Example Output Picture

Railroad Easement Templates

When laying out railroad tracks, surveyors use spiral easements, also called railroad curves, to connect tangent (straight) track to curved sections, and to connect two curves of differing radius. The easement is a curve of smoothly varying radius. On the prototype, easements minimize the sideways lurch of entering or leaving a curve, and provide a means to smoothly blend in superelevation (banking). On the model, easements will minimize coupler and diaphragm mismatch on entering and leaving curved track.

The two files (English and metric units) presented here provide a printout of railroad easement templates on PostScript printers. They are based on the "chain and offset" surveying method explained in the October 1969 issue of "Model Railroader" magazine.

The files are plain text, which can be sent to any PostScript-compatible printer. The user settings in each file, which are shown in bold here, may be changed for the desired size and direction of easement, using a text editor. After editing the user settings, save the file (be sure to use plain text mode) and copy it to the printer port to which your PostScript printer is connected. The program takes care of pagination and, for multiple-page printouts, prints alignment tick marks at the corners of the page. It prints radius and length on template, and calls out "tangent/spiral" point and "spiral/curve" point.

To preview the program output on your computer screen, or to translate PostScript output to other printer languages (e.g. Canon Bubblejet) you may use a PostScript interpreter such as the excellent freeware Ghostscript available at the Ghostscript WWW page. Executables are available for Unix, DOS, Windows, OS/2 and Mac.

The English-unit version

EASEMENT.PS This version uses inch measurements on letter size paper.

Starting in line 14, edit the "user settings" for your desired easement:

%user settings:
/radius 24.0 def %change 24.0 to your curve radius in inches
/length 18.0 def %change 18.0 to your easement length in inches
/lefthand true def %change to false for right-handed easement
%End of user settings

The Metric-unit version

EASEMET.PS This version uses millimeter measurements on A4 size paper.

Starting in line 15, edit the "user settings" for your desired easement:

%user settings:
/radius 600.0 def %change 600 to your curve radius in mm
/length 450.0 def %change 450 to your easement length in mm
/lefthand true def %change to false for right-handed easement
%End of user settings

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