DCC - wiring my layout?

[Greg Elmassian]

Actually, on a budget, since she is running DCC, you can have the train enter the reversing loop, and while the train is still moving, flip the DPDT and the train will not even hiccup.

So I would not use a center off to keep the train moving, and a couple of LEDs at the 2 entrances to the reversing loop can indicate if that end of the loop is set for entry/exit. Put a red led on each side of the insulator on the same rail... if it lights then the polarity is not set right. Put a green led on one side of the insulator on rail A and the other lead on the other side of the insulator on rail B.

Green: ok to proceed, red, not ok...

simple and cheap.

Greg

 

[Neil Robinson]

Thanks guys, I can at least see how a short would occur.
Sarah Winfield

a) Do I put isolators on each rail?

Yes

b) Does it have to be each end? Could I not simply put the isolators in the center of that run of track?

Yes, you need a section of track longer than the longest train with a pair of isolators at each end

c) Could I put one isolator on one rail at one end and the other on the other rail at the other end?

No

d) Since putting isolators means there will be no power between them does it mean putting new connections into the track between each yellow isolator? (Subject to what you say about b) and c)) Presumably this is where DPDT switches come in?

Yes

 

[dunnyrail]

a) Do I put isolators on each rail?

Yes

EDITED BY JOND
b) Does it have to be each end? YES
Could I not simply put the isolators in the center of that run of track? NO

Yes, you need a section of track longer than the longest train with a pair of isolators at each end

c) Could I put one isolator on one rail at one end and the other on the other rail at the other end?

No

d) Since putting isolators means there will be no power between them does it mean putting new connections into the track between each yellow isolator? (Subject to what you say about b) and c)) Presumably this is where DPDT switches come in?

Yes

Sorry to be pedantic.

 

[Neil Robinson]

I have drawn this diagram based on Greg's ideas in post number 41 applied to the RHS of your track plan.

Note that with DCC it doesn't matter which way round you connect the leds.
Green means safe to proceed across the adjacent isolating gap in either direction, red means throw the DPDT switch before proceeding, thereby changing to green.

You could make track breaks by simply sawing through the rails halfway between sleepers provided the adjacent sleepers and rail fixings are in good condition. If the rails are prone to move (expand?) and touch a little araldite in the gap may be a good idea, just don't get any where it may foul the wheel flanges.

 

[dunnyrail]

I have drawn this diagram based on Greg's ideas in post number 41 applied to the RHS of your track plan.

Note that with DCC it doesn't matter which way round you connect the leds.
Green means safe to proceed across the adjacent isolating gap in either direction, red means throw the DPDT switch before proceeding, thereby changing to green.

You could make track breaks by simply sawing through the rails halfway between sleepers provided the adjacent sleepers and rail fixings are in good condition. If the rails are prone to move (expand?) and touch a little araldite in the gap may be a good idea, just don't get any where it may foul the wheel flanges.

View attachment 238267

Yes indeed what you propose is perfect, but DCC has moved the concept of that proposal on some. Plus you need to remember which way the Train is comming from. Ok so mount it near the loop and Left it is ok for that direction and right it is ok for that direction. But many operators just do not get that, how do I know? Long story but just accept it. Plus long term I believe that Sarah will perhaps want to run without dashing off to change switches for Electrics, she will have enough on changing points. Sorry not being contracending here, I do have regular Operators at my line and try to make things as easy as I can for them, a trick job at times! They have no issue with changing switches for electrics at all.

I atill think that for Sarah with her admitted lack of understanding on electrics a Reverce Loop Module will work so much better when she can afford them/it - question still needs an answer 1/2 or 3 with her plan?

 

[Neil Robinson]

I atill think that for Sarah with her admitted lack of understanding on electrics a Reverce Loop Module will work so much better when she can afford them/it - question still needs an answer 1/2 or 3 with her plan?

I agree, my posting was intended to be a short term relatively cheap solution until Sarah chooses to purchase reverse modules She may defer this as I suspect that she may not intend it to be operated by visitors and the reversing loops will not be in constant use as trains can bypass them.
In my opinion it would be wise to arrange for the isolating breaks to be arranged during early track laying to avoid short circuits even if it means that some sections are initially out of use

For full automation I suspect three modules in total may be needed for intensive operation. The LHS side track breaks in both rails on the LHS are shown below. I think this should allow for simultaneous operation on both of these LHS isolated sections in either direction.

 

[Greg Elmassian]

No you don't have to know which way the train is "comming" from... that is the beauty of DCC, which way the leads go to the track pickups is immaterial, since it is the DECODER that decides direction, not track polarity.

And the decoder selects direction based on the command, not polarity.

So in this case, 4 LEDs and 4 resistors and one switch will tell the operator if it is ok to "traverse" that "gap" in either direction, basically as the train approaches the cap from either direction, if you don't have green, flip the switch, could really not be much easier.

After the train has either fully entered or fully left the insulated section, the switch position may be changed.

Gosh, we give an easy answer with an autoreverser, too expensive, give a simple solution that costs virtually nothing and have to re-educate on DCC... well, we ARE trying to help Sarah...

