Frustration: 3 hours to locate a simple short!
3 of my 9 circuit breakers (CB) was 'shorting' (they are all on the same 'booster')
Besides 'on/off' toggles 'leaving' from each CB, I, also, have toggles along the facia to turn power 'on/off' to different tracks.
In the 'past' I had a short in the Seattle's yard where a turnout was shorting due to a 'frog'.
I started by turning off toggles to all the tracks in the yard but nada.
I turned off the 'main' toggle to Seattle's yard on the old 'control board' and the short disappeared.
OK, I surmise the problem is in the Seattle's yard.
After extension checking I could find no problems so I routed the D1 (Seattle) CB to a spare CB.
Continues on 3rd picture.
Previously, I had trouble with shorts with all these turnouts but they checked out OK.
I connected the spare CB to D1 and all was working well so I figure the CB went 'bad'. I used alligator clips for temporary 'checks'.
One 'booster' goes to 3 blocks (D1, D6 and D9) so I needed to route the 'booster' to the spare CB for D6 and D9 but I got a 'short' again.
D6 is the St. Paul yard and this was causing the short so now I had to diagnose the St. Paul yard.
I put the wires back to the original CB for D1.
Since I route 2 wires (the bottom 2 on the left side of the CB) from D1 to D6, the D6 short was causing D1 to 'blink red' for a 'short'.
This is the main 'terminal strip' for the St. Paul yard.
I started disconnecting 'output' wires until the 'short' stopped.
This area of the St. Paul yard, now, had to be diagnosed.
I found no problems so disconnect wires leading from this area to the roundhouse.
I checked the 'lead tracks' going to the round house and all was 'good'.
I then turned off the toggles leading to the turntable and round house tracks and the round house tracks were causing the short.
After 3 hours I found out that one of the tender trucks was off the track and causing the short 
After all the 'analysis' it made sense since 'logic dictated' that if I turn off the toggle to the 'affected' area, the short should have 'reset'. I just didn't turn off enough toggles.
Also, I failed to realize that removing the 'power' to D1 also removed power to D6.
I leave a couple tracks 'ON' for visual effects with all the LED's on the engine which was my 'down fall'!
