Double crossover question: Why wouldn't you always throw all four switches?

Maybe it's a power problem to power all four machines at the same time?

I'm also installing a double-crossover on my layout, and pondered the same question.  I came to this conclusion: if you're going to be using it only on the mainline, running trains through it, I don't see why not.  But, if it's in a location where you'll be doing some switching around it, it's possible to have a car fouling a switch while you need to throw another one.  In that case, I think you can tie the switches together two-by-two: which two depends on what you need to be able to do.  I hope this isn't too unclear!

The way real railroads did it was to have the two crossovers independent of each other. Think about it.  If you throw all four at once, and set it up so that when one is thrown straight the other is thrown for the crossover move, what happens if you want to have two straight through movements at the same time?  If you have all four throwing at the same time, if all four are straight, then all four will be for crossover moves.  That won't work. 

 

EdKing

Ed:

Some how that all makes sense.  I would prefer each pair operating independently of the other pair.  After all only one train is going to be using the crossover at a time.

 

Bud

I have one double crossover switch on my layout and operate each of the two switches with one switch motor.  The two switch motors are, in turn, both operated by the same switch control.  There are really only two positions of a double crossover  that can be operated at the same time: either straight through or crossing over to the other track; so with that you can control the whole crossover with that one controller.  In my case I'm using slow speed, low voltage motors that have sufficient torque to move both of the points on each end of the crossover.  They are mounted under the table and and the linkage is connected to both switches. 

 

Kind of neat to watch because with the slow motion and the slack in the linkage, none of the points actually move at the exact same time.

 

Paul Fischer

If all four switches are set to crossover, obviously only one train is using one pair of switches, the other two switches will not be involved and not foul anything.  It gives me one less thing to think about using just one switch control 2502.  I'm planning to get the long, #8 double crossover.

Operating one, two, or four switch machines at once is up to you but consider the practical side. Except for some of the slower operating switch machines they can generally draw one half amp or more when activated. That is one amp for two and two amps for four. Make sure your wiring can support that current draw for the activation time and that the switch control can withstand the strain. I do not believe the little DZ switch control can take a switching current of two amps for very long.

 

Al

Good point, thanks!  I was looking for a reason and you provided one!

No, that isn't possible. If you have even ONE of the crossovers set to diverging, the entire crossover is occupied. No other movements can take place through it and no cars could be sitting on one of the unused switches without fouling the operating track.

 

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Originally Posted by Edward King:

Huh? While you can have one side thrown straight while the other is thrown for the crossover move, you can't DO anything with the straight route. If a train is crossing over (either way) then the entire crossover is occupied. That is not how you would do this. You set it up so that ALL FOUR Switches are set to either Straight or Diverging. You would never want to set it so that one is lined straight and the other is lined diverging. That makes no sense.

 

If you want to run two straight-through moves, then ALL FOUR SWITCHES are set to the straight route. If you want to make a crossover move (either way) then ALL FOUR SWITCHES can be set to the Diverging Route.

 

The correct (and simplest) way to operate a double crossover is to set ALL FOUR SWITCHES to operate at once with a single pair of buttons or a single lever. There is absolutely no reason NOT to do it this way!

Finally someone who agrees with my practice! He must have been a Brakeman/Switchman.

Thanks guys!

Interesting to know! Learn something every day.

 

What about the hearsay I have heard on the vine about the AFT taking a crossover in emergency?

If you wire the crossover so ALL FOUR SWITCHES throw at the same time, you will NEVER have scenario where a locomotive attempts to go through a switch the "wrong" way. If all four throw at the same time, there is never a "wrong" way to go!

 

There are not THREE routes in a double crossover. There are only TWO. They are Straight Through and  Diverging. There is no third route...if you do it right.

 

You don't need "non-derailing" wired to work in a crossover (single or double) if you wire the machines to throw together because all the moves into the crossover are FACING POINT moves. The only time non-derailing comes into the picture is on a TRAILING POINT move where the switch is not lined for the direction of the movement.

 

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DEFINITION:

If you approach the switch on a track and have a choice of routes to go through the switch, that is a FACING POINT move. I could also use the analogy "Single to Double Track" is a FACING POINT move.

