how would you???

[CSX5220]

Hello all-

Im in need of some help... I've been trying to (right to the "T") re produce Norfolk Souther's Altoona to Cresson section of mainline.

however Im in need of some good maps. I have an old Trains Magazine that shows some good pictures and some figures about the area, but thats not enough.

the information I have from the magazine is in Radous feet and in degree of curviture. How would one translate that to feet?

example is: 220 overall curviture
north side is 637 rad feet
south side is 609 rad feet
9 degree in curve 15 min travel time (rad 619)

thanks for the help

Happy trainzin
Mike S.

 

[Dermmy]

I can't help with conversions of the tech specs, but if you are just looking for on-line maps to use in conjunction with a mag article I usually use TopoZone.

There are other sources of arguably better maps, but i find the TopoZone pages load and scroll quickly, and if you select the 1:25000 and 'Large' view options there is plenty of detail. The maps are generally quite old, which can be good or bad depending on your era. One area I was checking out recently had the rail lines labelled 'Pennsylvania' 'Western Maryland' and 'Chesapeake & Ohio'....

Andy

 

[StorkNest]

With the various ways to do maps, you don't need to translate anything. Also depends on if you are doing a prototypical route or going off a model.

 

[RPearson]

...
example is: 220 overall curviture
north side is 637 rad feet
south side is 609 rad feet
9 degree in curve 15 min travel time (rad 619)

thanks for the help

Happy trainzin
Mike S.

Sorry I can't really help here. Railroads normally are layed out using circular arcs. Transition curves are usually added as lead ins to the circular arcs and the radius of the arc reduced slightly to accomodate the transitions. But the transition curves usually aren't indicated on the drawings.

The usualy practice to dimension the curve is to indicate a start point - point of curvature, PC - on the straight (tangent) track, the radius of the arc specified in degrees and minuites of curvature and the central angle of the arc specified in degrees and minuites of arc ending at the point of tangency, PT. The central angle is usually denoted with the capital greek letter delta and may also have an R or L to indicate the curve is to the right or left proceeding in the direction the track is layed out. Degree of curvature has a few interpretations depending on whether the surveyor used arc length or chord length to measure it. In the US I believe railroads use the chord method and road surveyors use the arc length method though older rr's also used the arc length method. Formulas are available if you need them.

Bob Pearson

Edit-
Using the arc length method R = 5730/D with R in feet and D in decimal degrees of curvature, gives R = 5730/(9+15/60) = 619.45 feet radius. So maybe the 15 min travel time is really 15 minuites of arc and rad feet is radius of curve in feet and the guy writing the article really didn't have a clue what degrees of curvature is.