I haven't understood... say! :D

Ian my sections are isolated by 1 pair of blocks so each section is right next to the next so for a short while a loco must be getting power from both and it doesnt seem to hurt anything
after a while you get used to it and it becomes second nature by the way my 3 TEs are controled off one remote

Tony
 

Gizzy

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CoggesRailway said:
Thanks chaps....

Gizzy that sounds good. The catch is that for my larger locos the size of the insulated section to ensure all pickups are "in section" between the two loops may make the geometery tricky, but I think I could fix that.

If that sounds like I haven't understood... say! :D
As long as each section is selected for the route your loco or train is moving along or onto, it shouldn't be a problem.
Send me a track plan and I'll mark it up with the wiring and switching for you....
 

C&S

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Ian,

I can't answer your question id detail about the liklihood of a DCC chip"popping" under Analogue conditions if the loco comes under two opposing controller settings, but I can outline what happens if I set up a similar situation on my all Analogue line (bear in mind this is with small four-wheeled locos).

If the two opposing controllers are set at about the same power setting the loco will get halfway across the tack join and then oscillate between the two sections.
 

Gizzy

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A picture paints a thousand words!

I've quickly knocked up this diagram for you.

You can see along the bottom, two controllers and a bank of DPDT centre off switches. I've only drawn the circuit for one of the switches but all are wired the same.

I've sectioned off the track using yellow for isolation in both rails.

I've used the Centre Off switches so you can completely switch off a section of track, and also so that any controller can control any section of track.

b3f2ef2ffeba4529a6bf4fb15d9c6339.jpg


By wiring as shown, you can't have both controllers powering the same section of track.

I would wire the switches so up was No 1 Controller, and down for the No 2 Controller. But it's your choice.

I've tried to show how the controller to swich is wired using purple for No 1 and green for No 2, just for clarity, but you can use any colour.

The switches would be commoned, or daisy chained on the input side, e.g. all the purple wires go to the same terminals on every switch; similarly the green wires would go to the other opposite input terminals.

I hope this helps explain things reasonably clearly....
 

Gizzy

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My last diagram was a little messy and constricted at the bottom, so I've redrawn just the controllers and switches.

I've drawn 4 DPDT centre off switches only, but you could quite add more later by 'daisy chaining' if required.

Note that the 3rd switch is selected for No 2 Controller, but the others are selected to No 1.

Hope this explains things better Ian....

39b681a6df7a438dad8f97055885c206.jpg
 

ntpntpntp

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Gizzy said:
I've used the Centre Off switches so you can completely switch off a section of track, and also so that any controller can control any section of track.

Classic "cab control" wiring, as used on all my N gauge layouts for the last 30 years or more. I'd certainly recommend it for analogue layouts with multiple controllers.

Of course, when you go DCC you just switch everything on (to the one input from the DCC command station) and leave it! also means you can still switch sections back over to DC if you need to run a non-chipped loco, with none of that dodgy "address zero" stuff!
 

dutchelm

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If you go for common return you can use single pole switches. Just join everything connected to either the inside or the outside rails together and connect to the same terminal on each controller. Cab control at its best!
 

dunnyrail

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Yes so go for common return. BUT if you use the same transformer and one of the Controllers is different to the other OOOPS SHORT. Best to do DPDT,

I recently helped a friend with a layout and we did full cab control on the layout using 4 controllers over 4 panels for a double track line with 2 terminal stations. Yes a lot of wiring in the panel and link wires for each controller. We used Rotary switches for this complex wiring. IT PERFORMS ALMOST AS WELL AS DCC.
JonD
 

CoggesRailway

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Thanks chaps and especially to Gizzy! That is SO kind to go to that trouble- I think I get it, but now with a diagram and some time I WILL be able to sort it. Thanks again. I will let you know progress!
 

ntpntpntp

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dunnyrail said:
Yes so go for common return. BUT if you use the same transformer and one of the Controllers is different to the other OOOPS SHORT. Best to do DPDT,
I agree - that's what I was taught many many years ago: that common return requires the controllers to be on independant circuits, ie. separate transformer secondaries. Therefore, on the basis that I wanted to allow for ANY possible future power source, I adopted DPDT as standard for all my layouts. OK so it's more wiring but if you're running one wire to a location it's just as easy to run two! For isolating sections at the ends of sidings I do use a single rail break and simple on/off switch.