# Placement of blocks



## surveyorbill (Jul 14, 2013)

Hello. The attached diagram shows an inner loop with 2 deadend services and outer loop with a turnout. A connecting switch set up between loops is also shown. Proposed blocks are shown. 
Does the plan give anybody heartburn? Like they say 'Measure twice and cut once'. Refer to pictures in my trestle post if it helps. Thanks to those who have gone before. BR


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## Southern (Nov 17, 2008)

What you have looks good. I would also cut the loops in to at least two blocks each. That will make it easier to move two trains between the loops.


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## DonR (Oct 18, 2012)

BR

Looks like a good opportunity for your trestle work on that layout.

If you are running DCC, you might want to add in a 2 or 3 more
passing sidings so you can run trains in opposite directions on your
single track mains. That makes for fun operations.

Don


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## Walman (Dec 18, 2011)

surveyorbill said:


> Hello. The attached diagram shows an inner loop with 2 deadend services and outer loop with a turnout. A connecting switch set up between loops is also shown. Proposed blocks are shown.
> Does the plan give anybody heartburn? Like they say 'Measure twice and cut once'. Refer to pictures in my trestle post if it helps. Thanks to those who have gone before. BR


Sorry this is probably a basic question I should know the answer to but why do you need to block the siding tracks on the inner loop? Is that just so you can keep the power off when not in use? 

Are you running DCC? Just curious.

Walman


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## alcoman (Nov 4, 2009)

Walman, some things that the extra blocks could help with, even with DCC, are fault isolation and simply having a place to park locomotives you don't want to pick up or keep powered.


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## surveyorbill (Jul 14, 2013)

*Sidings on Inner loop.*



Walman said:


> Sorry this is probably a basic question I should know the answer to but why do you need to block the siding tracks on the inner loop? Is that just so you can keep the power off when not in use?
> 
> Are you running DCC? Just curious.
> 
> Walman


 Hi. I am too old to change to this overly advertised DCC trickery fad which I predict will soon fade out.
I thought I needed a block on the 3 deadend sidings on inner loop to isolate 3 different enterprises or factories. Cant run them all at the same time. Or can I? Dont worry, I am still trying to sort out the wires. BR


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## Walman (Dec 18, 2011)

alcoman said:


> Walman, some things that the extra blocks could help with, even with DCC, are fault isolation and simply having a place to park locomotives you don't want to pick up or keep powered.


OK that makes sense. The whole subject of isolation gaps and blocks, even with DCC, keeps me up at night. In my planning I can usually tell where I think I am going to need them but I am always concerned I will miss a spot. I'm still a couple weeks away from installing the electrical so the lost sleep is adding up 

Walman


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## surveyorbill (Jul 14, 2013)

Walman said:


> OK that makes sense. The whole subject of isolation gaps and blocks, even with DCC, keeps me up at night. In my planning I can usually tell where I think I am going to need them but I am always concerned I will miss a spot. I'm still a couple weeks away from installing the electrical so the lost sleep is adding up
> 
> Walman


That is where I am. I have been looking at wiring and gaps for a year. I did some on previous layout so have some little experience. I have EZ track to hook up to which eliminates a need to solder and Atlas #215 switchs for a 2 cab/controller set up. I got a copy of Atlas booklet #12 wiring book. My case is on page 26. I am fine with not getting in a hurry. I find that the common inner rail handles all my 'Trestle' 2 loop layout just fine. 

Picking where to gap outer rail is the thoughtful problem. I find that a Dremel tool with a #426 abrasive wheel is my answer to cutting a gap in my as-built outer rail. This cutting wheel is 0.04 thick and is an adequate gap dimention. I practised on scrap rail to get a feel for the process. I tried a metal hand saw and plastic rail insulators which failed for me. 

A final note is to hook a wire and alligator clamp to your first switch position to test a blocked rail to get the correct wire to make hot. EZ connectors have 2 wires, one for hot and one to ground which is not needed as you have the inner rail to common. Right? Keep the faith. BR


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## DonR (Oct 18, 2012)

Where you indicate an insulator gap in the 'outer' rails seems the right place for what you 
want to do in DC. You would use the same gap and common rail system for both the inner loop and the outer loop. 

Where you have the two crossovers connecting the outer to the
inner loop you'll want to have gaps in BOTH rails.

Unless you plan to light or power animation in your industries
the only reason to shut off power in a spur is to have place to park a loco
not in use. 

Looks like a good layout.

Don


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## surveyorbill (Jul 14, 2013)

*Sever bothrails???*



DonR said:


> Where you indicate an insulator gap in the 'outer' rails seems the right place for what you
> want to do in DC. You would use the same gap and common rail system for both the inner loop and the outer loop.
> 
> Where you have the two crossovers connecting the outer to the
> ...


Please explain "Where you have the two crossovers connecting the outer to the
inner loop you'll want to have gaps in BOTH rails." Do you mean 1 outer rail per crossover or or outer and inner rails or 2 rails per crossover (4 rails)? If outer and inner are gapped, will this not sever my common rail theory? I am gapping power and not ground am I not?:dunno: PS Page 30 of the Atlas Wiring book shows this diagram and does NOT gap the common rail.


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## DonR (Oct 18, 2012)

What I mean is that you would sever BOTH rails where there is
a connection between the outer loop and the inner loop through
your turnouts. Yes, both turnouts will need it.

That would not affect your common rail theory in each loop. But
it would avoid a short circuit when your train moves from, say,
the outer to the inner loop. For that you would set both loops
to, say, forward and the loco would move smoothly through
the turnouts. It would need no additional wiring though.

Because you will be using the ability to run trains forward and
backward in either DC loop you will have times when the polarity
of one loop is opposite that of the other. That would be a short
circuit without the gaps.

Don


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## surveyorbill (Jul 14, 2013)

*ground*

Hi I can follow that. It will mean to have the ground seperately provided to both outer and inner circuit ?? As I have it now the EZ connection has 1 ground connected to the entire 2 loops layout. 

They didnt teach this in torpedo school.


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## DonR (Oct 18, 2012)

Yep Bill

That's the way I did it on an old N scale DC layout.

Run a ground from the power pack for the outer loop to it's loop.
And a ground from the power pack for the inner loop to it's loop.

When you decide to run a train from one loop to the other you simply
make sure the destination loop is set for same train direction as the
loop it is coming from else the train will see saw back and forth or
trip a circuit breaker.

It would seem that a torpedo would be a pretty complicated thing with
a lot of electrical circuits. You must know a lot about them.

Don


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## surveyorbill (Jul 14, 2013)

DonR said:


> Yep Bill
> 
> That's the way I did it on an old N scale DC layout.
> 
> ...


There was a little ditty we learned to remember resistor color codes but it has escaped into neverland at this late date. I am on last row left and 18 years dumb. The green thing in the tube is a Mk 37 ASW torpedo on USS Renshaw DD499 in 1967. Fair winds and following seas to all our buddys here. BR


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## DonR (Oct 18, 2012)

Quite a crew you had there. I get the feeling that torpedo room may have
been a pretty warm place to work.

Radio Shack resistors come with the color code printed on every
package so you don't have to use the noggin for them any longer.

Don


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