In making notes and writing code for a turnout controller, I realized that I did not know what is standard, if anything, for referring to each end of a turnout.
There is a common track, and two switched tracks, right. The latter are often referred to as Main Line and Diverging, but I have sought in vain for a set of common terms like Common, Main and Diverge, or C, Y1 and Y2, or even Mannie Moe and Jack.
Did I just press the stupid button? Or have I just not read enough?
Thanks!
There is no standard that I know of for the names of the ends of the switch, as a turnout can be anywhere, that is, on a main line, in a yard, part of a wye, and so on. So, it all depends on your use, you could have ‘main’ and ‘siding’, or ‘switch lead’ and ‘yard track 3’ or whatever fits your situation. Of course, the parts of the switch (stock rails, points, closure rails, frog and wing rails) have names.
I suspect the issue is that, in prototype world, a turnout is something that goes onto a track, there are lots of named parts, but basically there’s the track (main line) and the turnout, in general. Oh sure, a wye might not look like there is a main and a siding, but in general, that’s how the prototype seemed to refer to things. So why name it?
Like the line about not naming a cat? Why name something that does not come when called?
In the prototype world, a switch (yes, they’re called switches in the prototype world. “turnout” is the result of model railroaders apparently being confused by the word switch being both a toggle switch, and a track switch, bit I digress) has a trailing and facing end, and a normal or reversed state. The “Facing” point is the direction headed into a switch when you have the choice of which way to go (either ‘normal’, along the main, or ‘reverse’, onto the diverging track) “Trailing” is the other direction.
Bob. This makes perfect sense. The interesting challenge here is that I am trying to describe the physical thing, the switch (I did not know that turnout is a non-prototype term) as a generic case. This is really more of a programming problem than a real one.
In real world, the thing is defined by its use. For my purpose, I cannot rename it based on which way the train is going. Not a big deal, was just hoping to make things clearer for the next guy (which could be me, if I forget what I did in the first place)
Well, I think you could name the three ends of a switch “Facing, Trailing, Diverging” and be understood. Facing being the single main, diverging being the siding, and trailing being the non-facing main.
For a bit more detail than you probably want, check out the wiki section on CTC.
http://www.largescalecentral.com/wiki/index.php?title=CTC
Particularly Part 1, “The Basics”
What I have seen used is A to B for the normal route; A to C for the reverse route.
BTW the mainline is usually the normal route, which can make things interesting since this may not correspond with “straight” like in the case of curved switches. the tighter radius which one would assume is in the reverse route can actually be the normal route.
Whichever way ABC should work, in that case as well.
Bob McCown said:Bob, Actually they are called both in the prototype. When I was working for the railroad you would "throw the switch" or the moving parts of the turnout. But you wouldn't tell some one to throw the turnout. Turnouts are referred to in the timetables as turnouts and listed as such "Turnout Speeds".
In the prototype world, a switch (yes, they're called switches in the prototype world. "turnout" is the result of model railroaders apparently being confused by the word switch being both a toggle switch, and a track switch, bit I digress) has a trailing and facing end, and a normal or reversed state. The "Facing" point is the direction headed into a switch when you have the choice of which way to go (either 'normal', along the main, or 'reverse', onto the diverging track) "Trailing" is the other direction.
But to get back to the point, about the names; I’ve always used “mainline & diverging route” (again that’s related to speeds; ie the main will be track speed, but the diverging route will be X). Or as in a yard, track number X,Y,Z, etc.
As a side note we had a unnamed official who thought it was possible to run through a facing point turnout…
Craig
From a computer programming point of view I think Bob has nailed it. The only discrepancy will be in 3-way switches and, as HJ pointed out, curved switches. For 3-Ways I would name the diverging routes Diverging-Right and Diverging-Left as seen from the Facing Point end. For curved switches, you just need to make a call as to which route you will name Diverging 
I think it can be boiled down to the direction the points are in. The points are either in the main position (that which is considered to be the mainline or through position) or the branch (the position the diverges from the main into a branch line somewhere else on the layout, an industry, etc.) position. The computer really does not care, it is only position 1 or position 2. A three way might be handled similarly, through - left - right, main - branch 1 - branch 2, etc. In the program, the names are only for the operators.
Bob C
In addition to the threeway switches and the curved switches there are single slip and double slip switches. All of which are much easier to handle when the routes run AB AC AD and so on. In order to keep the “next guy” informed a simple schematic will do the trick even for complicated trackage like double slip switches or double crossovers. One thing all switches have in common: one can occupy only one of the routes at any one time. 
Errrrr … I mean that’s how it works in my universe. 
I believe there is usually a through route, eastbound and westbound or northbound and southbound, and a diverging route(s) or siding. This would hold true whether a switch was a curved switch or not. In model railroading for electrical hookups there was always a point end and a frog end.
Well. All of this leads me to conclude that that I’ll set up the programming the way I need to, and add the prototypical or modeler language to any user interface that may come out later.
The interesting challenge is that I need to set up routines that do not care much about direction and main or whatever, even though, of course, that matters a lot to the actual track operation. A0 and A1 and B0 and B1 it is then. Unromantic, but workable.
The Jacksonville CSX Dispatcher can be heard referring to the East or West End of the siding. As in “Let me know when you’ve cleared the east end of the main at the Aviston Siding”
In North America, the default nomenclature is East and West, even when the track runs North and South. When I was a kid, this was especially confusing at East and West Winton Sidings, when they clearly headed north and south. The GN, and almost all RR in NA ran East and West, so it was the natural default position to label all things east and west rather than north and south. There are some exceptions, but they are rare.
Steve Featherkile said:To the best of my understanding, Railroads in North America are either designated an East/West Railroad or a North/South Railroad with eastern and northern traffic having right of way over western and southern traffic, all for getting the goods back to the New England Ports quickly. Nothing but, Railroad Operations Theory stuff to back it up, but it is in print this way in many places.
In North America, the default nomenclature is East and West, even when the track runs North and South. When I was a kid, this was especially confusing at East and West Winton Sidings, when they clearly headed north and south. The GN, and almost all RR in NA ran East and West, so it was the natural default position to label all things east and west rather than north and south. There are some exceptions, but they are rare.
I had read that east/west thing, and I hate it because of my minor dyslexia. That’s all fine for defining a route, but I’m just surprised that is no particular term for defining the twosies-end of a switch vs the onesies-end, regardless of orientation or which way a train is going.
Lots of other train things have names: the pilot (aka cow catcher) is in the front of the loco, whether it is heading east, west, north, or south. A frog sits at the junction of rails in the center of the turnout. Just a different way of looking at things, I guess.
Michael, it doesn’t get easier or clearer than A, B, C.
Yeah, that’s about where I am with it. A B C. Like I said, was just hoping that there were generic prototype or modeler terms. Nope.
I should have bookmarked that example; it wasn’t from a model railroader, it was some educational outfit.