Referencing my previous two posts: Backing/Shoving Long Trains (9-23-11), and Backing/Shoving Long Trains – Part 2 (12-26-11), I’m adding this thread Backing/Shoving Long Trains – Part 3 - FLOATING TRUCKS. I think you will find it at least interesting, and it will probably be my last article on this subject.
After considerable thought and experience on this subject, and along with proper railcar weight, proper railcar/truck interface, and decent (not perfect) track, I believe that Floating Trucks are the key to successful, almost derailment-free operations, including backing of long trains regardless of (up to a point) track curves’ radiuses. I know this is a bold statement. Here are my thoughts.
First, what is a “floating truck?” Please bear with me here. This term popped into my mind a few weeks ago as I was watching one of my HO long (70 car) trains slowly run forward through my yard ladder track. I don’t do much switching so I use the ladder as part of one of two possible routes on this track loop. This ladder, going from right to left, has six back-to-back 20+ year-old Model Power #4 NS track turnouts on it (the first two turnouts are set on the curved routes, the remaining four on the straight routes), and immediately at the end of this string of turnouts there is an Atlas 30 degree crossing diamond. And from right to left the track is going away from me (this is visually pleasing to me.)
While watching the train go through this section that day my eye was drawn to the lead truck of one of the cars, and the truck’s behavior brought the term “floating truck” to mind. Here’s why. Most of the 6 turnouts have been in-place for 18 years and some of the plastic frog areas are wearing down a little. Also, the connection between the point rail and closure rail on many of these turnouts is not the smoothest – even though I’ve addressed a lot of them with a small file. Also, Model Power turnouts, as far as I know, have never been known as “high quality” turnouts. I even noticed for the first time the other day that from my side view some of the turnouts are slightly humped in the middle! And the Atlas diamond causes some wobbles/bumps in more than half of the cars crossing it. Do cars derail through here? Almost never, but some of the cars do bump and wobble.
Back to “that truck” and “floating trucks”. As I watched it moving along it appeared to be “floating” - it was smoothly rising and falling irregularly side to side, and irregularly “sliding” back and forth according the dictates of the track conditions (for example, left front up, left rear to the right, right rear down, and all of this continually changing.) It did this generally all the way through, and the car itself was staying fairly stable (I don’t remember the car type, but it was high-sided like a boxcar or hopper.) Now do all my car bodies stay stable when their trucks are doing their “floating”? No.
This particular truck was just like 99% of my railcar trucks – one-piece plastic (NO truck springs), and I think it had plastic wheels (with metal axles) – 85% of my 300+ railcars have plastic wheels, the rest are metal. The one-piece plastic truck is important and I’ll get back to it in a minute - see #3 below.
How can and why should my (and your?) model railroad trucks “float” through irregular track just like the real railcars’ trucks? My answer is three-fold:
1. None of my trucks are ever snugly attached to the railcars’ underbody. They are all “loose” precisely so they can swivel in any combination of vertical or horizontal directions – just like the prototype. By “snugly attached” I mean it like I understand a certain model railroad association recommends, i.e. keep one truck snugged up to the car’s bolster so the railcar rides smoother and doesn’t wobble (and hence derail?) so much.
2. Keep all the railcars’ weights close to the same (on the low end of the scale – roughly 3 ounces or less per railcar) no matter what the car length is. The heavier the railcar the more the railcar pressures its trucks to restrain their freedom of horizontal and vertical movements, and then they are more prone to derail. This in turn forces the construction of “perfect” track work. [Am I against perfect track? NO. It’s b e a u t i f u l . On the other hand do I personally want to spend my time and money to get “perfect” track? No.]
3. You know, it’s my understanding that most of us use trucks that are not actually sprung (I personally don’t like them even though they look good). I think most of us use the rigid plastic trucks. I’m betting that 95%+ of these trucks, at least with experienced modelers, have truck side-frame concave journal holes that are at 60 degree angles, and the axles are metal (steel) with 60 degree points on the ends. Note: I believe the horizontal axle/journal interface angle is half of the 60 degree total, i.e. 30 degrees.
So I was thinking about this. Let’s visualize the following: Looking at a truck from the rear, moving away from you on “rough” track under its railcar, we see it bobing, weaving, sliding, rising, and falling – often all at the same time. What are the axles in the truck side-frame journals doing? If the truck is made properly there is some smooth side-play for the axles in the journal holes [if not make more “smooth room” with that little hand tool reamer], BUT these axles and holes are angled (UNLIKE the prototype) – THIS IS IMPORTANT. Let’s say the axle was in equilibrium in regards to its two side-frame journals, but then track conditions force the axle to move to the right inside the truck frame (before the truck itself moves to the side). What happens? The right wheel goes down and the left wheel goes up because of the truck/axle angle interface. Here’s the point of what I’m saying – first, the axle/truck/railcar DOES NOT DERAIL when this happens, and second (this was my EUREKA! moment
), THIS SIDEWAYS AND HENCE VERTICLE AXLE MOVMENT INSIDE ITS TRUCK JOURNALS MAKES THE TRUCK FUNCTION TO SOME EXTENT LIKE A SPRUNG TRUCK ON THE PROTOTYPE. Our model truck side frames don’t flex or yield, but the axles functionally do! I BELIEVE THIS IS ONE OF THE KEYS IN KEEPING MODEL RAILROAD TRUCKS FROM DERAILING.
