All the things that cause derailments.

[gavino200]

Before I start building my new layout, I want to think a bit about what are the pitfalls for derailments that I can avoid. I've discovered a few of these over the years, but I'm sure there are many that I don't know about. So if all y'all could help me crowd-source this, I'd greatly appreciate it.

 

Track design related

1. Chicanes, aka S curves. - Curves in opposite directions jointed together

Solution: Eliminate them or place a straight piece between the curves

Solutions from @Cat

For Track issue #1, my list for the length of straight between S-Curves in order of ideal preference:

1) Length of longest piece of equipment over couplers.

2) Length of longest piece of equipment's wheelbase from outermost wheels.

3) Length of longest two bogies coupled together.

4) Length of one longest bogey and coupler.

5) Argh, very slow speed operations only and make sure it is an easy to reach location.
 

 

2. Radii that are too tight for particular trains.

Solution: There's a specific radius that you shouldn't go below for Shinkansens. Anyone know it?

There's a specific radius not no go below for large steamers. Also anyone know what it is?

Solutions from @Cat

For Track issue #2, I like to do a 'fake easement if space allows — putting even a very short section of a wider radius turn at the ends of any curve.  This gives a big visual improvement too with reduced jerkiness of motion.

 

3. Long rakes of turnouts in yards

Solution: place short straights between junctions. Though this does add a lot to the overall size of the yard.

 

 

 

Track related

1. Kato #4 Turnouts

Solution: File down the rail to allow the moving rail to seat better

 

2. Kato #6 Turnouts - less of a problem than the 4s but still a bit problematic

Solution: possibly the same, though a more difficult correction.

 

3. Kato Double and single crossovers

Solution: Could the same solution help. I've never dismantled one of these and I think it would be difficult but it's worth a try.

 

Possible solution is to just switch to Peco track which seems to have a great reputation for been derailment bulletproof. Though a complete switch is expensive you already have a ton of track.

 

 

Train Related

1. Bogies that become stuck for whatever reason

Solution: Find the problem and fix. Or replace the part.

 

2. Articulated coaches with bad connectors. Morning Daylight springs to mind.

 

3. Rolling stock with old fashioned pizza cutter flanges. Rarely a problem. Though my only Dapol loco seems to have more trouble than any other loco with turnouts. I wonder if some brands are still problematic with Unitrack.

 

 

Serious Question

Is it possible to design and build a layout so well that a derailment is really an unusual event? Has anyone here achieve this? If so, how?

 

 

Edited March 21, 2022 by gavino200

[Cat]

For Track issue #1, my list for the length of straight between S-Curves in order of ideal preference:

1) Length of longest piece of equipment over couplers.

2) Length of longest piece of equipment's wheelbase from outermost wheels.

3) Length of longest two bogies coupled together.

4) Length of one longest bogey and coupler.

5) Argh, very slow speed operations only and make sure it is an easy to reach location.
 
For Track issue #2, I like to do a 'fake easement if space allows — putting even a very short section of a wider radius turn at the ends of any curve.  This gives a big visual improvement too with reduced jerkiness of motion.

[gavino200]

Thanks Cat! I'll add those!

[gavino200]

45 minutes ago, Cat said:

 

1) Length of longest piece of equipment over couplers.

 

 

 

Do you mean the length of the longest piece of rolling stock measured from front coupler to rear coupler?

[Yavianice]

After building a layout with all the safety precautions (62mm straights between corners and any kind of point, only large #6 points on the mainline, only S curves with a straight of at least 124mm (preferably more) in between it, using "large" track pieces (e.g. 1 long straight instead of multiple short ones), not running trains TOO quickly (especially down ramps at full speed), and taking good note about connecting super-elevated track properly (must be the #1 mistake I see people do when complaining about derailments on Zuckerencyclopedia), I do not get derailments at all. But then my track is a folded dogbone, and in that aspect not so "complex". 

[bill937ca]

Ballasting at turnouts can cause grief. Keep the moving parts free of obstructions.

[Cat]

2 hours ago, gavino200 said:

 

Do you mean the length of the longest piece of rolling stock measured from front coupler to rear coupler?

Yes.  Derailments on S-curves are caused by torque when one car is twisting in two directions at once.

[inobu]

5 hours ago, gavino200 said:

Serious Question

Is it possible to design and build a layout so well that a derailment is really an unusual event? Has anyone here achieve this? If so, how?

Yes,

 

Sound Track Geometry, switches the lie flat, super elevated turns and insure that the track doesn't creep.

 

The important point in this video is the sound of the wheels. The sound of the wheels reveals how well the track is laid. 

 

The first video show gravity pulling the car. The second is a push. 

 

 

 

 

 

 

[gavino200]

5 hours ago, inobu said:

 

Sound Track Geometry, switches the lie flat, super elevated turns and insure that the track doesn't creep.

 

What's track creep?

[inobu]

1 hour ago, gavino200 said:

 

What's track creep?

When the track is not secured to the roadbed the track can move. Sometimes it will teeter back and forth or rock.

This is more prevalent issue in N-Scale. 

 

That is one of the factors with the Kato switches. We don't want to glue the switches in place so they pitch. When the pitch to the outer rail it

causes the wheel to pick the rail. 

 

Inobu

[bill937ca]

2 hours ago, inobu said:

When the track is not secured to the roadbed the track can move. Sometimes it will teeter back and forth or rock.

This is more prevalent issue in N-Scale. 

 

I've experienced this with track leading to a tunnel portal. Before ballasting the clearance was good. After ballasting the track shifted just a bit and some trains didn't celar the portals.

 

[gavino200]

5 hours ago, bill937ca said:

I've experienced this with track leading to a tunnel portal. Before ballasting the clearance was good. After ballasting the track shifted just a bit and some trains didn't celar the portals.

 

That's interesting. It makes sense. You're pouring a lot of water based glue over dry wood chips or something similar.

 

I was watching a Peco video tutorial on ballasting a few days ago. They advised firmly fixing the track to the board, before ballasting. It seems like this would prevent the issue you're talking about, but I'm just guessing.

 

I'm actually not the biggest fan of ballasting. I've never done it. It seems like it would generate a ton of excess debris that would get everywhere, like inside gears and such. Also, I'm not sure I actually like the way it looks. I think I prefer the clean plastic appearance of the Kato Unitrack. Weird right? But if I end up using some Peco track, I'll have to ballast as the Peco track looks pretty silly without ballast.

[bill937ca]

With roadbed track like Kato and Tomix I think painting the roadbed and rails with Tamiya red-brown is a good alternative particularly for track that has that red-brown coloring.

Edited March 21, 2022 by bill937ca