Planning a layout for my son

[DKS]

Really, a full-bore dual-cab system isn't much more complicated. Here it is, with all four switches:
 


The first switch controls the left half of the outer loop; the second controls the left half of the inner loop; the third controls the right half of the outer loop; and the fourth controls the right half of the inner loop. There are three sets of double insulated joiners at the crossovers, as noted by the pink dots.

The directional nature of the #6s simplifies things by allowing you to park a train on track two or three (counting from the outside) of the left half, as well as the sidings. Also, using center-off DPDTs lets you park a train on any other track.

[Dave V]

OK, that looks doable and not too complicated (I think).  I designed it such that one can switch the inside tracks without having to cross over to the outside loop, by including the passing siding.  So swapping trains is not going to be a frequent event, but I also didn't want to preclude it from possibility.  Jacob is not as satisfied as I am doing roundy-round; he's an operator.

Lee, what Atlas controllers do you have?  Are they DPDTs?  Thanks!

You all sure this isn't too complicated for an 8-year-old (or a 36-year-old)?

[DKS]

Dave, you can actually get by with just one switch. I will post an explanation in a few minutes.

[DKS]

Here's a one-switch solution. It's very similar to the earlier one with two switches, but the directional nature of the #6s makes life even simpler. Lucky you!



If you have one train on the outer loop (Cab A) and one on the inner loop (Cab B), here's how to swap them.

1. Set the switches on the inner loop to the passing siding (track 3), pull the inner train onto the siding, and set the switches against it to park it.

2. Throw the DPDT switch to change the inner loop from Cab B to Cab A.

3. Set the crossover switches to the crossover position, and pull the train on the outer loop onto the inner loop.

4. Park the train on track 2, beside the other train, and set the passing siding switches to face track 3.

5. Pull the train on track 3 onto the outer loop.

6. Set the crossover switches to the normal position, and throw the DPDT switch to change the inner loop back to Cab B.

7. Set the passing siding switches to face the parked train, and proceed.

You've now swapped the trains. Note that this works regardless of the two trains' respective direction of travel.

[Dave V]

Woohoo!  DKS does it again!

Cool.  That REALLY makes it easier for Jacob.

Now, can someone tell me what happens if, say, an 8-year-old forgets and runs a locomotive through the crossover from one cab to the next with both set to different speeds?  I assume it's bad, but does it also mean smoke and molten plastic?  Or does it mean confused loco stalls?  I assume there'd be a short that could potentially toast the circuit board in the engine...

[DKS]

Woohoo!  DKS does it again!

Cool.  That REALLY makes it easier for Jacob.

Now, can someone tell me what happens if, say, an 8-year-old forgets and runs a locomotive through the crossover from one cab to the next with both set to different speeds?  I assume it's bad, but does it also mean smoke and molten plastic?  Or does it mean confused loco stalls?  I assume there'd be a short that could potentially toast the circuit board in the engine...

It could be bad, yes, but there are ways to protect against it. For one thing, instead of using a DPDT switch, you could instead wire up a DPDT relay that works in conjunction with the crossover switches. When the switches are set to the normal route, the inner loop gets Cab B; when the crossovers are set to the crossover position, the inner loop is switched to Cab A.

This isn't as onerous as it sounds, but it does assume that the crossovers are remote-control. It also means all four switches will work together as one. Derailments could result if there's a train on the crossover when it's thrown, obviously, but that's not as bad as a loco crossing a mixed-cab boundary.

Additionally, I'd probably be tempted to wire the two switches for the passing siding (track 3) in tandem as well; otherwise, you'd have to put gaps in the middle of tracks 2 and 3 so that the power-routing properties of the switches will work properly.

[Dave V]

Hmm...  Was going to avoid remote switch control, at least at first.  I was going to run the wires down through the layout and have them available for a later date.  We'll just have to make sure Jacob knows not to cross over unless the DPDT is set properly.

[DKS]

You could rig up big bright red warning LEDs at the crossover gaps. They would be wired to light up only if the polarity of the two cabs are opposite one another; if they're the same polarity, the LED won't light up.

[Dave V]

Yep, could do that!

[Dave V]

David, thanks again for all of the help.  It's been invaluable.  Hopefully in the not too distant future Jacob and I could meet you at a gathering of the Asshats.

[davefoxx]

Dave,

If it matters at all, I say build this one with the full two-cab system.  I'm sure that Jacob will understand it very easily after playing with it for just a few minutes.  If you end up running it as you indicate, with one cab pretty much just running the outside loop and the other the inside loop, you won't really need to be switching blocks, if you're concerned about the complexity of controlling blocks.  I have a feeling that if you try to short cut this fairly simple block wiring, you and/or Jacob will be disappointed by how you must run the trains later.

Also, if and when you switch to DCC, all you will need to do is remove both cabs, replacing one with the DCC command station, and switch all blocks to that "cab."  Bang, instant DCC.

Interestingly, I still find it odd when people say DCC is complicated.  On a small layout such as this or a HCD layout, the DCC system can be much easier to wire.

Dave Foxx

[DKS]

Interestingly, I still find it odd when people say DCC is complicated.  On a small layout such as this or a HCD layout, the DCC system can be much easier to wire.

Yes, it is easier to wire. However, some consider the process of programming locos, acquisition and all the other shenanigans involved with operation to be daunting. Either system (block or DCC) involves some degree of complexity, and ultimately it boils down to personal preference as to which kind of complexity is tolerable.

[John]

Dave - is this layout in the same room with yours?   If so, the cost of DCC is $0 .. because you would need to spend the equivalent cost of decoders on power packs ..

If you can co-locate, just run a power feed from your DCC unit ..

[Dave V]

Daves...  I use DCC on the Juniata Division and it's not complicated at all.  Complexity is not the problem with doing DCC for Jacob (other than Dad having to install decoders for him).  Cost is.

John, no, this is not in the same room with my layout.  It's going in his room at the other end of the house.  There's hardly any room left in the bedroom my layout is in.  I see $90 in decoders + $50 for a basic system for Jacob's 3 locos versus $47 at Klein's for the second power pack we needed (his Amtrak set came with one).

I have to give this some more thought.  There's a sweet spot somewhere between operational flexibility and control complexity.

[mcjaco]

Dave,

If it matters at all, I say build this one with the full two-cab system.  I'm sure that Jacob will understand it very easily after playing with it for just a few minutes.  

I was eight when my Dad and I built our first HO setup on a 4x8.  We had two throttles and DPDT switches so I could park a train on the passing siding at the passenger station while the freight ran around.  I thought it looked terribly confusing when he started it, and helped him wire (I mostly watched  ), but after a few go rounds I figured it out.  I think if your son is really into this, he's at the age where he'll figure it out pretty quick.

Really love watching this project come together, much like Pud's project earlier this year.