Hi there. I am wiring a DC layout and I have two loops with switching in towns and yards. I want each loop to have dual mainline cabs as well as a local cab in each town. I have DPDT centre off switches. How can I have the local cab not interfere with the mainline cabs and vice versa when powering a block? I should be able to have the blocks with an off position as well. Thanks steve
Steve,
A simple answer,for three cabs,is to use, rotary switches, instead of DPDT, The rotary,also has a off, position, hence,A,B,C, OFF…All your blocks, insulated on both rails…preferred,method instead of common rail,wiring…
Hope that helps,
Cheers,
Frank
When our club layout was put together in the 1980’s we had fourteen blocks and four throttles. We had to use rotary switches. A DPDT switch as only for a reversing loop.
Rich
While I would normally recommend Atlas selectors or DPDT switches for 2 cab, I have to agree with the rotary switch choice for 3 or more cabs.
I like common rail, having used it since the mid 80s with the same 2 MRC packs. No problems other than some rail joiner replacement.
Cost and availability makes having another simple solution a desirable option. Just use another set of DPDT switches in between the two circuits used for the main and the main itself. For each block to be powered with a local cab, this DPDT switch gives the option of whichever of the two main cabs is selected, while the other pole would select the local cab. Simple and cheap.
My Zone (town) Panel block power selector switches are 6PDT rotaries. Positions on the power selection deck are (clockwise from 10 o’clock):
- LEFT (a block designator)
- LOCAL (fixed or tethered cab)
- CTC (turns over control to Main Panel of MZL system)
- Portable (Plug connection for mainline ‘walk-along’ cab)
- RIGHT (a block designator)
- OFF (dead rail, no power)
The other pole is used to power indicators on the adjacent Zone panels and the Main panel when they are selected.
I use a modified MZL system, so one rotary selects power for a ‘tree’ of power sections that usually runs all the way through the zone. If the next panel over selects this panel LEFT or RIGHT the entire ‘tree’ is added end-on to that panel’s power selector’s control. It’s possible to orbit a loop by selecting one cab on one zone panel and setting the rotaries on every other panel to LEFT or RIGHT. You can also set up two conflicting routes on single track, then control which train does what at the meet station by throwing switch points. The train which approaches a trailing point turnout set against it will come to a rather clunky stop thanks to the auto-stop circuit built into the system (two resistors, one diode - CHEEP!)
Or, if I just want to run in ‘display’ mode to entertain mundane visitors, I simply set everything to CTC, adjourn to the Main Panel and run the whole railroad from there. (The Main Panel has two cabs and uses DPDT center-off selectors labeled CAB A - OFF - CAB B. The second pole powers an indicator at the Zone panel when a cab is selected at the CTC panel.)
I will concede immediately that the wiring is complex - more so because of the indicators - but the controls are much simpler than the traditional selector switch for every block. Most of the
Thanks to all, I was thinking this way. Each block would have two dpdt centre off switches-one for MAIN Cab A and MAIN Cab B, the other for MAIN and LOCAL- both with centre off. I am confused on how to wire this.Thanks ahead of time steve
steve,
I’ll do my best. I’m not showing both rails of the track. Each long line is a DPDT switch. Because of how MR formats the forum, I can’t connect each level of switching, but trust that there is a connection down from the Main level and down from the Track level. You have a power pack at these three locations: Local, Main A, and Main B.
Track
Main ________________________________Local
Main A Main B
Steve,
The way Mike is trying to tell you how to do it is correct, in fact if you remember to turn one of the DPDT’s off, you should be able to go any where on the layout,with any of the three cabs, you would have to daisy chain the center,two terminals,the ones that go to the blocks to have that work… It would be much easier, with a diagram to show you,sorry, but I can’t do that at the moment,cam is broke,
Cheers,
Frank
Steve,
Correction;;; The daisy chain I mentioned,won’t work to the blocks, must have been a fantasy moment,
Frank
thanks to all, What I am understanding from Mike’s post is that I would not be able to switch locally if a mainline train comes through either on Cab A or B- I would have to wait for it to pass for me to resume switching. Also I will need to insulate both rails at the ends of the local area and then daisy chain the common rail wire from the main cabs to the next local block so that my local transformer does not carry into the next local block of tracks. (I know- bite the bullet and switch to DCC lol)
Sc&vm,
It would be so much simpler, with rotary switch’s, They are not that much money from a electronic supply house, or surplus, outlet.
Cheers,
Frank
If everything at that location is wired as one block, yes, you would have to wait until the train on the main clears. This presumes you have some way to shut off power to the sidings/other tracks to hold your local switcher while trains move through.
But you should have more than one block. There should be, at a minimum, a block for the main and a block for the siding. Depending on the complexity of the track, you may have additional blocks.
So long as the main is on a block separate from the rest of the local traffic, you will be able to run trains through with it while still switching on the rest of the track on the other block(s) there.
Hello, I am curious about this switch. What is it called? I guess I do not use common rail. Many thanks Steve
I am running four loops each with its own dedicated cab by utilizing two dual cab controllers. I only need the DPDT switches to control the sidings off of each loop. An extra single cab controller can be had for next to nothing if you choose to go that route.
Witch Switch? The one I showed was a 2 pole 4 position switch. Details not found at the other end of the cat, will be found in the link that I gave you just above the switch pictch.
For this switch (called a slide switch) you would use one for each block, the common side would go to the tracks for each particular block, while the rest of the terminals are wired to one of four power packs. And the best part is these switches area bout $1.00 each.
If you will use a single wire system with a common return, you would tie all of the RIGHT outputs from the transformers together and run them to a common rail. On layout of LION the LEFT rail is common, and the RIGHT rail is power. +vdc moves train forward, -vdc moves train backward. LION ignorse that. Him puts +10v regulated DC on right rail, all trains move forward. Is no reverse: Subway trains do not go backwards. LION could tell ewe more about LION but that was not part of your question. It would confuse you. LION does not want to confuse you. But if LION did want to confuse ewe, ewe would be easier to catch and eat.
ROAR
Thank you LION. I thought you and the ewe would lie down (not be eaten), and swords will plough the earth? I ordered 30 of these in bulk (45 cents each) with the link you gave. I will give them a go. I have about 40 toggle switches so I may try a combination of these on the control panel.
Previous advice is right on - use a rotary switch.
LION has used rotary switches, toggle switches, and slide switches, but the ones that I liked best were ganged push type slide switches, press one, it releases the other. But then the LION always over built his Block Control, what with six throttles, when he only had one LION.
Automatic control is looking better and better on my line.
ROAR