Summary A: My practical, real-world experience has been following the above three numbered practices (in essence having floating trucks), and backing 65- to 70-car trains around right angle dog-bone loops with radiuses of 22”, 19” and 16” with no derailments, even when running backwards at 35 to 50mph on the MRC Tech 2 Railmaster 2400 power packs. I’ve also run the 69-car train (in the forward direction and with about 18 52’ cars in it) many times through a hidden 180 degree curve (it’s a shortcut to free up part of the normal route) with just one derailment; the curve’s radius is 12”. I’m saying all of this because the proof of the pudding is in the eating of it.
Summary B: In my experience keeping one or more trucks snug against its railcar and/or having railcars with too much weight and/or not having axle side-play in the truck journals greatly inhibits the trucks’ abilities to stay on the track.
Am I saying everybody should build 12” radius curves and operate on them? No. Am I saying that I’m some sort of a professor of ???? No, just a guy with many decades of model railroad experience that likes to experiment with his model railroad in this fashion, with the goal of being able to operate trains that almost never derail* when running forward or - for flexibility and amusement - backwards.
* I, like you, operate model trains for enjoyment and particularly visual pleasure, and even one derailment every ten times around a loop with a 15-car train is irritating/frustrating. But that’s not all. If you’re like me then you keep in mind the thought, “Will it derail over there again?” When I do this I can’t mentally rest in the enjoyment anymore, even if I have removed the guilty railcar from the train. But, believe it or not, now when I operate all 3 long trains simultaneously (usually for about an hour every day or two), and even with one, two or all three running backwards, at least once out of every three sessions I am so comfortable that I fall asleep in my “dispatcher’s chair” – a high-back, used office chair - for a 15 minute nap. When I wake up they are all still quietly trundling around their loops. (I know it sounds boring. But, for me it’s obviously very relaxing and restful.)
Lastly, since I’ve “gone to all this trouble” in becoming “derailment free” (but not totally) I wanted to share my experiences and thoughts with you in hopes that they are helpful or at least thought-provoking.
Any comments, experiences, thoughts or “you’re crazy”s are welcome.
Thank you for taking your time to read this.
DougC
After considerable thought and experience on this subject, and along with proper railcar weight, proper railcar/truck interface, and decent (not perfect) track, I believe that Floating Trucks are the key to successful, almost derailment-free operations, including backing of long trains regardless of (up to a point) track curves’ radiuses. I know this is a bold statement. Here are my thoughts.
First, what is a “floating truck?” Please bear with me here. This term popped into my mind a few weeks ago as I was watching one of my HO long (70 car) trains slowly run forward through my yard ladder track. I don’t do much switching so I use the ladder as part of one of two possible routes on this track loop. This ladder, going from right to left, has six back-to-back 20+ year-old Model Power #4 NS track turnouts on it (the first two turnouts are set on the curved routes, the remaining four on the straight routes), and immediately at the end of this string of turnouts there is an Atlas 30 degree crossing diamond. And from right to left the track is going away from me (this is visually pleasing to me.)
While watching the train go through this section that day my eye was drawn to the lead truck of one of the cars, and the truck’s behavior brought the term “floating truck” to mind. Here’s why. Most of the 6 turnouts have been in-place for 18 years and some of the plastic frog areas are wearing down a little. Also, the connection between the point rail and closure rail on many of these turnouts is not the smoothest – even though I’ve addressed a lot of them with a small file. Also, Model Power turnouts, as far as I know, have never been known as “high quality” turnouts. I even noticed for the first time the other day that from my side view some of the turnouts are slightly humped in the middle! And the Atlas diamond causes some wobbles/bumps in more than half of the cars crossing it. Do cars derail through here? Almost never, but some of the cars do bump and wobble.
Back to “that truck” and “floating trucks”. As I watched it moving along it appeared to be “floating” - it was smoothly rising and falling irregularly side to side, and irregularly “sliding” back and forth according the dictates of the track conditions (for example, left front up, left rear to the right, right rear down, and all of this continually changing.) It did this generally all the way through, and the car itself was staying fairly stable (I don’t remember the car type, but it was high-sided like a boxcar or hopper.) Now do all my car bodies stay stable when their trucks are doing their “floating”? No.
This particular truck was just like 99% of my railcar trucks – one-piece plastic (NO truck springs), and I think it had plastic wheels (with metal axles) – 85% of my 300+ railcars have plastic wheels, the rest are metal. The one-piece plastic truck is important and I’ll get back to it in a minute - see #3 below.
