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Main through diverging route

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Main through diverging route
Posted by corsiar on Sunday, September 08, 2019 2:24 PM

Have to move the track coming from the black thuder mine to the main to this spot to get enough track to support a 16 car train. A PECO large radius turnout has aprox the same 36" radius as the main in this spot. It works out good but the main is now running through the diverging route of the turnout. Is this a bad idea or not?

 

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Posted by Overmod on Sunday, September 08, 2019 3:02 PM

In practice it would involve more wear on the points and a couple of other parts of the structure, implying more regular maintenance to avoid failure.  You may have to keep the equivalent of diverging-clear as your fastest speed due to the effective lack of spiraling in the transition, and I think that would apply 'both ways'.   

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Posted by RR_Mel on Sunday, September 08, 2019 3:05 PM

I have two of the same turnouts on my layout both the same as you need to do.  I’ve never had a problem with either even at higher speeds.
 
 
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Posted by jeffhergert on Sunday, September 08, 2019 3:25 PM

Overmod

In practice it would involve more wear on the points and a couple of other parts of the structure, implying more regular maintenance to avoid failure.  You may have to keep the equivalent of diverging-clear as your fastest speed due to the effective lack of spiraling in the transition, and I think that would apply 'both ways'.   

 

If we're thinking in prototype terms, how fast is Diverging Clear?

Jeff

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Posted by richhotrain on Sunday, September 08, 2019 4:39 PM

I think that it is a bad idea. I have always designed my layouts such that the mainlines always use the straight through route when entering a turnout to avoid any possibility of derailments. In my experience, trains always need to slow down when entering the divergent route on a turnout to eliminate any possibility of derailments.

Rich

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Posted by York1 on Sunday, September 08, 2019 4:50 PM

corsiar
Have to move the track coming from the black thuder mine to the main to this spot to get enough track to support a 16 car train. A PECO large radius turnout has aprox the same 36" radius as the main in this spot. It works out good but the main is now running through the diverging route of the turnout. Is this a bad idea or not?

 

I faced the same problem.  Rather than tear out and move large sections of track, I ran the mainline through a diverging route.

If I was starting over, I wouldn't do it, but I have never had a problem with trains running through it.

Saints Fan John

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Posted by corsiar on Sunday, September 08, 2019 5:22 PM

What about curved turnouts?

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Posted by floridaflyer on Sunday, September 08, 2019 5:48 PM

Space constraints forced me to put an Atlas #6 divergent route as the main. Installed it 13 years ago, run at normal speeds and have not had one problem. Best practice is not to do it if possible, but in a pinch it should not be a problem  

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Posted by RR_Mel on Sunday, September 08, 2019 5:53 PM

The two turnouts in my post above are Peco curved turnouts both with the 30” diversion in a 30” curve and absolutely no derails or problem since I installed them about 6 years ago.  I can run either DC or DCC trains at full throttle through the curved diversion (mainline) or the non diversion track.
 
It might not be prototypical but they both work perfect.  I originally used Atlas #6 turnouts with the straight track feeding the siding and the diversion was the mainline, never a problem.  I swapped the Atlas with the Pecos further into the curve to gain the length of the siding.  By swapping out the turnouts I gained 3’ of siding without any problems allowing for longer trains on the siding.
 
 
The siding is the upper track, the layout is 14’ wide.  Moving the turnouts further into the curve didn’t change any operations other than give me more track in the siding.  I have never had a derail on either the main or the diversion.  To make it even better both turnouts and tracks are hidden.
 
It can be done and work trouble free, six years of hard running without any problems!!!!
 
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Posted by ROBERT PETRICK on Sunday, September 08, 2019 6:21 PM

The Wind River Canyon peninsula on my N-scale layout is essentially one giant balloon track; so however you shake it, trains always either enter a diverging route or emerge from a diverging route. The nozzle of the balloon is a straight Peco large radius turnout, about a No 8 equivalent.

Reasonable speeds cause no problems, and neither do unreasonable speeds.

Robert 

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Posted by jjdamnit on Sunday, September 08, 2019 7:47 PM

Hello All,

With permission, and forgiveness, I'm going to get a bit semantical...

"The main line, or mainline in American English, of a railway is a track that is used for through trains or is the principal artery of the system from which branch lines, yards, sidings and spurs are connected. It generally refers to a route between towns, as opposed to a route providing suburban or metro services." Wikipedia

Yes, I just quoted Wikipedia.

