A question (probably a loaded one): what is the recommended clearance inside of a curve if I plan to (possibly) have passenger cars/auto racks/etc.? I have tried to open up the clearance in the curves compared to the straightaways, but I don’t know what’s appropriate, and don’t own a long car like that at the moment.
That is going to depend on several things - 1.) the radius of the curve. 2.) the length of the cars. 3.) how far in from car ends the trucks are.
Outside of curve the main overhang is going to be the car ends.
Inside of curve the overhang issue will be at car center.
Thing to do without having that size car is take something flat and stiff enough to attach trucks to and make a mockup of car floor. Then lay out track, or alt least mark curve radius on floor.
Then place car, or mockup, on track, or drawing of track, and mark overhang at car center on inside of curve and at car ends on outside of curve.
You will notice the amount of overhang changes with curve radius and during entry to and exit from curve.
Auto racks are something like 85 to 87 feet long, so I’d make a mockup 90 feet long just to be safe. And we’ll round up to 11 feet width.
Let’s see, 90ft x 12 inch/ft = 1080 inches.
1080/29 for 1/29 scale = 37 inches long.
Width comes out to something a hair over 4.5 inches; for figuring required clearances I’d round car up to 5 inches wide for a good safety margin.
Oh! playing in Google found this with handy diagram, http://www.thortrains.net/betterg1.htm
"Of Cars and Curves
Your available space and scenery affect your track choices. What of clearance? Cars are wider than track, and without proper planning, could collide with scenery and other obstacles. Folks new to the hobby think car clearance is a matter of the height and width of the car. There is also the problem of “sweeping,” as I call it. On curves, the corners of cars swing outward, while the inside between the wheels overhang."
Good idea. Using those dimensions on paper on a 4’ radius curve puts the inside center of the car at 4.5" from the centerline of the track, or 3.75" from the inside ends of the ties.
Eric Reuter said:
A question (probably a loaded one): what is the recommended clearance inside of a curve if I plan to (possibly) have passenger cars/auto racks/etc.? I have tried to open up the clearance in the curves compared to the straightaways, but I don’t know what’s appropriate, and don’t own a long car like that at the moment.
I have a bridge that comes off the end of a 10’ diameter curve. I measured from the center of the track to the inside upright of the bridge pier and it’s about 3.5". When I run my 35" long custom Amtrak cars they do come very close but still clear it.
As to long cars, here is an example USA Trains Intermodal Car, Lowered and fitted with body mount Kadee centerset couplers that can be made to operate OK on 10 foot diameter track - and down to 8 foot dia. with some wheel drag.
Note the belly overhang on 10 foot diameter track shown below - where a turnout control may get in the way.
Another example long car is the USA Trains streamliner passenger car, also lowered and fitted with body mounted Kadee centerset couplers.
-Ted
Oh, Ted’s post raises an issue - at what curve radius/truck pivot angle will the backs of wheels collide with frame parts and coupler mounts?
The longer the car is the more critical the truck pivot angle becomes. I take this into account when body mounting couplers, striving for operation down to 8 foot diameter track whenever I can. Many times the coupler box can be modified (notched) for more wheel clearance, particularly when using the Kadee 906 box with its larger foot print.
-Ted
As I’ve been converting my rolling stock to 906s, I’ve been testing them on a section of 8’ diameter curve. But I don’t have anything longer than a 50’ box car at this point. This is all helpful. Thanks.
Eric Reuter said:
As I’ve been converting my rolling stock to 906s, I’ve been testing them on a section of 8’ diameter curve. But I don’t have anything longer than a 50’ box car at this point. This is all helpful. Thanks.
The “prototype railroads” and even trolley systems always had to deal with this same problem. It can be a great source of fun/frustration and even special orders for individual pieces of rolling stock.
Pulling instead of pushing can sometimes resolve the problem. This may require the addition of another run around to get the power on the opposite end.
Extended draw bars or couplers.
Extreme slow orders.
More weight.
Great ops potentials. Enjoy the ride.
One good “clearance” car I have is the Aristo RDC… the trucks are are the extreme ends of the loco, and it is long, lots of overhang in the middle and outside the curves. The scratched paint on the nose of mine prove they are doing their job ha ha!
Greg
Greg Elmassian said:
The scratched paint on the nose of mine prove they are doing their job ha ha!
Now all you need is the roof dent this C&O car picked up while previously owned by M&StL (https://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-laughing.gif)
http://byrnefamilyreunion.org/images/Marbone-Jct-WEB.gif
Lots of RDC photos here