How can and why should my (and your?) model railroad trucks “float” through irregular track just like the real railcars’ trucks? My answer is three-fold:
1. None of my trucks are ever snugly attached to the railcars’ underbody. They are all “loose” precisely so they can swivel in any combination of vertical or horizontal directions – just like the prototype. By “snugly attached” I mean it like I understand a certain model railroad association recommends, i.e. keep one truck snugged up to the car’s bolster so the railcar rides smoother and doesn’t wobble (and hence derail?) so much.
2. Keep all the railcars’ weights close to the same (on the low end of the scale – roughly 3 ounces or less per railcar) no matter what the car length is. The heavier the railcar the more the railcar pressures its trucks to restrain their freedom of horizontal and vertical movements, and then they are more prone to derail. This in turn forces the construction of “perfect” track work. [Am I against perfect track? NO. It’s b e a u t i f u l . On the other hand do I personally want to spend my time and money to get “perfect” track? No.]
3. You know, it’s my understanding that most of us use trucks that are not actually sprung (I personally don’t like them even though they look good). I think most of us use the rigid plastic trucks. I’m betting that 95%+ of these trucks, at least with experienced modelers, have truck side-frame concave journal holes that are at 60 degree angles, and the axles are metal (steel) with 60 degree points on the ends. Note: I believe the horizontal axle/journal interface angle is half of the 60 degree total, i.e. 30 degrees.
So I was thinking about this. Let’s visualize the following: Looking at a truck from the rear, moving away from you on “rough” track under its railcar, we see it bobing, weaving, sliding, rising, and falling – often all at the same time. What are the axles in the truck side-frame journals doing? If the truck is made properly there is some smooth side-play for the axles in the journal holes [if not make more “smooth room” with that little hand tool reamer], BUT these axles and holes are angled (UNLIKE the prototype) – THIS IS IMPORTANT. Let’s say the axle was in equilibrium in regards to its two side-frame journals, but then track conditions force the axle to move to the right inside the truck frame (before the truck itself moves to the side). What happens? The right wheel goes down and the left wheel goes up because of the truck/axle angle interface. Here’s the point of what I’m saying – first, the axle/truck/railcar DOES NOT DERAIL when this happens, and second (this was my EUREKA! moment
), THIS SIDEWAYS AND HENCE VERTICLE AXLE MOVMENT INSIDE ITS TRUCK JOURNALS MAKES THE TRUCK FUNCTION TO SOME EXTENT LIKE A SPRUNG TRUCK ON THE PROTOTYPE. Our model truck side frames don’t flex or yield, but the axles functionally do! I BELIEVE THIS IS ONE OF THE KEYS IN KEEPING MODEL RAILROAD TRUCKS FROM DERAILING.Summary A: My practical, real-world experience has been following the above three numbered practices (in essence having floating trucks), and backing 65- to 70-car trains around right angle dog-bone loops with radiuses of 22”, 19” and 16” with no derailments, even when running backwards at 35 to 50mph on the MRC Tech 2 Railmaster 2400 power packs. I’ve also run the 69-car train (in the forward direction and with about 18 52’ cars in it) many times through a hidden 180 degree curve (it’s a shortcut to free up part of the normal route) with just one derailment; the curve’s radius is 12”. I’m saying all of this because the proof of the pudding is in the eating of it.
Summary B: In my experience keeping one or more trucks snug against its railcar and/or having railcars with too much weight and/or not having axle side-play in the truck journals greatly inhibits the trucks’ abilities to stay on the track.
Am I saying everybody should build 12” radius curves and operate on them? No. Am I saying that I’m some sort of a professor of ???? No, just a guy with many decades of model railroad experience that likes to experiment with his model railroad in this fashion, with the goal of being able to operate trains that almost never derail* when running forward or - for flexibility and amusement - backwards.
* I, like you, operate model trains for enjoyment and particularly visual pleasure, and even one derailment every ten times around a loop with a 15-car train is irritating/frustrating. But that’s not all. If you’re like me then you keep in mind the thought, “Will it derail over there again?” When I do this I can’t mentally rest in the enjoyment anymore, even if I have removed the guilty railcar from the train. But, believe it or not, now when I operate all 3 long trains simultaneously (usually for about an hour every day or two), and even with one, two or all three running backwards, at least once out of every three sessions I am so comfortable that I fall asleep in my “dispatcher’s chair” – a high-back, used office chair - for a 15 minute nap. When I wake up they are all still quietly trundling around their loops. (I know it sounds boring. But, for me it’s obviously very relaxing and restful.)
Lastly, since I’ve “gone to all this trouble” in becoming “derailment free” (but not totally) I wanted to share my experiences and thoughts with you in hopes that they are helpful or at least thought-provoking.
Any comments, experiences, thoughts or “you’re crazy”s are welcome.
Thank you for taking your time to read this.
DougC
