STAR WIRING for MTH DCS

Center rails should be insulated, so there is only one hot feed per block.  Do not insulate outer rails.  Do have occasional outside rail feeds, even without insulating outsiode rails, for better electrical distribution.  FYI, if you use Gargraves switches, most--BUT NOT ALL--have the three center rails insulated from each other.  If so, don't use insulated pin or you'll have a dead piece of center rail.  Some Gargraves switches have a metal piece underneath connecting the three center rials; on my layout, I remove these so that every switch ends 3 blocks.  Every one of the 70 blocks on my layout has a toggle switch, even those on main lines.

Thanks for your reply. Seems like the method I used but I thought I also isolated the outisde rail

Regards,

Charlie

You may have, but it's not advisable, since the wheels going over the insulating pin will keep making & breaking a circuit.  Do be aware that if you have non-derailing switches, you may inadvertently cut off ground flow.

RJR

Thanks again; will not isolate the ground / outside rails

RJR

When adding switches to your blocks; did you just switch the center rail ?

I have all Gargraves switches with no underneath wiring except 2 Ross and the Ross 4X yard switch.

Charlie

Only the center rail.  Do not switch the outside rail.

You might try just connecting your power feeds equidistant around the track before dividing it into blocks to see if you have a communication issue - many layouts do not. If you find that you do have an issue, you can then simply divide the track into blocks by using a Dremel with a thin cut-off wheel and cut the center rail about equidistant from each power feed.

RJR;

Thanks

Charlie

Richie C

Thanks . Will try before isolating the center rail since I have the track together and it did run at 10's before redoing a bit track last week.

Charlie

So I am in the midst of re-wiring my layouts. I read the threads about Star wiring and I am confused. I thought the idea was to have the signal travel out and back the same distance. If you isolate the power, but not the negative aren't you just going to run into the same issues? Also I am checking power as I go, and I have wired a switch into my siding but running the power through a toggle, and negative to the block terminal. It says engine not on track. It's a 8 foot siding with 1 feed. Makes no sense. It eventually find it, but really? It is isolated on both sides in and out. Not sure how this happening.

Thanks, JB

Early on with DCS. there were some issues reported with some toggle switches degrading the DCS signal. Really the only way to tell would be to take it out of the equation and see if there’s any improvement.

JB, regarding your siding, may I suggest that with the siding empty and powered on, pull in an active engine and issue a few commands (reverse engine, blow horn, bell, etc) and see if you get a consistent and proper response.  If not, it can be a connection problem such as a loose wire or even dirty wheels/track.  Another thought would be then to use that same engine and in the same manner to check signal strength with either the handheld or DCS app.  If it is low, and it is not connections, it could be the toggle as suggested above.  Finally, if the signal strength is high, it maybe a battery problem (if the engine is PS2).  And that would make sense especially if the engine had been sitting idle on the siding.  Again, you can check the battery strength with either the DCS app or the handheld remote.   As an aside, I also find that I get better performance if I wire both outside rails together with pigtails soldered together and then running that back to the terminal block still roughly maintaining the paired wire length.

Regarding your first question, I believe the purpose of star wiring within power blocks is to limit the length of track over which the outgoing DCS signal must travel.  Once received, I too believe that the signal finds the quickest return route which would likely be the paired wire.  So as electrically there is no need to isolate the outside rails, similarly, there is no need to isolate that path from a signal standpoint.  It may also provide an alternate path for the return signal if for some reason the return is missed via the main paired path.

Bob

@Dave_C posted:

Early on with DCS. there were some issues reported with some toggle switches degrading the DCS signal. Really the only way to tell would be to take it out of the equation and see if there’s any improvement.

Thanks, I will try that!

@Bob Golfs posted:

JB, regarding your siding, may I suggest that with the siding empty and powered on, pull in an active engine and issue a few commands (reverse engine, blow horn, bell, etc) and see if you get a consistent and proper response.  If not, it can be a connection problem such as a loose wire or even dirty wheels/track.  Another thought would be then to use that same engine and in the same manner to check signal strength with either the handheld or DCS app.  If it is low, and it is not connections, it could be the toggle as suggested above.  Finally, if the signal strength is high, it maybe a battery problem (if the engine is PS2).  And that would make sense especially if the engine had been sitting idle on the siding.  Again, you can check the battery strength with either the DCS app or the handheld remote.   As an aside, I also find that I get better performance if I wire both outside rails together with pigtails soldered together and then running that back to the terminal block still roughly maintaining the paired wire length.

Regarding your first question, I believe the purpose of star wiring within power blocks is to limit the length of track over which the outgoing DCS signal must travel.  Once received, I too believe that the signal finds the quickest return route which would likely be the paired wire.  So as electrically there is no need to isolate the outside rails, similarly, there is no need to isolate that path from a signal standpoint.  It may also provide an alternate path for the return signal if for some reason the return is missed via the main paired path.

Bob

Thank you for the explanation. I was kind of wondering if I had all the same negative wires on the same side anyway, and wondered if that could be an issue. JB

JB, not sure what your using for a turnout. Just make sure you power the turnouts switch machine off a separate power source. Not your track wiring.

An alternative to using a toggle switch for track power is to use the same toggle to control a relay. Run your paired wire and cut your center rail wire at some point and connect the ends to a relay. You can run lighter gauge wires to your toggle switch to control it. This way your track wiring is running more of a direct path from the terminal strip to the track block. I used Bosch like automotive relays. They have mounting tabs built in and will handle large gauge wires. You just need a seperate 12v dc supply for them.

You want to put some thought into all of this. But don’t overthink it or complicate it. I have an older layout. Blocked with buss wiring and wired with a common ground. There’s feeder wires in every 3 ft. section of Gargraves. Long blocks with multiple feeders. With  a little tweaking it runs fine. All 10’s. Denies almost every rule of how to wire for DCS. Use good quality wiring with a robust gauge if it’s a large layout. Solid connections and keep it simple. If you run track such as Gargraves or Ross. Connect the outside rails with a jumper wire unless you need them for signaling or non derailing. The most important thing. Is constantly test your track signal as you go along. Don’t move further ahead with the wiring till your satisfied with what you have done.