I notice on my HO scale railroad that my trains are much more likely to derail on facing point switches than on trailing point. I’m not sure why this is…maybe it is because the points move slightly as the train crosses (after it HITS the points)…causing derailment. On a trailing point move it looks as if there’s no hitting of the points, and the trains’s weight also helps to force the points into a position that would avoid derailment.
Do real railroads pay attention to facing point verses trailing point switches i.e. favor one over the other or restrict the use of one over the other on certain lines?
On a single track main, trains run both directions, most of the time in equal numbers, so how can you favor one way over the other?
There are some areas that can take advantage of that: multiple track mains where there they favor right or left hand running; a mine district where the majority of loads are in one direction; a section of track that is part of a directional running plan. Otherwise the lay of the land and available right-of-way almost always determines which way a switch faces.
The other side of the coin is that prototype switch points are much more carefully shaped and fitted to the stock rails than any but the most painstakingly constructed model switch points. If some industrial designer suggested that switch points should be bent up out of sheet metal (like those of a model brand which will remain nameless,) he would off to a new job - flipping McDonaldburgers.
That’s what I thought. I was reading the classic “Track Planning for Realistic Operation” in which the author, John Armstrong, states on page 10 that facing point switches are avoided on mainlines for safety reasons.
In North American freight-railroad practice (Amtrak 79 mph) there is no restriction on facing-point switches on the main track. There is, however, a practice that the main track almost always takes the straight-rail route, and the side track, crossover, or siding takes the diverging-rail route. By “almost always” that means 99.99% of the time. About the only exception is the end of double-track where both of the tracks are of equal use (often one of the tracks is the “mainer main”). In that case, one of the routes has to be a diverging route. An equilateral turnout is sometimes used to split the difference between the two routes, but that’s more to acheive high speeds on both routes than to protect the points.
Signal systems and rules are particularly troublesome about the main track not taking the diverging route. It can be done but it takes a timetable special instruction to address it. It’s not a good idea as eventually someone will forget the special instruction, exceed the speed of the turnout, and derail.
Model railroaders frequently put the switch in backward, where the main track is the diverging route. John Armstrong talks about this in Track Planning for Realistic Operation, and diagrams it. By facing point, he means "div
As a teenager I was totally confused by Armstrong’s explanation of facing point. After I went to work for the railroad it became clear instantly. Sometimes Armstrong assumed too much railroad knowledge on the part of his reader, but that’s a small, small quibble. I still enjoy rereading his work, after the 20th or 30th time in some cases.
(In the Real World) I know i sometimes grind my teeth when im getting after it, and run across a rough facing point switch at high speed. Theres usually a howl from me or someone else on my crew as we get close, as long as the motors make it over it safely.[:)]
There is however a right and wrong way for switch handles to be mounted. On facing point switches, when lined for the mainline, the handle should be pointing toward in the direction of the two tracks. When the switch is lined for the siding the handle will pointing back to the single track.
The reason for this is so that if movements at speed on the mainline have anything dragging and happens to pass over the switch handle, it will not get caught on the handle and inadvertently throw the switch under the train.
You know, after 25 years in the railroad biz, I’ve come to respect model railroaders a little bit more. At least they can turn off the lights and walk away from it!
That’s somewhat true…but some of us modellers are tied to the transportation biz in other ways… I’m pretty much tethered to my business 24/7 and wish I could walk away from it on some days!
If that’s the malarkiest malarky you ever see, you’ll be lucky.
Obviously railroads use facing-point switches on main line tracks, but many? most? all? railroads do “avoid” them-- i.e. try to use as few as possible. Out here in the Bay Area, on SP’s Peninsula two-track main line, the tracks are signalled both ways but trains tend to run right-handed. Along with all the power switches there are a number of hand-throw x-overs between the mains, and I think they’re all right-hand x-overs – which makes them trailing-point for right-hand-running trains. Before CTC, in SP days, the center sidings were like that too: 2000-foot-long right-hand crossovers.
Well Timz,
If you ever decide to leave “Planet Peninsula”, you will find that not all RR’s have double track and even if they did, topography, where an industry can build and which way cars are to be picked up/delivered will dictate which way the switch faces.
BTW, over the years I’ve seen problems with frogs out number switch point problems by 1000/1 or more.
On a double track main facing point switches are avoided so that locals don’t have to perform “flying switches” to put a car into or retrieve a car from a siding. On single track mains this is not a problem as the local simply works that siding when traveling the opposite direction.
In the old days when double-track was current-of-traffic, that was important. Today there’s not much left, and where it is located, there is often very little wayside industry. Facing-point industry switches in CTC two-main-track territory are commonplace today. In fact, technically there is no such thing as a facing point switch in CTC multiple-main track territory, because trains operate in both directions on all tracks. Regardless, most railroads wtih CTC two-main track territory today tend to consistently operate most trains as if it was still 251 current-of-traffic, in order to maximize capacity. The direction that turnouts face is determined by local operating needs, geography, the industry’s needs, and network planning decisions. On a busy two-main track or single-track CTC railroad, most new industry switches are required today to be power-operated #15s so that trains can enter and leave on signal indication, and switching off the main track is forbidden for new industries. On high-density main lines, 10,000 acceleration/deceleration tracks are required enabling trains to enter on something better than a lunar indication. Many legacy industries still have hand-throws with electric locks, but for a new industry today, locating on a busy main line is an expensive proposition to buy the track and signal improvements requi