Tubular track 1/2 + 1/2 = 1 plus

It has to do with the geometry.   One reason: The 1/2 straights (5.5 in.) back it so a simple figure 8 using o31 curves line up perfectly.

You'd need a time machine to go back and ask the original Lionel engineers.  My guess is that in order to make a half straight, let's say in "O" gauge track, the tie spacing would have to be changed and that would have been one more expense they didn't want to absorb or pass onto the customer.  

The October 2017 Vol. 63, No. 4 edition of the Train Collectors Quarterly has a great article, "Why Lionel 0 Gauge Track Dimensions Are What They Are" by Tom Myers. I found it a great and fascinating read, and contrary to some of the conjecture floating around, it is all mathematically based.

when does a half not equal a half?....................

From the 1954 How to Operate Lionel Trains and Accessories manual:

Also of note, the 020x 45 degree crossing is also a direct fit within a circle of 031 curves.  Each section assumes 45 degrees of the circle.

Other uses for half straights that are greater than half 1 regular section:

Dennis Holler posted:

when does a half not equal a half?....................

When I cut a pie in half and I get the big half.....LOL

I'm on a diet, I'll take the other half

Dan Padova posted:

Dennis Holler posted:

when does a half not equal a half?....................

When I cut a pie in half and I get the big half.....LOL

Hah ! Like I used to tell my kids when they had to share something to eat, "John, you get to cut the candy bar in half, but Amy gets to choose the first piece."  You'd be amazed at how precise a cut a 10-year old can make when faced with that situation.   

Another example of the sum being greater than its parts, happens all the time.

Bogie

OldBogie posted:

Another example of the sum being greater than its parts, happens all the time.

Bogie

Plus tax