I have seen mainlines making a pathway through yards that weren't necessarily a straight run of track.

The "diverging" straight sections might be considered yard leads in your plan.

Personally I see nothing wrong with a curved main to accommodate the surrounding topography, yards and industries.

On my pike I modified a PECO curved turnout to re-route the mainline, so switching duties could be performed without interfering with mainline traffic. 

Previously- -through bad track planning by management- -the trains on the main would have to negotiate an "S" section though a series of turnouts to avoid yard operations.

Good luck and as always...

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by Overmod on Sunday, September 08, 2019 7:49 PM

jeffhergert
If we're thinking in prototype terms, how fast is Diverging Clear?

Medium speed modified by characteristics of the particular 'diversion' or subsequent route.  The figure I usually see is 30mph base.  I suspect you know far more about the actual signal and speed rules that would apply to a situation such as this.

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Posted by jeffhergert on Sunday, September 08, 2019 8:04 PM

Overmod

 

 
jeffhergert
If we're thinking in prototype terms, how fast is Diverging Clear?

 

Medium speed modified by characteristics of the particular 'diversion' or subsequent route.  The figure I usually see is 30mph base.  I suspect you know far more about the actual signal and speed rules that would apply to a situation such as this.

 

Our Diverging Clear is Proceed on the diverging route not exceeding the speed of the turnout.  We have 15, 30, 40, 50 and 60 mph turnouts that are traversed on a Diverging Clear signal.  The speed through the turnout is prescribed by the turnout, not the signal.

Jeff 

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Posted by Doughless on Sunday, September 08, 2019 8:57 PM

For the prototype, how does a typical Class 1 system map get to look the way it does unless many main lines run through diverging routes?

For our models, I assume if the embedded radius is broad enough and the turnout is installed well, I don't see a real problem.

Having said that, I think it looks kind of funny and I would always try to avoid it for that reason. 

 

 

- Douglas

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Posted by SPSOT fan on Sunday, September 08, 2019 10:51 PM

I personally avoid having mains take diverging routes when I track plan, because I’ve heard from a few railroaders that the prototype rarely does that. This is because diverging turnouts increase the risk of derailments and require a speed resriction (I think 25 or 30 mph) to operate safely.

Now this weight is not a major issue in HO scale as the rolling stock is not as heavy. Even in 7 1/2 inch scale livesteam, one of the biggest, and heaviest scales, people routinely go through diverging routes at top speed without issue.

So to the OP I’d say it is okay to route the main through a diverging turnout. You could easily run through it at track speed without issue. Still if you want some operational interest you could have crews go through the turnout at restricted speed.

Regards, Isaac

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Posted by corsiar on Sunday, September 08, 2019 11:26 PM

It is a small 9' x 10'  N scale layout that I will be operating by myself. 

Laying cork now then will lay the main line track and test. If it doesnt work I can pull it up and try something else.

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Posted by hon30critter on Sunday, September 08, 2019 11:47 PM

Hi corsiar,

Do what you have to do! It's a model railroad, not the real thing. If you need to use the diverging route as the mainline there is nothing wrong with doing that. That is, of course, provided that you lay your track properly and that you run at reasonable speeds.

Curved turnouts work great for coming off the mainline in the middle of a curve. Our HO club layout has several situations where we have used Peco Code 83 curved turnouts to great advantage where the inside curve is the mainline.

I envy those modellers who can claim that all of their through routes are on the straight side of the turnouts, but that takes space. If you don't have the space, why get your shorts in a knot because you are violating some prototypical rule. Who cares? I'll say it again, do what you have to do.

Cheers!!

Dave

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Posted by gmpullman on Monday, September 09, 2019 12:16 AM

For example:

 MARCP877, West, Point of Rocks, MD by Chris G, on Flickr

Good Luck, Ed

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Posted by richhotrain on Monday, September 09, 2019 4:48 AM

I would suggest that just because it happened sometimes on the prototype is really not sufficient justification to do it on a model railroad. Running trains through the divergent side of turnouts can be a delicate process requiring slower speeds to avoid derailments. I would leave the divergent side of turnouts to entries to yards and sidings and spurs.

