I know the common causes of derailments but I just found a cause I had never run into. Does a comprehensive list of causes of derailments exist. In other words if you cant find a cause due to the expected reasons try these.
Normal things to check are;
Track gauge
Track level (Longitudal and across)
Mismatched rail code causing bump or drop.
Rail joint not tight.
Track obstructions (on or near) Nails, scenery, buildings bad weld or joint.
Turnouts (not level, improper gauge or wheel clearance at guand rails or frog.
Curve radius too tight
Wheel Gauge or width off
Coupler height (coupler and trip pin)
Here are some things i have found that are less common but still cause derailments;
Trucks are deformed (wheel(s)) don’t all sit flat on track.
The Steam loco is connected to the tender by the cable but the bar is disconnected.
A piece of a loco detail or rolling stock has come off and is on track or causing wheels to lift.
Switch machine too close on curve causing loco plow or other body part/detail to hit.
Turnout points not firmly contacting stock rail (both sides)
Turnout points not shaped right to fit stock rail at top of points
Poorly adjusted truck movement on rolling stock
Steam loco lead or trailing trucks not sprung properly
Steam loco floating / sprung drivers not properly sprung (too strong or weak)
Diesel loco wheelsets just a tad out of gauge. The flanges should be centered in the NMRA gauge slots, not just sorta fitting into the slots.
I’ll second the one on the track level across the rails, including at turnouts, which can readily be a bit twisted. Part of this is how level you first make your roadbed and, related, how much you choose to glue down the turnout, often avoided for maintenance ease.
Oh, and running a train into a turnout from the diverging direction with the points thrown wrong. I’ve heard this can happen.[;)]
A kink in the track. One might think that would show up with a gage check. But maybe not.
Another one I ran into back in the day was when my club had trackwork where they built the main higher than the sidings. Admirable, actually. But they had the grade change for the siding happen “inside” the switch. Very bad. I jacked up that section of the siding until the track was again fully parallel to the main before starting a grade change. I’ll call this “Grade Change in Track Switch”.
And a variant on the above: Sudden Grade Changes. I/we run into that at Free-mo where there’s been problems at the ends of modules where the foam shrank and lowered all the track except at the end that sits on plywood. As I have watched trains cross these problems, I am amazed at how many cars actually make it.
It didn’t cause a derailment, but it sure was irritating. I ran my new Bowser C-628 on a train. As I say, irritating. Turns out the snowplows (yes, one at each end–SP) had near-zero* clearance from the rails. Yup, I’ll be a-fixin’ that. Otherwise, a beautiful loco. So, I’ll put this down as “Dragging Equipment”. Also happened on a $500 brass passenger car.
Ed
*I just measured the clearance: .005" to .010"
PS: Looks like Paul got some of mine while I was clicky-clacking.
Wheels both in gauge, but slipped toward one end of the axle so that, when tracking, neither axle’s wheels are directly behind/in front of their counterparts on the next axle;
Axles not seated properly in the trucks’ bearing cones;
Sags or humps leading through the points and toward the diverging leg of a turnout;
Frog poorly designed or made allowing wheel drop or improper tracking;
Points rails not sharp enough;
Wrong tire and flange profile for the NMRA-compliant turnout;
Couplers that aren’t really compliant or suited for matching;
Couplers that aren’t mounted suitably for the curvature radius being used;
Improperly installed pilot trucks on steam locomotives!
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This was almost enough to make me go all diesels. Now I only operate Spectrum, PowerHouse, or brass locomotives. These all seem to work well. On many steam locomotives the pilot truck cannot pivot freely, has tension on it, or is just way too light to stay on the rails.
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On most locomotives there was not a good option for fixing the problem.
Turnout not reset to proper position. (left switched to siding or spur).
Turnout switch points dance around, not held in place by ground throw or switch machine.
Turnout directly after curve causing a S curve.
Turnouts too tight for longer locomotives or rolling stock.
Loose ballast in a turnout.
Wheel sets not properly set in trucks.
Coupler ‘brake hose’ too low.
Automobiles or livestock on track.
Bridge painter falls from bridge, is dragged 500 scale feet by a freight train, and the train derails. Painter is discovered beneath the locomotive, dusts himself off and continues work on the bridge.
Hasn’t been a problem for me. I installed two leading and one trailing two-wheel trucks on my logging tanks with no weight or springs. No derailments.
And, in general, I’ve not noticed lead truck problems on my steamers. But mainline steamers have always run on 36" curves and up. Even my loggers have a min radius of 18".
I do wonder if the leading truck problem, at least for two wheel trucks, for long wheelbase locos on sharp turns couldn’t be that the lead truck wheels go out of tangent with the rails.
This list when finished should help a lot of model railroaders that cant figure out what is causing a derailment. I’m also going to add that the cause may not be the site. Often the loco or car derails a good distance before it becomes obvious.
