I've been trying to figure out the uses for the half sections of straight and curved 027 tube track. Is there anything in writing that might explain where and when to use them? I just recently bought our first two 042 switches and constructed a passing track with them on a straight away. A piece of 042 curve brought the passing back in line with the straight track. Then two pieces of half track somewhere in the passing track and one half track in the straight through track seemed to work just right. Will that also work with 027 switches for a passing track?
And I noticed the half tracks are slightly longer than half a full section of straight track. So there must be a purpose in this madness.
Any other use for the halves of straight track?
And, what about the half curves. What are they used for? I see that two half curves together are longer than a full section of 027. And, are there such things as half 042 and 054 curved track?
I also got in a bunch of track I bought some other lengths of straight track. There must be a specific use for each of those lengths. I figured that I'd just find out what fits where when putting together different track arrangements but it would help if I had something concrete to refer to ahead of time to cut down on the trial and error method I'm now using. We don't have a permanent layout. A new one goes up each time the grand kids come to visit.
I appreciate any help on this.
Mickey
I can tell you that for an O31, O27 or O34 passing siding, a single reverse curve will match up with the main line and needs no special-length straights. That's the consideration that determines the relationship between the straight and curved sections. It works that way if the radius is the length of a straight section multiplied by the square-root of 2.
A straight section of O31 is 10 inches; so the radius is 10 * sqrt(2) = 14.142 inches. The radius of O27 is 12 1/2 inches; so the length of a straight section is 12.5 / sqrt(2) = 8.839 inches, which winds up being something between 8 3/4 and 8 7/8, depending on the manufacturer and when it was made. The same rule works for Marx O34: The radius is 15 3/4 inches; so the length of a straight section is 15.75 / sqrt(2) = 11.137 inches, which winds up being between 11 1/8 and 11 3/16.
Bob Nelson
Unless you do a computer layout, you probably are not going to be able to predict accurately when you need a short section of track. Trial and error works pretty well. I have been doing it for 60 years. With a little experience, you will find that you know when you need some short sections of track.
A few months ago, I bought a box full of cut sections of track, both curved and straight. It has been very useful. I dig through the box until I find something that will work.
Bruce Baker
Sometimes half sections of track work pretty well, you can open up a curve or put two or three half straights together rather than cut a track to fit. I have been using O gauge tubular track for years, I have tried a track plan a couple of times and got frustated with the track plan and ripped it up!! Track plans are for brand new track under ideal conditions.
I tried using K-Line's computer layout planner for Super Streets but it never worked like I wanted it to do, so I quit using track planning programs. Mainly I run trains for the fun of it.
Lee F.
Thanks all for your input. And, Bob, especially, as now it makes sense why the odd lengths of straight and curved 027 - 034 track. I wondered why they weren't to the even inch. Are the factory made half sections of straight track something that was made to go with the 042 curves as I still don't understand why they made them other than to just add another length of short track. But why aren't they exactly half the length of a full section of track. And I still can't figure out the half curves other than they allow for a different type of curve mixed in with some straight track. No big deal on this, just curious. Plus it's hit and miss when fitting in the crossings or diamonds. There had to be a reason for the length of track used in the 90 and 45 degree crossings. Can't figure that out either although it makes a difference what curves are used to bring the track around to the crossing. They can't make a length for every situation.
The crossings are made a certain size so that when you make a figure eight, you don't need any cut sections.
The O-31 sections are a little too small. You can prove this by taking two switches and a crossing and putting them together. There are gaps between the switches and the crossing. Put them together so the straight exit from the switch is connected to the crossing and the two curved exits are connected together. O-27 switches and crossings fit together properly.
If you lay an O-31 curve on top of a O-31 crossing, I think you will find that the crossing is a replacement for a curved section.
Many of us model railroaders love to lay out a new track design by trial and error because we are still kids at heart. What was fun 50 years ago is still great fun now! Currently, I am fine tuning the design of a whole new 6'x20' layout and the track is not yet secured to the table. Creating a railroad "empire" by hand is such a satisfying endeavor.
