Standard for Rail Elevation

[dik]

Is there a standard for drawing rail elevations. I've attached a sketch with two approaches. The detailed one has a line for each transition in curvature. The simplified one has lines for the mid point of the sloped portion of the head and base. Is the simplified one common practice?

Dik

 

[francesca]

I wouldn't do it either way. The CL is not an axis of symmetry, so I don't know why you put it as a CL. You haven't labeled any of the fillet arcs, and none of what appear to be your dimension line extensions correlate to any meaningful geometry point.

I would've thought that a rail cross-section is a standard that belongs to the client, if not the over-seeing agency (so I would expect e.g. a single standard for all HSR in Europe).

 

[dik]

Thanks, francesca...

The CL is the centre of bolts for a 40# rail... I drew the lines close enough to show the relative points of the curves/tangents they represented, I thought. I didn't show any of the fillet radii.... Rail sections come with relatively standard dimensions and 'fittings'; they are not normally 'client' driven.

To draw all the points of transition as lines, leads to a 'cluttered' drawing as shown. I don't know if there's a standard manner of showing this. With W-Sections, I don't show the fillet lines and with S-Sections (I-Sections) I show the mid point of the tapered flange.

Dik

 

[MikeHalloran]

The mid-point of the tapered flange of an S section has some significance, as in roughly where any bolts go. Rails are not secured that way, ever, so there's no reason to show a gage line that's not defined.

In a simplified view, I show lines at the theoretical sharp upper outer corner of the flange, and the t.s.c. of the bottom of the rail head, but I'm aware of no standard.

In a detail view, I show lines wherever the curvature changes, as you have, just because it adds clarity and a bit of style. I also, sometimes, truncate all those extra lines, just showing them near rail ends, mostly so the pseudo-shaded rail doesn't dominate the view.





Mike Halloran
Pembroke Pines, FL, USA

 

[dik]

Thanks, Mike... no need to show them for the full length of the rail; even with thin lines, the rail was getting pretty 'dark'.

DIk