Track curve question

[traindaddy1]

I have a lot of traditional 27" diameter O27 Lionel tubular track. 

 I was wondering how to use what I have to lay out some configuration that would accommodate rolling stock that requires larger minimum curves.  Example: One piece curve, followed by a piece of straight, then a piece of curve etc.

Question: Would this idea work and if so, how large a minimum curve requirement do you think could be achieved?

I KNOW, I KNOW, The first thing you will say is: "Why don't you just get some O-42" or  O-54" diameter curved track, you're using up the space anyway and besides, it will probably look ugly".

Answer: If I can use what I have, I can put the new track money into something else.

As always, many thanks.

 

[marxalot]

The minimum radius is how equipment is usually rated. You could have 44 straight pieces of track and then a piece of 027. The minimum radius encountered is still 027. Now maybe some rolling stock would appreciate this interspersing of 027 radii but I don't think it will accomplish what you want.

 

Jim

 

[FJ and G]

2 items.

1. your best bet is to simply layout out some track and try it. Larger rolling stock will generally negotiate 027 but will look funny and might cause derailments down the road.

2. To save money, remove the ties and bend the rails to whatever diameter you wish. I've done that. Note, however, that you will need to connect your rails in different places, vice all 3 at the ends of each segment, as bending the rails will mean you no longer have the same sectionals (just treat each rail as a sectional; there won't be any problems using this method).

THese outside rails are bent 027.

[lionelsoni]

The chord of an O27 curve is 9.567 inches, which is roughly the spacing between trucks of most rolling stock.  So, a car or locomotive stretched along that chord will have its trucks turned to pretty much the same angles whether the curve is one isolated 45-degree section or part of a larger curve.

However, if you were to cut 45-degree sections in half, the truck angles of a car or locomotive straddling that shorter piece would be cut about in half, to very near the angles that you would see on an O54 curve.  If you are willing to cut them and alternate with straight sections (or straight half-sections), I think this has a good chance of doing what you want.

[traindaddy1]

JIM---FJ and G---Bob:  Thanks for your input.  Now that I really think about it, I'll probably stay simple and go with the O-42" track. Thanks again.

[dbaker48]

Bob,

You confirmed with math what I was thinking would probably work.  THANKS !!!!

[otftch]

Why don"t you use the 027 curves on sidings and short line areas.Almost everything will work on the curves. The biggest problem is the turnouts.You would have to use them with the straight path on the mainline because the switch machines are in the way.Most sidings in real life are much sharper than mainline track. This approach has worked well for me.

                                                                            Ed

[waltrapp]

I use 27" curves.  What I have seen is that trucks are retricted from rotating far enough by side ladders and such and this causes the derailment.  I would think that ANY LENGTH 27" curve that was at least as long as one truck could be a potential problem.  If the truck doesn't swing that far, then it doesn't swing that far, right?  A 3" piece might be long enough to cause the derailment.

Remember the original problem with BEEPs not handling 27" curves?  the coupler hole in front wasn't large enough to allow the truck to swing far enough.

In my opinion if the truck has room to rotate then it would seem logical that no matter how long the piece of rolling stock is, or how long the curve it, it will work.  May look funny, but it should stay on the rail.

Just offering my opinion, not saying it's right, but I wouldn't offer it if I thought it wasn't :-) !

- walt

 

[traindaddy1]

Ed--Don--Walt:    Thanks again.

[waltrapp]

traindaddy: I meant to cite and example but forgot: I bought a K-Line PRR caboose - maybe 8" or so long, right?  Well, I had to return it - it couldn't handle 27" curves!

The point is - you can't just go by the length of the piece.

- walt

[lionelsoni]

If the two trucks are on the same circular O27 curve, the angle that each truck will make with the body is the arc-sine of half the quotient of the spacing between trucks and 25 inches (the diameter of the curve).  If the curve is between the two trucks, the average angle that each truck will make with the body is the amount of direction change in the curve.  By using short pieces of curved track alternating with straight sections, you can reduce that truck angle to be as small as your rolling stock needs.

[waltrapp]

Bob,

I have to admit that I can't absorb what you just said, but let me relate my experience with the K-Line caboose.

I had the caboose going down a straight track entering a 27" curve.  DERAIL.  Why, because the front truck couldn't rotate far enough to enter the curve.  Maybe this supports your theory I don't know, but it's my experience.

- walt

[lionelsoni]

Walt, I wouldn't dispute that your caboose derailed.  But I'm pretty sure that it had to travel some small distance into the curve before it did.  If the curved section had ended just before the point where the caboose derailed, the truck would not have rotated any farther and the caboose would have made it through the curve.  For that car, with its apparently very short distance between center bearings, the O27 curve fragments would have to be very short to be of any use in getting the effect of a longer radius, perhaps just a few inches.

[phillyreading]

If you were to use Lionel or K-Line half curves in 027 with a half straigth in between it may work better. When a manufacturer says to use 054 or larger usually you must use that size especially on locomotives.

Lee F.

[traindaddy1]

First of all, thanks Lee F.

BOB -- WALT:   I've got to say that I never expected such a dialog.  This "older" guy  really has no technical expertise and appreciates your 'friendly' exchanges as I always like learning new stuff.

Mainly, I "play" with my Lionel and only think up questions while I am waiting at the station for the next train.  (You guys certainly have more knowledge and I think it is great)

Until my next question, thank you for your input.

[lionelsoni]

Well, you asked a particularly interesting question.  So thanks for the opportunity to entertain ourselves by speculating about the answer, whether or not the result is useful!

[fjerome]

"One piece curve, followed by a piece of straight, then a piece of curve etc."

i can guarantee you that you would not like the way the train would look traversing this section.

[traindaddy1]

fjerome:  You're probably right. Thanks.

[waltrapp]

traindaddy: you're comment "fjerome:  You're probably right. Thanks".  He's DEFINITELY right in my opinion!  I tried something like that one year and the train kind of 'jerks' it's way thru the curve, if you can picture that.  Steamers look worse than diesels going thru that configuration.

Again, just MY opinion, but one based on fact this time!

- walt

[traindaddy1]

Walt: Your "opinion" always counts. Thanks.