This might also be the time for me to upgrade from TMCC to Lionel Legacy and order that new Lionel Erie GP9 w/Legacy. I grew up in a house alongside the Erie mainline in northeast Ohio and have great memories of those Erie diesels that roared past the old home place all hours of the night!
I got curious enough to figure out the exact sizes needed for figure-8 crossings. There are three ways to make figure-8s with 45-degree curves:
The tightest uses 7 curved sections for each loop and a 45-degree crossing to connect them. To do that, the crossing needs to fit in place of a curved section in each loop, as Bruce noted. The length of the straight paths through the crossing are 10.355 inches for O27 and 11.716 for O31. Lionel calls their crossings 10 1/4 and 11 3/4, which are .005 short and .034 long, respectively.
The next tightest uses 6 curved sections per loop and a 90-degree crossing, with 4 straight sections on the arms of the crossing. The length of the straight paths through the crossing are 7.322 and 8.284. Lionel calls their crossings 7 3/8 and 8 5/16, which are .053 and .028 short, respectively.
These errors are all less than 1/16 inch; so Bruce is right that the "O-31 sections are a little too small." How much of a gap did you discover, Bruce? If more than 1/16, I wonder whether the various pieces are actually manufactured to the correct lengths.
It is also possible to make a figure-eight with 5 curved sections in each loop and a 45-degree crossing, with 3 straight sections on each arm of the crossing. However, the regular 45-degree crossing won't work here. Instead, you would need one with the same lengths as the 90-degree crossing, that is, 7.322 and 8.284.
I measured an O-31 90 deg crossing, and it is about 8.345. This measurement is with a tape measure. The gap is about 3/16, and I have 4 crossings in the layout. Each crossing has 4 switches connected to it, and the gaps are all about the same.
I didn't express myself very well in my last post, but Bob Nelson figured out what I meant, not what I said. I meant to say that a 45 deg crossing should match a curved section. A 90 deg crossing with 4 straight sections connected to it should be the same as 2 curved sections connected together.
I am surprised that Lionel didn't get this correct. The calculations are not hard. Maybe they did it by laying track on the floor. Who knows. It's lost in antiquity.
Here is more mystery. I just measured an 022 switch. The curved part is long and the stright part is short compared to regular track sections. I am once again amazed that Lionel didn't get this right. I have some prewar manual switches, and I am going to measure them. The error in the 022 switches is enough to account for the 3/16 gap I am seeing with the crossings.
This is the stuff I ran into when putting together our carpet layout. This is all in 0-27 track. I tried various combinations for 90 degree crossings. Plus I tried passing sidings. It wasn't too bad using 027 diameter track and switches but we're trying to use larger diameter curved track and switches for better operation. I still can't figure out what half straights and curves are for. Seems like there should be a specific function Lionel had in mind to make a specific arrangement of track. What I'm getting at is we will be putting up and taking down our floor layout periodically. I was hoping to have track arrangements that perform a specific function, ie, turn around loops, passings, crossings, sort of in mind using certain peices of track. Like a modular layout is put together. It's not a big deal as, like it's been said, part of the fun is just putting it together as you go along. So, my original question - did Lionel through out these half tracks for a purpose or just because.
Again, thanks for your thoughts and comments.
As far as I can tell, Lionel had no thought in mind when they made the half sections except the thought of making a half section. They are longer than a half section, as has been pointed out already. I believe they are longer so the ties are the same spacing as full sections and they could stamp the ties on the same tooling for both half sections and full sections.
IMHO, keep your hack saw or dremel tool handy for cutting sections.
Tinsnips!
I just measured a 021 switch which is a prewar O-31 switch, and the lengths of the curved and straight section are exactly correct.
I also measured a 8 3/4 45 deg O-31 crossing by laying a curved section on it, and it was correct as near as I could tell by eye. Bob Nelson's calculation of being 0.035 too long may be closer than I can measure using a track section. It is close enough that a person probably could not tell it wasn't perfect.
My experience with O-27 is that it is more accurate than O-31. It may be because it is newer, but the 022 switches were made after the 021s, and they are not accurate. Makes ya wonder.
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