I've done searching on the forums and would like to use one number for a center to center spacing and stick with it.
Thanks
Matt
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quote:You can't go wrong adhering to those standars.
quote:Class Ia
Includes the largest steam locomotives with four-wheel trailing trucks, articulated locomotives, those with rigid wheelbases in excess of 20 feet, full length passenger cars and other long rolling stock.
quote:Construction or operation of equipment on curves sharper than those listed for its class are neither prohibited nor recommended.
quote:Is there a number that others have settled on or how about I don't have any tracks that are closer than _________ " rail centers?
quote:I can verify Dr. Hikel's comments.
The Alas track system maintains a 4.5-inch center rail-to-center rail distance "everywhere".
Jan
I hope this note helps in this discussion.
As some have mentioned above articulated locomotives and long passenger cars are the problems when dealing with curves. Standard distances between tracks are not the rule here. In three areas on my layout I have three track running toghther in a 72 in. curve.
When laying the track I got out the AC-9 and some 21 in. passenger cars and ran them back and forth in the curved area on adjacent track. For these items to pass track center rails vary in distance from 5.5 to 7.2 inches.
On most of the straight of ways I can get the center rails to be about 4.5 inches.
I hope this information is of some value. Using the offending locomotives and passenger cars by testing when laying track will keep you out of trouble later!
Mike
Two switches set up for a crossover will also drive track centers.
If you're using flex track, you can vary the spacing to suit your needs. On tangent (straight) track, you can run the track as close as 13 feet (3.25 inches) and spread the tracks apart going into curves. You can use a larger easement to go into a 36" radius (O-72) curve on the inside and a smaller easement to go into a 42" radius (O-84) curve on the outside. That gives you safe spacing on the curves while maintaining closer spacing for straight track. The other alternative is to make curves so broad that the distance in-between doesn't matter much. We have a stretch on the layout that has 4.5" spacing, but even the biggest articulated locomotives keep their boilers over the track. The curve in the foreground is the sharpest in this stretch at about 96" radius (O-192) and the lead-in curve at the far end (extreme left) is so broad we couldn't estimate it accurately.
Here's a shot from the other end. The track on the other side of the bridge is at 48" radius (O-96) for the inside curve and 53" radius (O-106) on the outside, being spread apart via easements. We've had full scale equipment running through that curve for years and nothing has ever hit.
I went through all this last year. If you want to be able to run anything out there use 6 inch minimum.
A new Layout Planning and Construction section with
Track Clearances for Curves Tunnels, and Pantograph Skids
Accessory Footprints - Postwar and Modern
has been added to my website.
Correct me if i'm wrong but, I think the diameter of the curves would dictate the spacing, for example: you would require less spacing with O-90 and O-81 curves than with O-72 and O-54 curves.
Here's what 4" track spacing looks like when a 3rd Rail Allegheny passes on the inside of an 18" coach on the outside. The results are not pretty. I thought that since Ross track came in 4" radii increments that was the "correct" spacing. I was wrong! When i redesigned the layout I upped it 5" minimum, but basically keep them much further apart and on different levels whenever possible. I didn't want anything hitting anything else anytime, any where.
While 4" looks prototypical, it's operationally difficult with scale-length long equipment.
Every manufacturers track style presents different problems.
I use MTH RealTrax. My curves are O-72 and O-54 exclusively. This represents a 9 inch spacing everywhere between the outer track and the inner track. This spacing allows me to run very long passenger cars and 89 foot flatcars without problems with overhang on curves. I use O-72 crossovers between an outer O-72 track and an inner O-54 track. I also have an O-72 wye track entering my switchyard.
We are using 072 and 080 curves for the mainlines, and went with a 6" center to center spacing. Granted that is not required on straight track, but we have a lot of winding curves, several articulated engines, and a few full length (21") passenger cars. Clearance is NOT an issue with the 6" centers, for any of our equipment. We went with a 4" track center from any wall or bench work bracing with no issues. Everything was measured and designed for the BigBoy and 21" passenger cars....just in case
Looking at Lionel FasTrack, it's 6" centers due to the curves they have, and the new modules they sell kits for. I've been planning a layout for my house I just got, and due to size limits, I'm using O-36 and O-48 for my curves with O-36 switches. The switched put out to out also give 6: centers, but I can't speak for the larger radius switches. To make sure I wouldn't have any issues with my Big Boy or my son's Amtrak HHP-8 train set, I put an O-36 curve on paper and rolled the Big Boy and Amtrak coach with a pencil on the corner that hung over the most on the inside and outside. I measured and added it to a CAD model I had of the track (I'm a mechanical engineer so I planned my layout in SolidWorks during lunch hours.), and they cleared, just barely, but they did.
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