 

If you approach the switch from the "back" side and have only one choice of route through the switch, that is a TRAILING POINT move. I could also use the analogy "Double to Single Track" is a TRAILING POINT move.

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If you are throwing all the switches in a crossover at the same time, you NEVER have a trailing point move with the switch aligned against the movement, thus no need for the "non-derailing" feature.

The problem is, the diamond rails need to be powered to get engines through my Ross double crossover.  The diamond rails serve as a power feed -like a middle rail- when the switch is thrown to curve.  The opposite diamond rails can't be powered at the same time-they are the outside rails.  If all 4 diamond rails are powered and an engine crosses them- big, big short.  That is why you need the relays to switch power depending on the switch throw.  Without the relays and power to the diamond rails, engines will stall going across the diamonds.  Again, I hope John doesn't need the relays, but from my experience, he will.      

I have had problems with the 1008 relays too.  If I can't make them behave consistently I'll just manually switch the power with a simple SPDT switch.

Maybe I'm just "old fashioned". I created the same style crossovers with Lionel 45 degree crossovers and four 222 switches, one throw switch.

Am I missing something in the translation? Or is something simple being made hard to do.

Pappy, I plan to use the very long Ross #8 crossover which can have several dead spots causing shorter engines to stall.  That's why I need a way to switch power.

Yes, something simple was made hard to do.  If I had to do it over, I would go with 2 crossovers spaced apart.  Without elaborating too much, that would have given me more flexibility on my layout, and less aggravation.  It depends on your situation, of course.

I would do that too if I had the room.  My layout is almost nothing but broad curves.  I designed my longest straight section to accommodate the Ross #8 crossover since I have a dual track main. I have the broad curves because I have several long, scale engines and I want them to look their best.

okay if you use the tortise swith machines all you need is a relay to switch the power from one side of the diamond to the other.

 

as the tortise has a set of contacts that will activate the relay when those 2 switch machines are activated.

for those electrically minded its a snap for those like myself its a trial and error until it works.

that being said once I had it working I was proud of myself for not giving in hope you give it a try it really is worth the effort when you see your freight or passenger train roll from outer to inner loop especially if you have command control and have an engine idling with the smoke lofting up awaiting it's turn to move on down the track. $oo

Gentlemen, Thank you for the enlightenment. Wow, it's alot of hard work. I hope that everything works out great.

Whenever someone says "Gentlemen" my brain says "Who walked in?"  I guess it's from watching "The Three Stooges" too much.

Wire all 4 to switch at once and don't look back. You will be fine.  That's the way I did it when I have a dblcrossover. I changed to 2 separate crossovers because I wanted to wire for non- derailing.

 

Doug

tOne point that came to mind since my last post:  The Ross double crossover that I have on my layout is an older switch from before Ross worked out all of the "bugs'.  In the center of the actual crossing there was a plastic "blank" section wihout third rail power.  Steve has since added a power rail to this center section, but I had to cut a diamond  shaped piece of brass, which I screwed into place and wired into the center rail circuit.  The problem was with some of the engines with only two rollers, loosing contact and sudden stopping.  Easy fix.

Paul Fischer

 

Why would you need to do that? Did you not read what Rich said?

"If you are throwing all the switches in a crossover at the same time, you NEVER have a trailing point move with the switch aligned against the movement, thus no need for the "non-derailing" feature."

 

This of course ***-U-ME s that the operator will realign the crossover after the movement has been made; otherwise the train will be routed back to the same track it originated on, which may now be occupied.

 

QUESTION:

If the diamond has the new metal plate installed; does this elimenate the stall and need for the relays?

Not to change the subject (to me it is obvious that all four should be actuated simultaneously), but regarding what Paul wrote:

 

“…older switch from before Ross worked out all of the ‘bugs'.”

 

When did Ross work out all the bugs?! Of the 12 RCS I have on my layout, which I bought less than two years ago, I have derailing and dead spot issues with at least four of them. No problems with the 45 Atlas-O turnouts, though.

 

Alex

Even if that happens, you STILL do not have a Trailing Point movement where non-derailing would be required. The switches are all still properly aligned for movement through the crossover.