Rich

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Posted by Doughless on Monday, September 09, 2019 8:03 AM

gmpullman

For example:

 MARCP877, West, Point of Rocks, MD by Chris G, on Flickr

Good Luck, Ed

 

I've tried to post a pic of the BNSF, UP, CSX, or NS system maps, but failed.  They look like spider webs superimposed on top of an arterial MRI.  

I would think the above pic would happen a few dozen times on each system, at least.

Maybe what we're talking about is the tangent track leading into an industrial spur instead of another mainline?

That may be a different animal.

- Douglas

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Posted by Mark R. on Monday, September 09, 2019 9:17 AM

gmpullman

For example:

 MARCP877, West, Point of Rocks, MD by Chris G, on Flickr

Good Luck, Ed

 

Very proto-typical .... provided the diverging route is through a no. 24 switch ! Smile, Wink & Grin

Mark.

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Posted by Overmod on Monday, September 09, 2019 9:31 AM

jeffhergert
The speed through the turnout is prescribed by the turnout, not the signal.

That is what I meant to say, but didn't say 'well enough'.  The characteristics of the turnout and subsequent route would determine both the speed and the expected 'next' signal indication, with some default speed logically being provided where it might be unknown.  So exactly as Jeff indicates.

On a model railroad, of course, the largest radius you have is probably more sharply curved than Jeff's 15mph turnout, and while prototypical radius doesn't need to be strictly observed there are likely some operational quirks... on the other hand, it's unlikely you'd be coupling or shoving on the main as opposed to 'back into the yard' so there may actually be an operating advantage of sorts having the diversion being a tangent up to the ladder.

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Posted by MisterBeasley on Monday, September 09, 2019 9:44 AM

I have a few of them.  On the old Code 100 part of my layout, I use Peco turnouts, some double-curved and on the newer Code 83 part the only one is a WS double curve.

I have no problems with any of these but I am meticulous about reliable trackwork and will spend hours fixing them until I have zero problems.

I do think that Tortoise or Peco machines to drive these hold the points in place better than Atlas machines.  That is why I chose Pecos for these situations.

It takes an iron man to play with a toy iron horse. 

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Posted by BroadwayLion on Monday, September 09, 2019 10:17 AM

jeffhergert
If we're thinking in prototype terms, how fast is Diverging Clear?

 

That depends on the turnout. The speed on diverging routes is controlled by the frog and not by the signal aspect.

 

An number 8 frog would be limited to 16 mph. A number 10 frog would be limited to 20 mph. A number 20 frog would be limited to 40 mpg, but anything faster than that would need to have moving frog points as well as moving switch points.

 

 

Your standard #4 turn out would be limited to 8 mph, and a #6 to 12 mph.

 

Those sort of mach subway speeds, mane lion or knot.

 

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Posted by selector on Monday, September 09, 2019 10:29 AM

Remember Saluda Grade?  It had a top descent speed of 8 mph, and at the bottom, the 'main' route diverged away from the runaway route.  If the person 'manning' the switch didn't hear three whistles from the oncoming descending locomotive, he didn't throw the switch and the train was deemed to be in distress.  Due to the high speeds expected, the idea was that the through route was the safest, leading up a steep control ramp.

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Posted by corsiar on Monday, September 09, 2019 2:42 PM
Going to ask the stupid question. This is pointed towards mrr turnouts. Does it matter which way a train runs through a turnout? On my PECO code 55 large radius turnouts a car seems to run the same either going straight or through the diverging route. The wheels drop into the gap going either way. The wheels are not even close to the wing rails going either way. The wheels do hit the point of the frog pretty hard but seems the same either direction.
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Posted by ATLANTIC CENTRAL on Monday, September 09, 2019 4:57 PM

A few practical thoughts:

The prototype does what it must, and uses much larger curves and much larger frog numbers than our models, including moving point frogs when needed.

None of that applies to our models.

The substitution radius of a #6 or #8 turnout easily exceeds the typical radius curves most of us are using, generally allowing the turnout to act as an easement.

So why would it be a problem to run the main thru the diverging route? Just like the photos above of the Point of Rocks junction?

Every layout I have ever built has had a few such locations, never with any issues. Same has been true of a number of layouts I have designed and/or worked on for others.

My new layout will have a number of such track arrangements, mostly with #8 turnouts and curves above 36" radius.

I would forge ahead.

Sheldon

 

    

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