Helix Derailments, rare or common place

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Well-Known Member
I just finished building my helix structure that features cantilevered 'roadbed shelfs/tracks'.

These 'shelfs' are open to the center of the helix, and naturally I am concerned about the possibilities that trains would derail and fall into the center (the black hole....ha...ha).

What I am wondering is to hear of folks that have actually experienced such problems with their helix structures. Are such happening common place,...or rare instances??


Gomez Addams
Staff member
Stringlining is not at all uncommon, and it would be an extremely expensive disaster if it happened to a long train. A simple cardboard lip about 2 inches high, stapled to the inside edge of the shelf, will help keep things from plummeting to the bottom if they derail.


Well-Known Member
I agree with Terry that stringlining could be an issue. If those Auto-Max's overhang the edge at all, any type of barrier will be difficult. It's hard to tell from the picture. Traditional helix's with some inside supports offer a bit more protection. At least the entire train won't go overboard.


CEO ACME Corporation
Staff member
I would use a very thin pliable clear plastic no taller than the highest amount needed to prevent a rollover fastened with screws in order to be able to remove if maintenance was needed.

Not having anything there is just asking for trouble!


Well-Known Member
Okay let me tell of my one bad experience with a similar situation. It was NOT on a helix, but rather a tight turn on my old Atlas 'Central Midland' layout.

It occurred on a section of track that is the same as where this CSX train w fuel tender is setting,..

The train had come up a relatively steep grade (double mainline) and makes a 270 degree turn to go over that bridge.

Now imagine that I have my BRAND NEW Broadway limited 2-6-6-4 class A Norfork/Western articulated steamer sitting there instead of those CSX diesels. I had just gotten that engine in the mail the day before,...my first articulate loco & first sound loco.

I had a friend coming over to the house to pick me up to go to some event/party/whatever,..I've forgotten what. He was running late, but I wanted to give him a quick review of my new prize. So I lined the engine up there with a string of cars behind it,...just sitting in wait. I figured we could run down to the train room in the basement, I could cranked up that loco and pull the train across the bridge, and then we could turn everything off and get underway.

According to plan the engine cranked up fine,...sound and all, BUT I advanced the throttle too fast (straight DC). The engine feel off the track sideways (to the inside of the curve) and fell hard onto the concrete floor 4 feet below !!! I was devastated

I did a very quick pick-me-up and put things into a box, and any little parts I saw most immediately. I was too sick to stay there and lament the situation,...might as well just go to the party, then inspect things later.

Turns out things were not as bad as I first suspected. I guess I was just lucky in the manner it hit the floor. If I recall properly it landed on its wheels.

I have often thought back about why this occurred. Here are a few of my thoughts....
1) I believe it was the inside track it was sitting on. That track is mostly 18" radius track. Even if I don't remember correctly and it was the outer track, that one is primarily 22" radius track. That's awfully small radius (lots of resistance) for the train to be running on, particularly trying to start up on,...and quickly with my jolt to the throttle.

2) There was also lots of resistance to forward motion by the fairly long set of cars still trying to climb the grade up to that turn.

3) and of course my too heavy of a hand at the throttle.

Bottom line, that 'event' is still in my mind.
But of course I am now working with much bigger radius, and much less grade, and smooth track.


Well-Known Member
Staff member
The other thing you need to consider with the length and height of that helix, is the effect of a breakaway. Models can suffer coupling malfunctions too. You'd be amazed at the downhill acceleration rate of a long rake of HO cars.


Section Hand
I have a friend who has a N scale helix of approximately 1% and his helix ran flawlessly when I visited the layout and he ran two trains for at least an hour and a half.

The curves were wide and if I had to make a guess a 30 inch radius in N scale which helped make the helix bullet proof. The helix had a double track main line with one train traveling up the helix while the other traveled down.

I was impressed how well the N scale locomotives ran and the quality of their sound. He was a former HO scle modeler.

A well done feature.



