# Rail lengths and curves



## Jcutter (Dec 16, 2015)

I am laying my track out on the ground, trying to figure out the best route around trees, bushes, and structures. I tried this using RR-Track software but when I take it outside, it nowhere mimics my area. Most likely the result of poor surveying of the exact locations of objects and obstructions. When I lay the track out on the bumpy, soft dirt, it needs to be connected to get an accurate route set out. A problem emerged that creates some inaccuracies in this method: Each rail section, especially the curves, has a variable amount of rail sticking out each end with which to connect. If you push two curves together, there might be a gap in one rail or the whole connect occurs with one curve's rails pushed into the ties with no or minimum connect rail available. Each rail seems to be able to be pushed one way or another independently, resulting in different curves. I noticed that if I hold two brand new connected pieces of LGB R5 curves in my hands, curved downward, and push them together, I can make different diameters curves depending on which rail I apply pressure the most pressure. My question is, how do you know when you have the curves connected in their stated "15 foot diameter"? The same question comes up with long straight pieces as it seems that the rail ends are very moveable back and forth as are the tie locations. What should be their "resting locations"? When do you have to cut the rails to get the right exposed connection length? (Some of my track was purchased used so I worry that is has been altered but most of my concerns are with new track or when connecting an Aristocraft 10' diameter curve to an LGB 15' curve with all sorts of different exposed track end lengths.)
I need to be "standard" or "as advertised diameter" for planning as well as because the track will be placed on pre-formed Split Jaw PVC roadbed which will arrive soon and I just can't "wing it" with a railbender and adjust my roadbed after.

Any thoughts?

Jud


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## chuck n (Jan 2, 2008)

Carefully, measure the length of each rail on your curved track. The inside rail should be shorter. If you need precise lengths for your road bed you may need to trim the inside rail.

Knowing the length of the outside rail and the degrees of curvature, of that segment, you can calculate the circumference of the circle. Knowing that you can determine what the circumference of the inside rail should be. Then you can determine what the length of each inside rail should be. 

I'm not familiar with your Split jaw system, how does the track sit on it. Is it molded to receive the ties, or is it an open ladder that supports, but is not anchored to the track?

Chuck

I use that track and there is a lot of flexability in that circle. But it may or may not fit in a pre made base. That is, one of many reasons, why I float on ballast. If your base is that confining (?), how are you planning to handle thermal expansion and contraction of the rails?


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## Jcutter (Dec 16, 2015)

The track sits on top of the roadbed, not unlike the PVC ladder and you connect it every few feet. Each preformed piece has two or more holes ( on longer pieces) where the 3/4" PVC support pipes come thru. After leveling side to side and to your grade, two set screws secure the roadbed to the anchor pipes and the tops of the pvc pipes are trimmed even with the roadbed. The track is laid on top and screwed in. You leave some small expansion gaps before adding the final support strips across the joints of each piece. The roadbed is usually painted the color of the tie strips or ballast so as to be invisible. You backfill any showing roadbed and ballast.

As far as the rail lengths on the curves, shouldn't brand new LGB track have the correct lengths already?


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## chuck n (Jan 2, 2008)

Not in my experience. There are always gaps.

My suggestion would be to let the track sit on the bed for a while and see how is over a year. Then tack it down every 4' or so.

I knew someone in Denver who secured his track every foot or so. One hot day he came out and discovered that his rails were in the air and his ties were secure on the ground. Another friend noticed that his track moved several inches over the course of a year.


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## Gary Armitstead (Jan 2, 2008)

Jud,

You're making way too much work out of this. Track laying is not near that accurate in reality.....it flexes all over the place! Get yourself a dual rail bender and a razor saw. Cut the ends of the curve track so that you can install rail joiners or rail clamps. I am familiar with this Split Jaw system. I bought a couple of their plate deck girder bridges. Never used them and finally gave them away.

My suggestion would be to install your PVC track sections and then bend the track with the bender to follow and fit your PVC sections.


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## Semper Vaporo (Jan 2, 2008)

As I understand it, you are using "sectional track"... i.e.: track that is pre-assembled into straights and curves of fixed lengths and curvatures. If you assemble them correctly, they will form specific routes.

If you change (cut) just the inside or outside rail lengths then they will not form a smooth transition from one section to the next... i.e.: you will get "kinks" in the track that could cause derailments or excessive drag when the train passes over the transition from one track section to the next.

If you need to adjust the curvature then either cut BOTH rails to shorten the section of curved track and yet maintain the proper alignment between sections, or use a rail bender to adjust the curvature of a single section or a series of sections to fit the terrain the way you want it.

Changing the length of just one rail is a bad idea!


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## Jcutter (Dec 16, 2015)

I was pretty sure the answer was to purchase a railbender to not only get it to conform to the roadbed but also to make sure it's 45mm and flat. I already realised that on the sections where I had not planning to use the PVC roadbed, I would be better off to bend my rails and/or buy some Flextrack to make all the rails connect. The PVC roadbed is for the tracks thru the soft, pinestraw covered flower beds.


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## krs (Feb 29, 2008)

I think for a permanent layout Flextrack is the way to go.
That way one can incorporate easement curves which will be more realistic than the curves using sectional track.
I would also arrange the joints of the rails to be offset like on the prototype rather than straight across from each other the way they end up with sectional track.


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## Greg Elmassian (Jan 3, 2008)

I had a very tight area to fit my track, and I wanted to stay at 10' minimum diameter.


Sectional track and RR-Track software worked well, the software allowed me to do a lot of different "trys" of layout.

Surveying and accurate measurements of obstructions is EXTREMELY important.

Also the RR-Track program is pretty close to the actual measurements, but sectional track has give. One thing that does not make sense is you saying the ends of the curved tracks don't match, that is common on used track where it has been tweaked, but not new LGB track. In any case you can take a dremel with a cutoff wheel to trim the ends AFTER you have everything hooked up.

If you are trying to lay the track out on bumpy land, you will have additional issues, you need to level it, or do as I did, and bought some bags of redwood "bark" to "shim" the track to the level you want, easy to push into place under the track.

The picture below is my layout, the shape in the center is the house.... took some messing with to get it right, but much faster and easier with the RR-Track program.


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