Reverse loops

Surovi
Posts: 64
Joined: Fri Nov 03, 2017 9:21 am

Re: Reverse loops

Post by Surovi »

Hmmm...I`m not sure that we understand each other :)

Can I use point without motor and just leave it unattended?
I don`t know how the train behaves when it comes back to a switch in/from the return loop and how it affects the switch :silent: :oops:
I`m a noob :oops: sorry

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CFRiad
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Location: Vancouver, Canada

Re: Reverse loops

Post by CFRiad »

Surovi wrote:Can I use point without motor and just leave it unattended?
There are pretty much three options:
1. Control the switch manually -- you eliminated this option since you want to leave it unattended
2. Motorize the switch and have the train control it -- this is completely automated as dileTTante described in earlier in this thread. Wiring is a bit tricky but, If done right, it works very well.
3. Have a spring-loaded switch -- this is mechanical automation: the switch is always held in one position by the spring, directing the train into the loop. When exiting, the train approaches the switch trailing the points and the wheel flanges force the points away from from stock rail allowing the train to pass the switch. This is prototypical, btw, some railways use these at unattended passing loops.

Option 3 can be tricky to set up and maintain: the spring has to be strong enough to hold the points tight, lest the train derails when enters the loop facing the points, but not too strong, allowing the flanges to cut the points open when approaching from the trailing end. If the spring is too strong the wheels of lighter cars will jump over the points rather than splitting them.

If you need more details about any of these options let me know.

Surovi
Posts: 64
Joined: Fri Nov 03, 2017 9:21 am

Re: Reverse loops

Post by Surovi »

Thanks both!

All is clear.
I`ll consider options.

Surovi
Posts: 64
Joined: Fri Nov 03, 2017 9:21 am

Re: Reverse loops

Post by Surovi »

Well...another one :)
Does polarity changes on the main track between two loops?
I would like to connect one circle with loop to loop railroad.

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krokodil
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Joined: Tue Jan 29, 2013 6:46 pm

Re: Reverse loops

Post by krokodil »

Turnout
Turnout
The 3rd option will not work well on model railroad. Not just the spring adjustment will be critical but also the electrical management.
On the picture above you can see the situation. It can work only in case when both closure rails and the corresponding points are always on the same polarity as the nearest stock rail, and insulated from the frog. The frog in most cases remains insulated from the tracks ( no polarisation). You will not have any mechanizm for polarisation.
On top of that - different from the real railroad, the weigth of the wheels is very low, and such spring loaded switches may work better under locomotives, but will fail under the cars. ( also depends on the wheel flanges).
In case of loops you always have some electrical unit to swtch the polarity of the tracks, what can be used on a simple way to activate the switch motor as well, ie each polarity has its settings also for the points. This gives you the best operation. ( Option 2)
Greetings from Austria
E.T.

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krokodil
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Re: Reverse loops

Post by krokodil »

Surovi wrote:Well...another one :)
Does polarity changes on the main track between two loops?
I would like to connect one circle with loop to loop railroad.

You have to change it. When your train goes into the loop it is one polarity, when the train leaves the loop - goes back to the main track, is the another polarity.
In the simplest design the loop is oneway, ie the trains are running in the loop always in the same direction (there is no need for polarity change), and the outer (common) main tracks change the polarity.
Greetings from Austria
E.T.

Surovi
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Joined: Fri Nov 03, 2017 9:21 am

Re: Reverse loops

Post by Surovi »

Thanks!
I thought so.

Is there a way to engage the train from the other track (closed circuit) to Loop to loop track?

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krokodil
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Re: Reverse loops

Post by krokodil »

When I correctly understood you, you want to combine the loop to loop portion of your layout with the rest.
If the connection to the rest of the layout is somewhere within the loops there is nothing much to do, just to install an extra switch and the trains can leave or enter the loop section.
If the connection is on the main track (between the two loops, you have to insulate the entire loop from the rest of the layout (both rails). The connection track between the loop portion (main track) an the rest of the layout should maintain the polarity issue. For example can be thrown only in case when the train runs on the loop section in correct direction and on the main layout is the correct polarity. This option can be quite complex......:-)
Greetings from Austria
E.T.

Surovi
Posts: 64
Joined: Fri Nov 03, 2017 9:21 am

Re: Reverse loops

Post by Surovi »

Thanks!

It`s complicated....yes....hmmm

Surovi
Posts: 64
Joined: Fri Nov 03, 2017 9:21 am

Re: Reverse loops

Post by Surovi »

Does this apply to digital too?
Some people say DCC does not have these problems.

This is the track plan:
Image

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