Well-Known Member
I would use a very thin pliable clear plastic no taller than the highest amount needed to prevent a rollover fastened with screws in order to be able to remove if maintenance was needed.

Not having anything there is just asking for trouble!
I have several places on my layout where the track runs close to the edge of the "table", on the aisle. Train doesn't even have to be running if anyone walks by and knocks rolling stock off! In one place, I used a piece of floor trip screwed to the table. In another, there wouldn't have been enough clearance to get my fingers in to either re-rail or pick up a car, I drilled holes and inserted 4p finishing nails, spaced close enough together to prevent cars from falling over the edge. Nylon screenwire stretched between the nails would still flex enough to get my fingers in there, but not enough to allow cars to fall to the floor. That would look like a chainlink fence, too.


Well-Known Member
Playing with Ideas

I was out visiting a few hardware stores the last few day, and a Hobby Lobby,...walking the aisles looking for ideas. I'm particularly attracted to the use of Velcro type products and flat fiber/nylon belts. I've used some of these products in other manners before and been pleasantly surprised with their versatility,...particularly the HD commercial 'mushroom' style velcros.

So this evening I just very quickly put together a few ideas,...and took a few photos until my camera's batteries gave up on me,...under recharge now.

I found two brackets that I feel might be worthwhile. They are both 1.5" long on their legs. That 1.5 inches seems to be plenty long for resisting trains going over the edge.

So basically I was thinking of gluing those brackets onto the roadbed of the very top loop of the helix, then running a nylon cord around the perimeter of those fixtures, threaded thru the top hole of those brackets.

Or perhaps we could have a loop of this nice elastic flat 'rope' I found at Hobby Lobby ,...

It was very reasonable price, robust, and would not require additional securing other than its natural elasticity.

The outer face of the metal bracket might also be used to glue a piece of velco onto. That velcro could be the attachment of a vertical strip of flat ribbon material that would drop down to the bottom loops of the helix to prevent derails on those lower loops. Those protection straps could easily be released via their velcro connections at their bottom for track cleaning etc

.....just brainstorming


Well-Known Member
Packing Material Strips

Yesterday I was doing some reorganizing of my 2 outdoor sheds and ran across this item,....its a strip of some sort of foam that the house moving stores (U-haul, etc) sell for wrapping up glasses etc when someone is making a move, ...about 6" wide,....

Its very light weight, relatively strong, and non-stretchy. Perhaps attach some vecro type end fittings for vertical strips,..



Well-Known Member
Spaces between Vertical Strips

If I were to utilize vertical strips of some sort, I'm not convinced they need to be directly next to one another? I had written,..

I believe these vertical strips could be located a minimum of 6" apart. Most derailments are not going to occur as a single individual car dividing itself out of a consist to derail. Most derails I've seen are a string of cars trying to still stay coupled together while heeling over. And most engines that are going to try and negotiate the helix are going to be longer that 6 ".​


Well-Known Member
Videos of Derailments

Just for the heck of it I went looking for some videos of model train derailments this evening. Perhaps I'll do a little more looking as I was NOT finding that many good examples to post. Most of them were rather lengthy compared to the actual accident scene, but they did show how the trains tried to remain coupled together while derailing.

I did find this interesting 3D animation

Just found this one

Just found another on a long train running very fast in its helix. Look at time frame 10:55 for the BIG derailment !!
big spaces, but no cars or locos overboard

D&J RailRoad

Professor of HO
Wellll, lets see here.
I'm sure we have some on here who have 5 level, 15" radius helix with a 6% grade and they run their 80 car HO scale passenger and autorack trains up it all the time with a single blue box Athearn switcher with spud trucks. No video of course because they just aren't into that.
You have a conundrum there with your application. With no inside wall to prevent tip overs into the bottomless pit, you are putting your rolling stock at sever risk of sever damage. If you put a barrier you will prolly have to use clear plastic so you can see the wheels of the rolling stock to rerail any problems. The other part of derailments in the helix are run aways.
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