Vertical Clearance in HO-Scale

[bpickering]

Making some initial plans for a layout To Be Built Later (after the 3-year-old passes the randomly-destructive phase...).

The Plan tentatively has two helixes down to staging track underneath the layout, as well as a helix up to a short-line second level (working with space constraints here, so making the best I can with what space I have.) [8]

Two of these helixes (one end down, and up to the short-line) will be concealed within the typical mountain. OK, since I'm planning on Pacific NW Terrain, so there are a few of them out here. [:D] Late 50s/early 60s era, so rolling stock isn't too over-long or over-tall.

At the other end, I've got a reasonably long curve/straight section (almost 80") before I enter the area the helix will be under. At 2% grade, that gives about 1.6" vertical clearance- surely not enough. [:(]

What I'm trying to decide is between a couple of solutions. One, several, or all may eventually come into the plan:

• Steeper grade (I'm not planning on incredibly long trains- 8-10 cars), so might be acceptable w/o helpers on the helix.
  
• Raise the city- by how much, though? Was considering having it a waterfront, so wouldn't want to be too high above the Terminal, even though there will be a scenery divider between.
• Running the helix under backdrops/building shells will be used somewhat, but there's not a whole lot of space before the helix is to run under the relative front of the cityscape.

SO... Question is, how much vertical clearance will I need? I'll obviously measure the rolling-stock I've already got, but I'm wondering if there are any good Rules Of Thumb? Anyone else got suggestions on improving clearance beyond the three I already listed?

Brian Pickering

[cacole]

If you plan on running double-stack containers or some of the newer rolling stock such as auto-max, you'll need 4" of vertical clearance in HO scale.

[nfmisso]

Visit the NMRA site, and look up the Recommended Practices, and purchase a NMRA track guage.

[bpickering]

Already have the track gauge.

Will CERTAINLY look up the RP. I'm just getting back in for first time in 20 years, this time as a modeller, rather than a teen playing. I'll take any advice I get, from wherever.

4", huh? Hrm, that's going to take some doing.... Well, as I noted, I'm not planning on starting construction for some time, yet. Guess I'll follow another piece of advice I read, and construct a ramp to test climbing capabilities.

Double-stacks weren't too popular in the late 50s/early 60s, IIRC ([:D]), but since it will (hopefully) eventually be a father/son project, I shouldn't rule out Time Travel.

Anyone else wanna chime in with recommendations?

Brian Pickering

[dehusman]

3" Min
4" better
8" if you want access (is enough to lift a car over the top of a car on another track).

Dave H.

[cwclark]

Id say 3 1/2" minimum, 4" if you use ship container cars or auto racks...and to answer your question..the helix is going to have to be built into a bigger radius so that you can get the rise you need in comparison to the grade you will need...Chuck[:D]

[ndbprr]

Don't overlook the possibility of having the railroad go around the walls gaining elevation the entire way. That way your trains are always visible and the grade is minimized. It also gives you a longer run. perhaps one helix at the end would allow you to do it all over again or reverse loops would do teh same thing.

[Anonymous]

Hi Brian,

Sounds like I'm not the only one who wants a 3-decker layout to make the most of space! As for the 3 year old getting out ot the random destruction phase... you've heard the song..."You ain't seen nothin' yet". Believe it!!!!!!!!!

As for your issue. Yyour staging > city helix has a problem with the track coming from the terminal from what I gather. Might I suggest that you set your base elevation at the intersection of where the track passes comfortably over the helix? This helix I presume is the one gong to the staging level. If so, can you set the tracks leading to it at a downward grade? This would help "sink" the front edge of the helix in your city scene. The upper deck shortline helix can be easily adjusted to fit your needs. Adjusting the space between each of the layers - not necessarily having a uniform spacing may help.

Best wishes,
Dimitri Emelianoff

[Anonymous]

I'd second CW's 3.5"... also get cars that are the max height & length you'll use (length would be for radius)
Check rails under bridges and where grade changes... this can be a 'surprise' defect in RP's clearance standards! (And a rude surprise!) You can get the cars to 'bottom out' or strike the upper level if the trucks are at one level and the center of the car requires another. Sooo... make those transitions in grade gradual. but also, have the equipment ready to check your work.

[lrsr]

just a tip get it right the first time I didnt and had to daylight some tunnels and lower benchwork to accomodate the double stack that I just had to have. Right era but not long released for use. good luck and remember to have a FUN.Also the modelrailroader has run articles on train clearences comparison with the standard guage with some interesting results. so dont rely entirely on the guage.