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Explanation of icons in LFLSRM logo.
By Jeffrey G. Hook
The left icon of the logo, representing steam powered locomotives, is an outline drawing of what is known as the link of a Walschaert valve gear typically applied to a steam locomotive. By varying the vertical position of the radius rod, not illustrated, relative to the curved slot of the link, the locomotive valve events are made to occur such that the locomotive will move either forward or backward when steam is admitted from the throttle to the valves, cylinders and pistons. In addition, the vertical position of the radius rod will determine the point in the stroke of the piston at which steam is cut off from being admitted to the cylinders. For either forward or backward motion of the locomotive when the radius rod is positioned at either the top or bottom of the link slot the valves will provide maximum cut off or longest duration of admission of steam to the cylinders. Moving the radius rod toward the center of the link slot from either direction will shorten the cut off or diminish the duration of admission of steam to the cylinders.
See also Setting the Eccentric Crank.
The middle icon of the logo, representing a basic physical element of a railway, is a cross section drawing of a running rail as depicted in various drawings published in the American Railway Engineering Association Portfolio of Track Drawings, circa 1940. Numerous A.R.E.A. drawings and railway engineering principles have served as the basis for similar Deerfield and Roundabout Railway drawings and engineering principles.
The right icon of the logo, representing civil engineering of which railway engineering is a specialized discipline, is an out line drawing of a David White Company, Type II - U. S. Army Transit, Model No. 7020, built in 1952. Produced in accordance with specifications of the Engineering Corps,
U. S. Army, the instrument was recommended by the David White Company for "precise Municipal, Railroad and Bridge Work." The horizontal limb (horizontal circle) has a diameter of 6 and 1/4 inches and is graduated to 15 minutes (0.250 decimal Degrees), with two opposite double reading verniers to 20 seconds (0.0056 decimal Degrees). This instrument, originally procured by the author, has been used frequently to establish the surface and alignment of the tangent, curve and spiral tracks and special track work of the Deerfield and Roundabout Railway.
See also Circular Curve and Spiral Calculator and DRRY Drawing DRTRK12, Figure A, Standard Notation for Circular Curves and Spirals.
Image below of David White Company, Type II - U. S. Army Transit, Model No. 7014. Model No. 7020 is similar in appearance and equipped with detachable magnifiers used for reading the verniers.
