I am recommissioning an old layout and am having derailing issues. Does it matter which way you run into a switch? I never thought so, but wonder if this might be causing my trouble.
Keith
There are several issues that can cause this. Wheels out of gauge. Track out of gauge. Turnout points not flush against the stock rail. Turnout frog worn. Turnout guard rails are incorrect or too shallow.
Yes it does. So much so that on the prototype they are configured so the straight option is always on the through route. In models entering from the two track end funnels everything to one track and can rerail a car. There are numerous problems that can be fixed. Where is the train derailing and what type of car or engine and where on the offender?
Frequently the MAIN LINE takes what appears to be the diverging route. Of course there is a difference between the Normal and the Reverse alignment and what would appear to be a diverging route.
The Levers in the interlocking plant and the home signals at the switch stand may say that you are taking the main line, but you will be going across the diverging route as far as the iron is concerned. If so (and NYCT does this all of the time) the speed limit across such a switch is still 10 MPH.
That is why levers and signals are referred to as “Normal” and 'Reverse." In this case a sign is posted at the switch indicating the speed for the switch, and you will only get a “Yellow over Green” from that home signals and never a “Green over Green”. On NYCT the lower signal head reports the position of the switch (Normal or Reverse) and the upper head tells of the next block signal.
Red = STOP
Yellow = Next Signal is RED – or this is a signal controlled by a timer. Speed (or the letter “S” for station) will be posted
Green = Next Signals is NOT RED.
However there are such things as Grade Timers, Station Timers and Wheel Detectors (a very nasty little signal) to contend with also. When these are in effect a speed number is usually displayed.
The Wheel Detector is particularly nasty. It is dwarf signal and always a Lunar aspect.
OFF = it is asleep and will not bother you.
ON = Your ENTIRE TRAIN must pass the detector at the prescribed speed or you will be tripped.
FLASHING = You are TOO FAST and must slow to the correct speed at once or be tripped.
Your locos should be able to negotiate switches from either direction. Check the gauge of the wheels and the gauge of the points and clearances of the guard rails.
Usually the straight routing of the switch is considered to be the normal route, but not always. Sometimes the curved route is the normal route.
Yes, it undoubtedly does matter which way you run through switches, but the dynamics are very specific to the system involved. By system I mean the materials, design, construction, and condition of the turnout, and also those parameters of the rolling stock presented to the turnout.
It could be drooping coupler pins snagging a guard rail. Happens to me on new rolling stock at times.
It could be couplers not able to swing in azimuth inside their draft gear sufficiently to keep the host car inside the rails. That’s a function of not only the coupler, but the degree of diversion, or the angle at the frog and the track beyond, whether they are straight or curved.
Are the guard rails doing anything helpful, or are they placed/worn in such a way that they constitute an impediment to reliable running? Many guard rails should be tighter to their mate-rail. Sometimes they are too close!
Is the frog filled? Maybe wheel flanges are riding up and causing sufficient yaw in the loose truck that the yaw include a nosing into the wrong side of the frog’s flange paths at the frog point.
The wheels on the rolling stock are not gauged properly.
Crandell
If the turnouts are functioning properly there shouldn’t be a problem. A have six turnouts on my layout, all Bachmann (one #5 and five #4’s). As many of us know Bachmann turnouts are notorious for causing derailments. I tweaked all mine to the nth degree and have very few problems with them, whether running point to frog, frog to point, main route, diverging route, it doesn’t matter. They work flawlessly 99.8% of the time. Remember, the real railroads occasionally have derailments on turnouts too.
I worked very hard to tune my turn-out so that it doesn’t matter. However, it would make sense that a train run at slower speeds when going into the diverging route.
Actually running all or at least most trains one direction only on a spcefic line is prototipical. In his college textbook on railroading for transportation planners The Railroad What It Is and What It Does John Armstrong (yes the famous model railroader) gives the example of paired track. The majority of the trains (no matter which railroad run railroad A’s line and WB on railroad B’s line EB.
Often the lines are in close proximity, but not always, for example the WP-SP paired track through Nevada.
Sometimes specific trains are run one direction on a given line. The example he gives: Railroad A operates a coal train WB from point a to point b. Instead of returning empty b to a, it goes north to point c where it is loaded with iron ore then returns EB to point a by direct route from point c that does not pass through point b.
The Western Pacific in the Feather River Canyon would run trains in one direction in the morning then, after a suitable break to clear the line, run in the other direction in the afternoon. This was so that they did not have to stop trains for meets on the grade, which although only 1% is actually very difficult (especially in starting EB trains) because of its length, the whole length of the trains is on the grade between Oroville and Portola with no level or down grades for relief.
One other possibility! Operators of three-rail AC powered layouts are accustomed to the switch machines automatically aligning a turnout to the proper track when the turnout is approached in the reverse direction. However, most two-rail DC or DCC powered layout have no such feature and you must make the effort to align each turnout your train approaches. I have had several visitors to my layout derail trains because they couldn’t remember to verify the alignment of each turnout before their train arrived. Those who own a three-rail layout are always the worst offenders!