In reading the latest publication Dream Trains 2. I have begun to notice that crossing diamonds are not always symmetrical.
My question is are diamonds made to a specific angle or is the track laid to a standard angle to the crossing?
Unlike model railroad “snap track”, railroad diamonds are built to the angle of the crossing, which may vary all over the place.
There probably are some standards that they try to meet (which would greatly simplify replacement parts).
As always, glad to stand corrected.
I’m not sure I understand your question, but if this helps…on model railroads we’re used to adjusting our trackplans (unless we hand-lay all our track) to use pre-made commercial crossings in set angles like 90-degrees, 45-degrees etc. On real railroads, there may be situations where they can use pre-formed frogs and such but generally they’re building each crossing to meet the specific situation and purpose.
Crossing frogs are custom built to a specific angle - and radius or radii, if need be.
In 1982 I was in charge of a little project to replace a crossing frog at the then-B.F. Goodrich plant in Pedricktown, NJ (roughly opposite Wilmington, Delaware). The original installation was a cobbled-together affair from an old crossing frog that the serving railroad or contractor then just ‘had on hand’, in the approximate shape of a flat ‘X’ - except that both routes were curved pretty sharply, with radii in the 350 ft. = 16+ degrees to 500 ft. = 11+ degrees range, as I recall. and an angle in the center in the range of 75 degrees. I had to establish the detailed geometry of both routes to figure all that out; order the thing - a ‘rail-bound’ manganese steel casting type, if I recall correctly - from the then-Bethlehem Steel Co.'s ‘Frog & Switch Shop’ at its Steelton, PA plant; then carefully and thoroughly check the fabrication and assembly ‘shop drawings’ to make sure they understood all my sketches and geometry correctly - they did; and then stake it out and supervise the installation during a 1-week plant shutdown after the 4th of July holiday - and yes, it all fit just fine.
Any of us with some experience in th
The track alignments of real railroad are dictated by the geographical nature of the line they are trying to follow. Most current alignments were laid out in the 19th Century when Irish and Germans with pick and shovel, black powder and mules hauling wagons were state of the art earth moving technology. A consequence of this technology is that where lines crossed each other could be on virtually any angle between 1 degree and 90 degrees. Each crossing diamond is unique, from the angle of the crossing, from the tonnage carried, from the number of tracks involved in the crossing. Replacement of diamonds is a big engineering project as to do the job properly requires a ‘hardening’ of the ground structure where the diamond exists as every train passing over the diamond creates a multi ton hammer blow each time a wheel impacts the far end of the flange-way.
(1) Custom made, very expensive rascals, you avoid them at all costs
(2) Very brittle…darned near come with welders to fix them.
(3) Standard parts aren’t (custom trackwork)
(4) AREMA has detailed standards (in a general sense), dictated by how skew the crossing is. (the closer to 90 degrees, the better off you are)
(5) Railroad engineering departments keep detailed files on the crossing history and how often they are replaced. Some crossing frog files that I have worked with went back 120+ years.
(6) Asphalt under the crossing and drainage are serious issues. Mud in the crossing is an early death for that trackwork. Track and signal forces get into some interesting tussles over what goes on at the crossing.
(7) Paul was probably dealing with a rigid rail bound maganese (RBM) crossing frog with manganese inserts (explosive hardened). Rigid carbon frog (machined from rail pieces) installations usually show up in light tonnage applications unless you need a replacement in a hurry.
(8) Figure a minimum of 6-9 months from placing an order to gettting and installing a replacement frog. (good measurements are a must - why surveyors get called in to verify the angle and the curvature in play…)
(9) All those pieces and parts sitting nearby are there for a reason. The darned things break! Being custom made; you try to keep extra parts, inserts, bolts at the ready. Often, a diamond shows up with 5 or 6 inserts (1 or 2 spare)… The previous worn crossing is often hanging out in the weeds in case of a major crisis (such as a derailment) where a band-aid can get you through until a replacement can be made. Roadmasters will be obsessive around crossings especially dealing with bolt tightening, washers, special otm , ballast surfacing and the ties that support the diamond. The more rigid the ass