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Depth Of Walthers Turntable Pit

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Depth Of Walthers Turntable Pit
Posted by caldreamer on Thursday, March 16, 2023 9:49 AM

Does anyone know the depth of the Walthers 933-2618 N scale 10' turntable pit?  I am planning on purchasing one and need to know the depth so I can set the code 55 track to match the track on the turntable.

        Thank You In Advance                                                                                                    

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Posted by richhotrain on Thursday, March 16, 2023 10:21 AM

caldreamer

Does anyone know the depth of the Walthers 933-2618 N scale 10' turntable pit?  I am planning on purchasing one and need to know the depth so I can set the code 55 track to match the track on the turntable.

        Thank You In Advance                                                                                                  

The depth of the pit shouldn't matter. What does matter is the height of the bridge. Your approach tracks need to match the height of the bridge track rails.

The bridge track doesn't extend to the lip of the turntable. It stops short, but barely. Your approach track will extend  onto the lip of the turntable and should leave a very slight gap without actually touching the bridge track rails.

Rich

Alton Junction

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Posted by selector on Thursday, March 16, 2023 11:08 AM

The pit of any scale or size still needs a clear aperture through the benchwork into which it must be recessed.  That is for the wiring to be attached from below.

The height of the pit's lip is what matters to you. The pit must be stable, so you need to consider onto what stable rim around the aperture you cut will out of the benchwork's surface the pit will rest. That determines the lip's final height, which in turn determines the heights of the approach leads rails. This is where you have to decide if you need to recess the pit a bit by scouring out the rim of the aperture you created to get it lower, or if you have to live with a slight grade on the approach lead.  I did the latter knowing that I was going to sprinkle the entire yard surface with sifted garden soil mixed with plaster anyway, which was going to raise the yard somewhat over the massive expanse (such as it can be on a sheet of ply). 

So, very simply, the pit needs a stable rest, and it is onto the top of the pit rim that you must rest rails.  I remove the ties needed to get the rails flat onto the lip, which also reduces the grade.  In fact, depending on the code of rails in the approach lead, you might have a bump there anyway with Code 100 rails resting on a gap where the bridge's rails are Code 83 or Code 70.  What I ended up doing was filing a shallow trench under each of my then Code 100 rails and glued them there.  This made the transition to the smaller Walthers bridge rails much better.

Take your time with this and think it through.  You'll not enjoy it if you make hasty choices.  It's the same problem as on either end of any bridge you install.

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Posted by sschnabl on Thursday, March 16, 2023 12:29 PM

Caldreamer,

I have the early version of this N scale turntable.  What brand of c55 track do you plan on using?  The reason I ask is that some brands are different.  My previous layout had Peco c55 track, which is actually c80 where .025" of the rail are buried in the ties.  As Selector did, I also removed the ties on the end of the track that approached the pit, and had to file a bit off the bottom of the rail since the bridge track is c70.  The ties were about the same thickness as the lip of the pit, so no shimming was needed there.

My current layout uses Micro Engineering c55 track, where the rails are .055" tall and the ties have a thinner profile.  I have added some .015" styrene to the bottom of the approach track rails at the lip of the pit to bring them up to .070 to match the bridge track.  I will also need to shim underneath the approach tracks since these ties are thinner than the lip of the pit.  As stated, you could also lower the pit a bit so the lip is the same height as your ties.

Good Luck,

Scott

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Posted by BATMAN on Thursday, March 16, 2023 1:12 PM

 

The pit goes in first and then you go about matching the approach, RH, and storage tracks. Matching track code to the bridge track through various means.

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by richhotrain on Thursday, March 16, 2023 3:02 PM

The bridge track is not going to be lower than the lip of the turntable. It is going to be level with the lip. So, depending upon the thickness of the ties on the approach track and the rail profile, the approach track will either match the height of the the bridge track or rise slightly to meet the height of the bridge track.

Rich

Alton Junction

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Posted by BigDaddy on Thursday, March 16, 2023 5:45 PM

BATMAN
The pit goes in first and then you go about matching the approach, RH, and storage tracks.

YesYesYes

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by caldreamer on Friday, March 17, 2023 9:51 AM

The reason I posted the original question was becaus I am using 1/2" foam plus 1/8" cork over plywood.  I need to know if I will need to cut a whole in the plywood so the pit will sit flush so that the with bridge track will mate with the approach and storage tracks. In other words, is the pit deeper than .875 inches?.

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Posted by richhotrain on Friday, March 17, 2023 10:23 AM

Ok, so your approach and storage tracks sit up 5/8" (0.625) off the layout surface. Once again, the depth of the pit doesn't matter. You can either raise the turntable up to meet the approach tracks and storage tracks by adding 5/8" of material under the lip or have your locos descend 5/8". 

Arranging for the locos to descend is probably not practical since the storage tracks will be short in length. So, your best bet is to raise the turntable 5/8" by adding material all around under the lip. I did that on my last layout where the roadbed was 5mm thick.

Rich

Alton Junction

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Posted by AEP528 on Friday, March 17, 2023 10:33 AM

The question is: Is the turntable pit taller than the sum of the foam and cork? If so, he needs to cut a hole in the plywood. If not, he doesn't.

He doesn't seem to asking a very hard question. Can anyone provide an answer instead of telling him he's doing it wrong?

 

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Posted by richhotrain on Friday, March 17, 2023 10:42 AM

AEP528

The question is: Is the turntable pit taller than the sum of the foam and cork? If so, he needs to cut a hole in the plywood. If not, he doesn't.

He doesn't seem to asking a very hard question. Can anyone provide an answer instead of telling him he's doing it wrong? 

If that is the question, then he should state it that way. I have not understood it to be the question. Perhaps you can provide an answer!

Also, a hole needs to be cut to provide space for the circuitry attached to the bottom of the turntable. You can't just sit a Walthers turntable on the layout surface.

Rich

Alton Junction

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Posted by caldreamer on Friday, March 17, 2023 7:47 PM

The question is: Is the turntable pit taller than the sum of the foam and cork, .625 inches? If it is I will need to cut a hole the diameter of the pit to allow the lip to sit so that my approach and storage tracks will be the same height as the bridge track. If it is not then a hole large enough to connect the circuitiy will suffice.

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Posted by richhotrain on Friday, March 17, 2023 8:24 PM

If you don't cut a full size hole, you risk instability. The turntable will likely rock back and forth. Bad idea.

Rich

Alton Junction

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