elevation height

[greatn]

I suppost this would be just another newbe question but here goes.......
When you are constructing a layout from a drawing and the elevation show thing like 1" or 2" does this mean 1" from the plywood top or the from the top the the rails? My 4X8 goes from 0" to 71/2" on the drawing however now that the construction is finished, the rail height is 8&1/4" from plywood top to rail top.

[Anonymous]

I believe the height is above whatever serves as the 0" level, which is usually the plywood/base roadbed top. That's why you usually add a 1/2" or so to the heights of tracks that pass over other tracks (in HO) to give enough clearance when the track and roadbed is in place.

[Anonymous]

It's all relative, it doesn't matter where you measure from as long as it is always the same. So the difference in height from the lowest rail to the highest rail in your case should be 7.5". Does that make sense?

We were posting at the same time, I disagree a little, in most layout drawings I'd say that we are only talking about track, the top of the road bed is the relevant height. All heights are relative to track position.

[selector]

Jeff is correct. The whole idea is to run rolling stock and locos, whichever is the heighest in any one piece that you will have..or that a guest might bring. So elevations are relative to the tracks, unless specified in the plan that it is in reference to a given topography. Clearances, for example, all relate to what will pass under them mobile; not from tunnel portal top, say, to the sub-roadbed, but from rail-top to the apex of the portal, and anything beyond it. Same for overpasses, gantries, etc.

[greatn]

Hey thanks guys!! That is what I figured but I wanted to double check.

[Anonymous]

Yea, thanks! Guess I thought wrong about the elevation thing all these years, too. [B)]