A layout I’m working on currently has DC only power. It is divided up into districts which means it has gapped two rail blocks attached to some sort of block selector switch.
DCC doesn’t need blocks obviously (unless you are doing some sort of reverse loop) So you could just wire from block to block to block. Problem is if you install two sets of wires, and connect the blocks up to a common, then you just defeated your block.
I thought about using Diodes to restrict the current one way, but that doesn’t work either. The only thing I can think of is putting in a bipolar (current can go either way) 15Volt transistor at each block to act as a relay and attach the center leg of the transister back to a common block then back to the DCC/DC switch on the control panel.
Has anybody come up with a reasonable work around?
Assuming you have a two cab set up (lets call them Cab A and B) then by aligning all your DC blocks to Cab A essentially connects the entire layout.
You can install a 4PDT switch that when thrown to Position #1, will allow Power Pack A to be connected to Cab Buss A, and Power Pack B to Cab Buss B. When this switch is aligned to Position #2, both Cab B and Cab A will be connected to a single DCC feed.
…that make sense? That should cover everything but an auto reversing loop.
[2c]I run both DCC and DC on my layout.But not at the same time,I use a DPDT switch in my control pannel.When I use DCC I open all my blocks,except where I have non-dcc engines stored.I can also store DCC engines in my blocks,and turn them off.I have no problems so far.
I have 6-position rotary cab switches for each block (4 DC cabs/20 blocks). I just hooked in the DCC feed as cab 5, turned all the blocks to cab 5 and that was it, (there’s only one remaining DC cab for testing engines now).
Because I have a mix of engines (DC/DCC) and don’t have the bucks to convert all the DC engines to DCC I would like to wire up things like you are doing here.
However, I don’t have much experience with wiring and would appreciate if anyone could post some instructions as how to go about doing this.
My layout is divided into 16 blocks. Each block is connected to it’s own DPDT switch. When the switch is flipped up, the block is on DCC (Bachmann EZ-Command). When it’s flipped down, the block is on DC (using a MRC 280). All the DPDT’s are ‘center off’ types. All my blocks are wired in this way. This allows me to a DC loco in one set of blocks while running a DCC loco in another set of blocks without having to commit my DCC system to running a DC loco.
Either I don’t understand the ultimate goal of what you are trying to do, or you are taking a simple math 2+2 type problem and converting it into some sort of integral calculus.
As the others have said, to add DCC all you have to do is replace one of the DC controllers (or cabs) with a DCC command station (should be a matter of removing two wires from the DC control and connecting them to the DCC ouput). Flip all the block selectors to that cab where the DCC units is. Turn on the DCC unit and run the trains.
I don’t know how much more descriptive one can get with instructions than what is already been posted by the prior responders. The very root concept is that one gets a double pole - double toggle (DPDT) switch. This is the same type of switch used for DC direction control. Connect the tracks to the center poles
The current DC setup is for a yard which might have multiple engines. Therefor only one block is powered at a time. This is selected through a giant dial knob, so only one section is powered at once. This is a rather LARGE double yard that is restricted to one DC cab.
The hope would be to be able to power all blocks at once so that multiple cabs can take over with DCC. (We want to wear our yard operator out to early retirement before his pension kicks in! [;)])
QUOTE:" A layout I’m working on currently has DC only power. It is divided up into districts which means it has gapped two rail blocks attached to some sort of block selector switch."
“Some sort” of block selector makes a difference!
Atlas block selectors are SPST.
IFyou replacece these with DPDT toggles (center off) as Jeff Wimberly has, you can throw each and every block to either DC or DCC. I would add 16v bulbs to show indication.
IF ONEwants to be super cheap, use a single DPDT TO SELECT either power pack, and connect it to the layout, from the Center-two DPDT contacts. Then this is being used as a ‘TRANSFER SWITCH’.
Using a 3 or 4 pole DT $witch can show which power supply has been selected.
I would avoid any electrical contacts between the DC & DCC sources, or anything that could fry motors or circuit boards. You want everything EITHER /OR.
WHEN you go all DCC, blocks can become 'Power Districts.
If you have block control now, just use another position for DCC and when using DCC, switch it to it.
DCC and DC dont mix. I am going DCC but will use block control to separate blocks and regions, essential for signaling anyways so yer gonna block out the layout anyways.
Ok, I understand now. This is not a very common way to wire things (In fact I must say I’ve never seen or heard of a MR wired that way before). Normally each yard track where a locomotive was to sit would have a single SPST switch to it. That is the answer of one way to get around your delima. Connect a SPST switch between each of the rotary dials connections. So when all the switches are “on” than all the blocks are bridged. When they are “off” the blocks revert back to the rotary control.
If you don’t want to throw that many switches as your transistor idea you could get physical relays to do the job for you. One switch to activate as many 6PST relays as are needed to bridge the rotary positions.
I don’t know if your bi-polar transistor idea would work or not as the DCC signal itself is bi-polar and might pass right through to the DC side of the circuit. Perhaps if that was used inconjunction with a switch to disconnect the DC power supply.
oops I think you have a typo. Atlas block selectors are SPDT or they wouldn’t be able to “select”.
They work fine for making one cab a DCC controller. The only issue with common wire or common rail blocks is that the power supplies have to be isolated. There was a post here a couple years ago where the person was using the SPDT common wire/rail scheme. He was having very strange problems. We finally figured out that he was powering his DCC system with the AC output of his DC cab controller. This negated the isolated loops required for a “common” wire system. As soon as he got an independent power supply for the DCC system, everything worked as expected again.
If you put diodes in line with the DCC command booster (in the correct polarity, of course), wouldn’t this prevent you from frying it in case one of the switches failed and the DC voltage was on at the same time? Just wondering…