Wall Clearance

3.75 inches depending on curve degree.

0-72 Minimum is what I am planning.

For just a little comfort and I MEAN LITTLE stick with 3.75, I would not go any closer for sure. General rule of thumb is 4.5 on most layout software.

My VL-BB has a bit more than a 3" overhang on O72 curves.

@CurtisH what layout design software are you using?  I've used RR-Track and SCARM, neither one seemed to have a default, preset, or any kind of facility for setting the curves a minimum distance from the wall (or layout edge.)  And it would be more convenient if they did!  What am I missing??

Obviously the answer to the original poster's question depends on the equipment, and the size of curve you're using. 

I've been wondering about a 773 Hudson on Atlas O36 myself.  I know the cab roof overhangs quite a bit, especially when running in reverse.  Problem is, all my stuff is boxed up and buried so I can't make an empirical measurement.

Ted S posted:

@CurtisH what layout design software are you using?  I've used RR-Track and SCARM, neither one seemed to have a default, preset, or any kind of facility for setting the curves a minimum distance from the wall (or layout edge.)  And it would be more convenient if they did!  What am I missing??

Obviously the answer to the original poster's question depends on the equipment, and the size of curve you're using. 

I've been wondering about a 773 Hudson on Atlas O36 myself.  I know the cab roof overhangs quite a bit, especially when running in reverse.  Problem is, all my stuff is boxed up and buried so I can't make an empirical measurement.

Somewhere I picked up a 4.5 inch clearance when I was doing my track plan (no Software was used as I did it freehand on graph paper which I DO NOT recommend). I remember calling MTH for the big boy clearance which was 3.? ( I think 25 but can not remember). I did NOT have proper clearances along walls as I laid Atlas 21st Century O track by putting a 4' level on it's side and sliding to wall then putting track tight to it. Simply pulled the level out and straight track. Only later did I find that some of my trains hit the wall coming off the turns on the end. That is when I called to get the measurement of overhang of a big boy. Also found the 4.5 measurement but can not remember where although I think it was Atlas Software in the documentation. At my age I wear my name on my shirt to remember who I am not to look like a uniform, so I definitely have trouble remembering back to 2014. LOL

O54 outer loop, O45 inner loop.   There is a limit. 

O54 curves  Atlas Dash 8. 

O45 curves  same Dash 8 set.  Tracks are 4.5" Center to Center. 

This Weaver C630 has an unusual 3 axle truck with a set of blind drives on the inside axle.  On O45 you can see the wheel beyond the track.  

Ted S posted:

I've been wondering about a 773 Hudson on Atlas O36 myself.  I know the cab roof overhangs quite a bit, especially when running in reverse.  Problem is, all my stuff is boxed up and buried so I can't make an empirical measurement.

O-36 is my minimum mainline curve. I have 2.75" on the outside of the curve, and 2.5" on the inside. That lets me run the scale hudsons, 15-inch aluminum cars, and anything else Lionel made, up to about 1990. I have not tested Lionel's scale engines from the early '90s - the 2-8-2s, 4-8-2s, and 4-8-4s (tho, of these, only the 2-8-2s are rated for O-31 anyway).

I placed my O72 track 6" from center line of the track to the wall so that I knew my BB would not hit.  This also allows you a tiny bit of room to add some details against the wall without being taken out by the BB.

bbenakjr posted:

What's the closest I can get the track to the wall without my Big Boy and other long passenger cars not hitting the wall on the curves?

Thanks, Buddy

 

Overhangs vary by scale and manufacturer.  On some engines, the largest overhang is the roof of the cab when in a curve.  John