I should mention my Ross double crossover is about 10 years old.  Perhaps they have made improvements since then. Powering the middle diamond may alleviate the need for the relays.  Maybe try it all 4 together, if engines stall , go to plan B.

About 2 weeks ago I came downstairs first thing in the morning,  without putting my contacts in my eyes, (I'm horribly blind without them), powered up the layout and ran an engine over the trailing switch turned the wrong way.  ZAP!- there went $12 and an hour of my time to replace the relay.  I've got 1 more in reserve.  I'm hoping it stays in the closet for a long time.  Good luck.

I should have added that I did not want both track changes at the same location and once I changed tracks I did not want to have to remember then throw the switches again.  I understand that I would not need to worry about derailing, just the train going back to the original track.

 

Doug

Doug, I'm sorry, but I have no idea what you are trying to say.

Alex and William:  what I was referring to was the "dead spot" in the center of the crossing.  I realize that some switch motors have contact points and instructions for powering the short running rails in the crossing with the continuity of the crossing track.  (Not sure if I'm making myself clear on this)  On a double crossover you can't do that because the switch positions are the same regardless of which route through the crossing is taken.  So you leave those short rails unpowered: neither connected to the outside rails nor to the power rail.  Instead, make a flat contact strip for the center of the crossing that is connected to the power rails.  This will provide enough contact for the rollers on your engines that will keep them from stalling.

 

Hope this helps.

 

Paul Fischer

i would not throw all 4 switches at the same  time-seems like alot of extra wear that doesnt need to happen. at some time,movable  parts on a switch wear out and fail .-jim

Gentlemen, if we ran our trans the way real train run, no power drawn from the track, those that want to throw all four switches would be correct. Extra wear an tear on the unused switch but OK. Since we draw power from the track there are often rails that need to have power switched to them for various reasons. Depending on your setup this can be simple or complicated. For this reason it is often desirable to switch only one cross-over direction at a time (two switches). In looking back through the post it seems that the argument is simular to is 2 plus 3 equal to 5 or is it 3 plus 2 equals 5. If you want to switch all four switches at the same time go ahead, the switch manufactures will love you and your wiring will be simpler. If your equipment will not make it through all those insulated points without some help that requires you to switch power then switch only two switches and deal with the complex wiring. The correct way is which ever works for you!

 

By the way, if you are having problems with shorts destroying 1008 relay contacts then for peet sakes get yourself some relays with contacts that will withstand the short circuit current and use them. Use the 1008 to turn the larger relay on and off.

Rich, sorry, I wasn't very clear.  I should never post when I'm in a big hurry.  What I was trying to say is that I eliminated the dbl crossover because I wanted to relocate the outside to inside crossover (going north) to a location closer to my yard, but I did not want to move the inside to outside (going north) crossover.  I understand that with the dbl crossover with all switches thrown the trains would just keep changing tracks and there would be no need for non-derailing. 

 

Wiring the dbl cross with the 2 opposite switches together would cause a derailment if the train crossed (outside to inside) and then came back around to the dbl and the switches were not thrown back.  I have been known to forget to throw the switches back.

 

Doug

OK, Doug. I understand now.

 

However, if your "Switch Tender" forgets to line the switches on the main track after trains have cleared them, maybe you should look for a new man to handle the job. 

 

Oh...wait...that's YOU! Never mind. 

Let me get this straight, Rich.

 

If you have all four switches throw at once, they are either all four lined straight through or all four lined for crossover movement.  Right?

 

Now, if all four are lined for crossover movements, the only move you can make is to have a movement crossover through the first set and then cross right back over through the second.  I fail to see how this would be an advantage.

 

Now if you wire them so that one crossover is straight and the other for crossover movement, and they all four throw at once, you can't ever make a straight through move on either track.

 

Maybe you better 'splain it to me.  I ran several CTC interlocking towers and then dispatched trains on a CTC district that had several double crossovers, and to have had them all work together at once would have been silly.

 

But I'd be happy to have someone straighten me out (pun intended).

 

EdKing

As far as I know, a double crossover has the crossovers parallel to eachother, not in series as described above. The diverging lines make an "X"

For what it is worth, our Kato "N" gauge unitrack double crossover is set up for all four points to throw together.

 

Here is a photo I found on the web: