3RP48: Converting O27 track?

[Jumijo]

Thanks for the responses. Yes, O27 and Proto 48 go together like bacon and ice cream, but is it really the most warped idea you've seen in a train forum?

Nuts and gum, together at last!

[trigtrax]

I think you should look into MTH Scale Trax.

[lionelsoni]

Sorry, Roger; it's a repeating decimal (26.92708333... = 2585/96).

[Dave Farquhar]

Thanks for the responses. Yes, O27 and Proto 48 go together like bacon and ice cream, but is it really the most warped idea you've seen in a train forum?

Admittedly, Bob's answer tempts me to try it. Almost.

[gvdobler]

Look how many times 27 appears in the 27 digit version.  That has to mean something.

[envfocus]

Well, if you are really going to be serious about this, the least you could do is use the appropriate number of signficant figures.  If you are going to talk about 027 curves, then clearly you must carry out your calculations to 27 digits.  So the obvious answer is 026.927083342927827727627127 or not.

[lionelsoni]

Mel, it's the diameter to the outside ends of the ties.

Dave, .057268616 and .028634308 inches, respectively, more or less; although it might not be necessary to move or shorten the center rail at all unless your pickup rollers are right on the edge.

Those numbers are for curves that have 8 pieces per circle (O27 and O34).  For O42, you need .038179077 and .019089538.  For O54 and O72, .028634308 and .014317154.

The ties are an interesting consideration.  At 2 inches, they are a reasonable prototypical length of 8 feet.  However, simply moving the center and inside rails outward leaves the ties off center by a whopping .036458333 inches.  This can be avoided by moving the outside rail in and the inside rail out by the same amount, .036458333 inches.  The lengths by which to shorten the inside and center rails, however, remain the same as given above.

The purist will also want to redesignate the nominal track size, so as to be able to distinguish between ordinary O27 and the Proto-48 version.  The obvious solution is "O26.92708333".  Or not.

[Jumijo]

 

Dave...Dave...Dave...

[RRCharlie]

Dave;

I am getting ready for night class so don't have any track with me and I have forgotten a few things. For O-27, does the 27 inches refer to the outside diameter of the track at the outside end of the cross ties, the outside diameter of the outside, middle, or inside rail?

Mel Hazen; Jax, FL

[palallin]

OK, I'll bite, despite the fact that I cannot conceive that this question is seriouly meant (Proto48 O27 has all the ahllmarks of real faux fur).

Move the rails to their new positions, and wack the extra length off with a cut-off disk.

I have to ask, though, how you narrow the gauge on the metal ties.

[Dave Farquhar]

The track gauge of 1.25" is really starting to bother me, so I think 3-rail Proto 48 is an idea who's time has come. Proto 48 uses a track gauge of 1.177 inches, which is 4'8.5" in 1:48 scale.

Converting O27 straights to the P48 width is easy. The problem is my O27 curves.

How much would I have to shorten the outer and middle rails so I can make a circle of Proto 48 3-rail O27 track?