Double Crossover with a Double-curve Turnout

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beiland

Well-Known Member
#1
Double Crossover with a Double-curve Turnout


I'm proposing to build this particular double crossover arrangement between my 2 mainlines as they enter/exit the upper deck of my double deck layout. Three of the turnouts are Med radius Peco's (nominal diverging radius 30”). The 4th turnout is a double-radius Peco with nominal radii of 30/60”).


I was hoping to insert a very short radius track between the crossover itself and the larger radius of the curved Peco. As I have it mocked up here that short radius piece is 22” radius. Would that work?,...or maybe 24”r piece??


























It looks smooth enough to me. I'm just not sure how such a change in radius can effect things?
 

NYC_George

Well-Known Member
#2
I certainly like the looks of it. If it all works I think it will be a great addition. I got rid of all my 22r tracks. Short wheel based locos were fine but the long based loco and passenger cars no. I would go as high of radius as you can go.

George
 

Iron Horseman

Well-Known Member
#4
I'm proposing to build this particular double crossover arrangement between my 2 mainlines as they enter/exit the upper deck of my double deck layout. Three of the turnouts are Med radius Peco's (nominal diverging radius 30”). The 4th turnout is a double-radius Peco with nominal radii of 30/60”).

I was hoping to insert a very short radius track between the crossover itself and the larger radius of the curved Peco. As I have it mocked up here that short radius piece is 22” radius. Would that work?,...or maybe 24”r piece??

It looks smooth enough to me. I'm just not sure how such a change in radius can effect things?
I think it would be fine. As I recall you have 22" radius other places on the layout so it would not be a stand alone pinch point. The curved Peco would act as an easement.
 

beiland

Well-Known Member
#5
Yesterday I discovered a problem with some of my NEW Peco crossovers. Four of my new Pecos had problems,...2 had plastic joiners in a few of the tracks had 'dips' in them, and 2 of them had little tip projections into the flangeway.​

These were discovered when I experimenting with running a model 6 axle tender over them. Granted the flanges on these wheels were ever so larger than standards these days, but it was just enough to cause them to bump way up in the air as they encountered these blips in the flangeways. And I double rechecked the gauge on these wheel sets, and they were right on.




This is the tender that had the suspect wheels that encountered the problem thru those X crossings. It came with a nice IHC Mehano steam locomotive built in Slovenia.















I won't really describe these wheels as 'cookie cutters', but I guess their profile interacted badly with the defect in those Peco X crossings. They do not seem to have a problem with the std Peco turnouts, nor with any of the multiple Atlas turnouts I had on my old Central Midland layout.
 

beiland

Well-Known Member
#6
First stage of testing


Yesterday I got one of my DC power packs and several locomotives out to see what happens when I try to run trains thru the 'custom double crossover' I am proposing. I did a rather 'slap it together' job in the interest of brevity, and not wanting to cut up too much track until I arrived at a final solution (so please excuse the blue tape holding things in place temporarily.


















Regrettably I continued to utilize that same sort piece of 22” sectional track, just to see what would happen. Not only was it marginal in curvature, but it had sligthy deformed ends I discovered with a close up photo,...here...









What turned out surprising was that all the trains I ran through this route experienced NO derailments or noticeable problems with this short decreased radius track section,...even my Broadway Ltd 2-10-4 C&O T-1.


However the long driver 2-10-4 did NOT like to make the right hand turn after exiting the curved Peco (dbl curved) turnout. Its front driver would consistently jump the frog of that reverse curve.


All the other locos and cars did NOT have a problem here, even the long Bachmann northern 4-8-4 that ran over this route multiple times, slow-fast, fwd-backward, pushing-pulling those double auto racks.





















The 6 axle Proto E8 did not have a problem. That IHC tender did not have a problem once I substituted a better Peco short X.





Perhaps I forgot to mention that I replaced the 3 other standard Peco turnouts with the 'large radius size' verses the 'medium radius sizes' I originally sought to use.





I became so engrossed with making this particular route thru the double crossover work, that I forgot to test the other route,...the one with a more direct S curve. I will have to do that today.


I also discovered one other IMPORTANT item,....how lousy those metal track connectors are for transmitting electricity along the rails. They either MUST be soldered, or feeders run to every little section of track !!
 

beiland

Well-Known Member
#7
Second Stage of Testing


First order of business was to check that opposite cross-over route,...the one with just the two large Pecos on either corner of the short 24 degree Peco X. All of the locos, including a few new ones when thru this route with no problems. And the long auto racks as well, and that tender as well.


Next I decided to replace that short section of 22” curved track, along with the outer connecting track between the dbl-curve and the straight track portion of the std Peco. Interesting those 2 curved pieces need massaging together. I had to make the short piece of the inner route shorter than what I had yesterday in order to get a decent fit with the outer curve. Trying to utilize a short piece of flex track to make the short curve piece was a real pain in the ____. I'm seriously thinking of going back and redoing it with a short piece of 24” fixed curve track,...shortened to the proper length,...holds its shape better than the short flex track piece. (if the older 22”r piece worked find, then replacing it with a 24”r piece should be just find).


I then tested all those engines on these new curves, and everything within the double crossover system worked find.


