DCC two reversing loops with crossover - will this track plan work?

[AchimK]

Hello

 

I'm working on the track plan for the fiddle yard of a small (8 by 4 foot essentially) roundy roundy layout on a piece of ply.

The diagram shows my idea as to how to include two reversing loops including a crossover (not a double slip).

I'd like two reversing loops so that I don't have to reverse the trains through one when changing direction.

Entry to the lot is from the left or right. This is the lowest level.

 

Will this work at all on a DCC layout (with reversers correctly wired in) or can I rubbish it now and start afresh?

Planning to use PECO track.

 

Many thanks trendsetters.

Achim

[Pete the Elaner]

I don't see why it wouldn't work, but you would need to make the reversible (yellow) section as large as possible, so an entire train will fit in it.

You can only have 1 train at a time in the reversible section. This may make you feel that the double loop is an unnecessary complication.

[RobinofLoxley]

You are best off avoiding track combinations like this. Regardless of whether it works on paper, there are risks of shorts across the crossover tracks even if its isolated ('Insulfrog' type), . I also think there could be problems with the polarity change-over if you happened to have stock entering or exiting the two reversing sections at the same time.

Best if you post this in 'Layouts and track planning'

Edited March 10, 2021 by RobinofLoxley
Deleted some rubbish

[John ks]

If the 2 reverse loops are connected as shown then the only problems I see is the crossing  which would have to be an insulfrog 

 

 

 

9 hours ago, RobinofLoxley said:

there are risks of shorts across the crossover tracks even if its isolated ('Insulfrog' type)

Depending on which way the 2 ARU's (auto reversing units) are, the phasing(DCC for polarity) of the rails can be as shown

In the top example a wheel can bridge between the red & black rails, causing a short (blue circle)

in the lower example a wheel can bridge between the red & black rails, causing a short ( green circle)

the easy fix is to paint the top of the rails(where the short occurs) with fingernail polish ( I use clear)The polish will need  to be renewed as it wears away.

9 hours ago, Pete the Elaner said:

but you would need to make the reversible (yellow) section as large as possible, so an entire train will fit in it.

As Pete said above or the train has to be limited to the length of the part of the loop between the insulated joiners

John

 

 

[KingEdwardII]

If you want to use this track configuration, I think that the simpler way to handle the potential shorting issue on the diamond crossing is to have the power to the tracks in each of the reversing loops controlled by the entry & exit turnouts for each of the loops. The power should be off unless the turnouts are set for that loop - and in addition the turnouts should be interlocked so that they cannot be set for both reversing loops at the same time. 

 

This approach removes the shorting issue completely, and also ensures no conflicting movements can take place. This would also allow for use of an electrofrog diamond.

 

Yours, Mike.

[AchimK]

9 hours ago, John ks said:

If the 2 reverse loops are connected as shown then the only problems I see is the crossing  which would have to be an insulfrog 

 

 

 

Depending on which way the 2 ARU's (auto reversing units) are, the phasing(DCC for polarity) of the rails can be as shown

In the top example a wheel can bridge between the red & black rails, causing a short (blue circle)

in the lower example a wheel can bridge between the red & black rails, causing a short ( green circle)

the easy fix is to paint the top of the rails(where the short occurs) with fingernail polish ( I use clear)The polish will need  to be renewed as it wears away.

As Pete said above or the train has to be limited to the length of the part of the loop between the insulated joiners

John

 

 

 

Dear John, many thanks for this. Great and helpful advice, I appreciate you taking the time.

Achim

[AchimK]

2 hours ago, KingEdwardII said:

If you want to use this track configuration, I think that the simpler way to handle the potential shorting issue on the diamond crossing is to have the power to the tracks in each of the reversing loops controlled by the entry & exit turnouts for each of the loops. The power should be off unless the turnouts are set for that loop - and in addition the turnouts should be interlocked so that they cannot be set for both reversing loops at the same time. 

 

This approach removes the shorting issue completely, and also ensures no conflicting movements can take place. This would also allow for use of an electrofrog diamond.

 

Yours, Mike.

 

Dear Mike, thank you for taking the time to comment. Very helpful indeed!

Achim

[john new]

19 hours ago, AchimK said:

Hello

 

I'm working on the track plan for the fiddle yard of a small (8 by 4 foot essentially) roundy roundy layout on a piece of ply.

The diagram shows my idea as to how to include two reversing loops including a crossover (not a double slip).

I'd like two reversing loops so that I don't have to reverse the trains through one when changing direction.

Entry to the lot is from the left or right. This is the lowest level.

 

Will this work at all on a DCC layout (with reversers correctly wired in) or can I rubbish it now and start afresh?

Planning to use PECO track.

 

Many thanks trendsetters.

Achim

Ignoring the track wiring issue on a practical matter - do you have access all round and/or are you going to be cutting holes for ducking under to get inside each circle? At a four foot stretch you won't reach anything at the back if there is a problem. How do I know, I did have a four foot square board with a circle for running in locos sitting on a bunk bed in between visits by relatives. An absolute nightmare if I wobbled it and anything came off in the back corner.

 

I ask as it looks a bit like the yellow cut out area is perhaps your access zone.

 

Edited March 11, 2021 by john new
Added extra observation

[Hamburger]

Due to the crossing and the single connection track at the top it should not be possible to run more than one train through the loops at a time.

So both loops can be connected by the crossing without problems and just one module is needed.

Even a locomotive or a short train sitting inside of one of the loops waiting until the other train passes would not change anything.

[ITG]

42 minutes ago, Hamburger said:

Due to the crossing and the single connection track at the top it should not be possible to run more than one train through the loops at a time.

So both loops can be connected by the crossing without problems and just one module is needed.

Even a locomotive or a short train sitting inside of one of the loops waiting until the other train passes would not change anything.

I think I agree with this. In fact, isn’t it the top straight between /above the two loops which is fact the reversing section in practice? Without that, if my finger tracing is to be believed, the train cannot reverse. If that logic is correct, the challenge is the shortness of that section, as not being long enough to contain a complete train.

[AchimK]

22 hours ago, Hamburger said:

Due to the crossing and the single connection track at the top it should not be possible to run more than one train through the loops at a time.

So both loops can be connected by the crossing without problems and just one module is needed.

Even a locomotive or a short train sitting inside of one of the loops waiting until the other train passes would not change anything.

 

Morning Hamburger and Mike

 

Great advice and I came up with the following diagram. If power to both loops is controlled by the entry and exit turnouts (mutually exclusive) then I think I could wire the reverser as shown. Would you agree with this?

 

I'm assuming when switching the points, that means first switching power off to the whole reverse loops section and then setting the opposite points and powering on again. In my mind this can then both be handled by the same reverser unit.

 

Many thanks

Achim

Edited March 12, 2021 by AchimK