Skip to main content

I am starting my first O scale layout this summer. The first town will be a pair of 3x6 feet long sections, making a total scene of 3x12 feet. I will be using Gargraves track, and it is divided into five blocks.

Question: when wiring block control with 3-rail track, is it customary to only block/insulate the center rail and leave all the outside rails connected as a common return? Or do you insulate all three rails at the ends of each block?

Question: some of the blocks are interrupted by switches or crossings so I will need multiple feeders in each block to get power throughout the block. For sections this small, will that mess up the MTH DCS system's "star wiring" requirement?



Images (1)
  • Layout block wiring diagram
Original Post

Replies sorted oldest to newest

For clarity why 5 blocks in such a small layout?  Be aware your outside rails are not contiguous, turnouts and your cross over break that up.

If you wish to create block only the center rail need by insulated.  As far as star wiring, someone with prior experience will likely weigh in, I have no experience with MTH control systems.

Just insulate the center rail.

My layout is wired with both common ground wiring and a bit of star wiring. Performance is the same as far as track signal. All 10’s. All my trackage is Gargraves. Feeders on every 3 foot section with no insulating pins. Totally against the rules of DCS. I’ve always felt the key to DCS is to use quality wire in an uncomplicated simple form.  DCS out to a terminal strip and from there to the track. 12 gauge buss with 14 gauge feeders. It seems heavy duty but there’s nothing wrong in overkill doing something you only want to do once. On your switching layout. I think 14 gauge with 16 gauge feeders is fine if you opt for buss wiring or even the star pattern. I used mostly quality automotive wire seeing it was available in a multitude of colors.

As far as what to do with the breakage in rail with turnouts. I soldered 18 solid gauge wires to every rail that looked like I might need at some point. I just found the solid gauge was easier to work with seeing I pre soldered them at the bench to the underside of the rails. Then attached them accordingly to the proper buss or feeder nearby. No need to run a paired wire to each rail of the turnout. If you by the Ross ready switches. The rails are jumpered with a metal strip. I prefer to wire my own and use the rail isolation built into the switch to isolate sidings and such.

My best advice as you lay track. Constantly test as you go along. If you have an issue with your track signal. Stop right there and don’t move forward till you correct it.

If you intend to kill the track power on your sidings. You can simply use a toggle switch to route the track power. I think a better approach is to run the center rail wiring through a relay. Depending on where you place everything. You will have a much shorter wiring run. Your run from the terminal block to the track is pretty much uninterrupted in more of a straight run. You will just have a break in the wire where it attaches to the relay. You can then use lighter gauge wire to control the relay either with a toggle switch or an AIU.

Again maybe overkill as far as amp rating.  I tend to use good sized relays that easily except 14 to 16 gauge wires. I like the Bosch style that have a mounting bracket.

@BenLMaggi posted:

Thank you all. I didn't know if having contiguous outside rails would mess up DCS.

As for the number of blocks, it makes it easier to park/store engines on the layout if I want without them taking off.

All roughly 500 feet of my layout track has common outside rails, DCS works just fine here.

All my yard tracks do have separate power switching, that's why I use the DCS-RC Perpetual Barking Watchdog Generator for those tracks.

Add Reply


OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)

Link copied to your clipboard.