Greg

 

[LGeoB]

Yes, you can get by with one autoreverser for more than one reverse loop as long as nothing can be in both loops at the same time.

I don't know what stuff costs over there, but autoreversers are inexpensive and easy here, but I don't want to argue the point I know will come up... here in the US everyone use the ones that are simple, sense the short and reverse.

Apparently there is a strong opinion over the pond that this is bad, causes issues and you need the more complex and expensive autoreversers that use sensors/switches/extra track sections.

$53 here https://tonystrains.com/product/dcc-specialties-psx-ar-power-shield-auto-reverser-circuit-breaker/

All the major clubs and everyone I know use these, they are the best, there are cheaper ones.

Greg

Agreed. I use Lenz devices to automatically switch and these detect the short circuit quickly enough.

Geoff

 

[Gavin Sowry]

Actually, on a budget, since she is running DCC, you can have the train enter the reversing loop, and while the train is still moving, flip the DPDT and the train will not even hiccup.

So I would not use a center off to keep the train moving, and a couple of LEDs at the 2 entrances to the reversing loop can indicate if that end of the loop is set for entry/exit. Put a red led on each side of the insulator on the same rail... if it lights then the polarity is not set right. Put a green led on one side of the insulator on rail A and the other lead on the other side of the insulator on rail B.

Green: ok to proceed, red, not ok...

simple and cheap.

Greg

I fully agree with your proposal Greg. Within budget, and comprehensible.

I have a similar approach to analogue with my balloon loop. My DPDT switch is located by my hand throw for the loop turnout.
Simple operating rule, the switch knob must always lay in the same direction as the points are set. Since the'main' line feeds the loop via the DPDT,
it is important that I know that the main is properly polarity set for trains exiting the loop. For this I have diode wired a signal, green for polarity set, and red for stop.

 

[Michael]

I am sure you are all trying hard to help Sarah but your complex track layout ideas and reverse loop solutions are fine for those with lots of experience but are they really suitable for someone new to DCC?

Personally I'm with Peter's post 7, but as she wants to continue with DCC, can't you suggest simple track layouts that she could upgrade later. Perhaps a nice long winding loop with a siding and a passing loop so she can operate trains in both directions. Once operational and she becomes more comfortable with DCC, she could then electrify the points before she starts thinking about reverse loops.

 

[JimmyB]

I glad that I decided NOT to have reversing loops in my layout, its not the complication, or the expense, it just takes the ease out of things. when i have advanced and have a running layout I may reconsider.

 

[dunnyrail]

No you don't have to know which way the train is "comming" from...
Greg

A common language divided by a big pond. I was refering to Analogue where it is important with a switched reverce loop to know where the train is comming from and when to switch the polarity.

As you say DCC does not give a hoot hence for Sarah going with DCC into Reverce Loops is the simplest solution once she can afford the relevent Reverce Loop Modules. Till then she can just have the tracks isolated and a few LGB Isolating Joiners are winging their way to her even now.

 

[Greg Elmassian]

In Sarah's case, I think DCC will simpler, especially when she eventually goes automated, the short-detection type of autoreversers only need 4 wires and can be located right at the gap.

In the picture above by Neil, I would agree for DC, but for DCC, I would put both tracks in the same reversing loop section and include the switch at the bottom, thus making it a bit longer.

In any case it will work, and can be easily implemented and inexpensively.

Go Sarah!

Greg

 

[Neil Robinson]

In the picture above by Neil, I would agree for DC, but for DCC, I would put both tracks in the same reversing loop section and include the switch at the bottom, thus making it a bit longer.
Greg

I'm quite new to DCC and am keen to learn more.
I'd thought of the above but suspected that it may hiccup if two trains were to depart simultaneously in opposite directions on the adjacent switched sections, especially if they had metal wheeled stock.

 

[Greg Elmassian]

Yes, but you would have this problem if you were running from one autoreverser/switch. I've been sticking to the minimum cost solution since Sarah has reinforced this several times.

On a small layout, I doubt seriously that she will be running 2 trains in opposite directions simultaneously.

Again, my assumptions are couched in simplicity and inexpensiveness, which don't always go hand in hand ha ha!

Greg

 

[dunnyrail]

Yes that will cause a problem as if the 2 locomotives are trying to change to change the loop polarity it will likely cause the system to shut down as in a short situation. Somewhat similar to using a long train with metal wheels pasing through the section. The contact of the wheels at one end and the other is enough to trip the reverce unit. We had a similar problem with the Ruschbahn in the early days where only one LGB Reverce unit was used, two trains on different Triangles would shut down the system to the complete surprise of all present. Problem was resolved when the LGB Unit finally gave up the ghost and Andy purchased 2 Massoth Modules, 1 for each reverce loop.

For the record the LGB unit was in a food container under the mountains with weather hitting the container all the time. Eventually the container broke down by UV Light and dampness got in killing the unit. I think we resolved the issue on the next ones by spraying the food containers Matt Black to block out the UV Light. But I would always suggest that the unit be indoors say a shed to keep out as much weather as possible. Inside a food container with the wire exit hole being Siliconed up to keep as much damp and ermsly germslies out is also a good practice.