Fastrack curve sizes

[Anonymous]

Where are the FasTrack circle curve sizes measured from to get there size of 036,048,etc? Outside rail to outside rail, center rail to center rail,inner rail to inner rail or road bed to road bed?

[LS1Heli]

It has nothing to do with the roadbed. The diameter is the diameter of the curve that the engine is physically making. Outer rail to outer rail.

[Anonymous]

Thanks much.

[Anonymous]

An O36 circle will take about 40"including the roadbed.

[ADCX Rob]

QUOTE: Originally posted by LS1Heli

It has nothing to do with the roadbed. The diameter is the diameter of the curve that the engine is physically making. Outer rail to outer rail.

LS1Heli,

Unfortunately, to confuse things even more, Lionel has actually designed the Fastrack system to be measured center rail - to - center rail. The O36 section circles are precisely 36" in diameter measured center rail - to - center rail, and the roadbed is 3 11/32" wide, so a circle takes up 39 11/32", or just shy of the 40" as Houdy indicates.

One problem with the Fastrack geometry is that the "O36" straights should be 12.73" long, the 90 degree crossings should be 10.54" across, and the 45 degree crossings should be 14.91" across. If this were the case, you wouldn't need so many small "fitter" sections for standard track layout configurations.

Rob

[lionelsoni]

From an old thread:

I stopped by a hobby shop on the way home from work and measured a piece. The center rail distance was very close to 13 2/4 inches, which works out to a radius of 17.965241 inches, or very nearly 18. Working back from the radius to the chord gives 13 25/32 inches, only 1/32 more than I measured with the old yardstick that was at hand. So, obviously, the diameter is meant to be 36 inches between center rails.

(The roadbed is 3 3/8 inches wide. So Roger's measurement is very close to the outside diameter of 39 3/8 inches. If Lionel had named fastrack in the same way they do tubular track, it would have been called O39.)

[darianj]

QUOTE: One problem with the Fastrack geometry is that the "O36" straights should be 12.73" long, the 90 degree crossings should be 10.54" across, and the 45 degree crossings should be 14.91" across. If this were the case, you wouldn't need so many small "fitter" sections for standard track layout configurations.

WOW...Someone was really paying attention in Geometry![tup]