Curves without easements, do they exist?

[mudchicken]

From my Civil Engineering Hand Book -

Railway Spiral Curves. Transition or easement curves are used between tangents and circular curves on main-line railroad track to provide a satisfactory means of attaining the super elevation and to avoid an abrupt change in alinement. The Spiral curve, defined by the A.R.E.A. as “a form of easement curve in which the change of degree is uniform throughout its length” has been generally adopted.

So - yes a Spiral curve is an easement. You can call it either one. Easement curves are spirals.

On the D+RGRR drawings I have the centerline points are described as-

PS - point of spiral

PSC - point spiral to curve

PCS - point curve to spiral

PT - point of tangent

But on one the drawing I have there are simple curves with just a PC and PT, point of curve and point of tangent.

Steve

Don’t make me come over the continental divide and wash out your brain with soap. (Oh wait, we’re already over there…including right now in Delta[:-,])

If all Steve has is the Val Map for the North Fork Branch, he’s already in trouble (0. 855 feet off because of the narrow gage shift from when it was built between 1902 and 1906)- Better know where the GLO filing map is. We’ve seen plenty of blunders by surveyors all three directions out of Delta, including Delta to Sommerset.

AREA (It’s been AREMA since 1996) started because the civil engineers (ASCE), including that Searles clown, lost their grip on practical reality. That AREA 10-Chord spiral was adopted from the Talbot 10-Chord Spiral (Talbot’s books and reports are an AREMA staple to this present day)

Arthur Ridgeway (sharp cookie) was more of an operating bubba by the time he signed that Val Map. (His RGS and Moffat Road engineering days