Outside of double crossover system I had placed a right hand turnout connected to the other end of the curved turnout. That creates a S turn of its own. I had tried to utilize a 'med size' Peco there, and it caused a derail almost every time with my 2-10-4 steamer. I replaced that with a 'large size' Peco, and the 2-10-4 still has some problems on occasions. I'm going to recheck that tomorrow to be sure my memory is working correctly. All of the other locos and cars worked fine on either the Med of Large size Peco. I'll probably just end up using the large size Peco to be safe,... for this relatively more difficult spot to reach on my layout plan.
 

trailrider

Well-Known Member
#8
Question: Does your 2-10-4 have all flanged drivers or just the end pair? My kitbashed 2-10-4's (from Mantua Mikados) have only the end drivers flanged, with the blind drivers shimmed up .010" off the top of the rails, so they don't catch coming out of sharp curves. I try to avoid sharp S-curves for the sake of 85' passenger cars. Neat-looking track plan. Where the bottom of the flangeways are too deep, I add some ground plastic and solvent, and then file them back just deep enough to clear the flanges.
 

beiland

Well-Known Member
#9
My Broadway Ltd 2-10-4 did NOT have any blind drivers. Nether did my Bachmann 2-8-4 Northern. I think I may have found the problem.
 

beiland

Well-Known Member
#10
Peco Turnouts need flangeway shim (code100)


I thought it better to make this observation while it was fresh in my mind.


I decided to once again try running my 2-10-4 C&O T-1 thru the Peco curved turnout of my custom double crossover arrangement. It has NO problems with the 4 turnouts that make up the crossover itself. Where it has a problem is when it tries to turn off to the right after exiting the curved Peco. IF I use a MED size Peco to affect this right hand turn, the front driver on the engine derails everytime. If I use a LG size Peco things are OK. Here is photo showing all three size Pecos lined up there.






I experimented with putting a small straight section of track to proceed the rt hand turnout. It did NOT produce any better result,...same result as without it.







I do realize that the Peco CODE 100 turnouts do have curved tracks thru, and after their frogs, so that made me want to look at the radii involved. The MED size nominal radius quoted for Peco is 36". If my BL steam engine can negotiate its quoted 24" minimum, why can't it negotiate this turnout??


I am now convinced that what is needed is an old time recommendation for the Peco turnouts,....shim up the guard rail opposite the frog. That flangeway is too wide over there, allowing the axle on the locomotive to shift over just enough to make that leading driver wheel want to bump up over the frog point and derail.
 

beiland

Well-Known Member
#11
I decided to do another little experiment while I had this mock-up in place,...insert a SM radius right-hand turnout in there and see how that affected the locos. After all the SM radius Peco is quoted with a nominal radius of 24"r.


Naturally the 2-10-4 BL did not make it thru without derailing every time. My BL 2-8-4 did NOT make it thru. And now the Bachmann Northern 2-8-4 did NOT make it thru either.













Surprise, my older IHC 2-8-2 Mountain made it thru just fine. I think that is likely a result of its semi cookie cutter wheels on both the loco and the tender.









This IHC model came with 2 alternate tenders, the vandy and a rectangular. Both had those same wheels that had problems with those defective Peco X's I addressed earlier, but they sailed right thru this latest configuration with no problems.





All of my other engines, mostly 6 axle diesels had NO derailing problems with the SM rt-hand curved Peco that followed the curved Peco. Nor did the longer autoracks, or passenger car
 

beiland

Well-Known Member
#12
Update on Dble Crossover & Structure


I'm working on my outdoor helix track structure and the bridges that connect it with the interior layout. In that regards I have to jump back and forth with interior matters as well as those outside. One such item is that 'custom double crossover' and its connection with the helix tracks,....making sure I have the depths and sideways connections thoroughly thought out,...AND making sure I have the grade of the two in unison so as to not have vertical kinks/humps!


So I decided to concurrently finalize the track plan for that double crossover and build it on its alum bridge. I decided to investigate removing that little short section of curved track that I had been concerned about,...the one between the actual crossover piece and the dbl-curved turnout. WOW, it has worked out that I did NOT need that little curved piece.





To verify that things were still OK with fitting my overall plan for those spurs feeding the container yard, I laid this out roughly,..

Looks pretty smooth even with those medium size Pecos that follow up after the train exits the double crossover, (those Pecos will have to have their guard rails shimmed for the longer wheelbase steamers).


Now I need to fit that double crossover arrangement into my 6” wide alum base, and I need to provide a cut out in the side fence for the curved turnout to exit that alum bridge,..






Those round holes cut in the bottom of the base are for the Peco underneath style switch solenoids if so choosen.





With the turnouts taped in place to double check everything,..





Then with the whole structure in place,..







I have now glued a thin 1/8" layer of cork to that alum base and will like screw mount the turnouts in place with small #4 screws rather than gluing them down.


Interestingly I've discovered that these turnouts might even be manually operated via cable, but will wait until plywood decks are fitted into position to see if it makes any sense. Meanwhile I will go ahead and install the 4 turnouts with their Peco controls.
 

beiland

Well-Known Member
#14
I'm going to mount everything on that metal bridge piece of mine, and solder all the joints initially. Then I may have to come back and cut some 'insulating joints' in various spots to make the 'insulafrog Pecos' work on DCC.
 





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