Minimum Track Height

This question boils down to whether or not grade will be an issue.  If grade is not an issue, don't worry about minimum height and just give yourself tons of room.  If grade will be a consideration, then you really have to measure the specific tallest equipment you intend to run and make that your minimum.

@Long Hair posted:

This question boils down to whether or not grade will be an issue.  If grade is not an issue, don't worry about minimum height and just give yourself tons of room.  If grade will be a consideration, then you really have to measure the specific tallest equipment you intend to run and make that your minimum.

My plan is to have a double-track mainline that will cross-over itself, so there will be a grade.  With that said, currently, probably my tallest piece of rolling stock is an MTH auto carrier, but I would like to plan for the future if I decide to one day purchase a double-stack container car.

A tunnel portal would take 7 1/2" (minimum level difference).   There have been threads about the grade to achieve 7 1/2" elevation difference.  If you can accept 3% to 5% grade, 12ft to 15 ft of run is required.  More than 15 ft lowers the grade. 

keep your grade at 2 percent .

@Dave Koehler posted:

keep your grade at 2 percent .

That would need a run of about 24, 25 feet, somebody can do the math for the exact number. How many of us really have that much room?  Just telling everybody to keep at 2% is not really helpful without knowing the space they have. A helix may work if he has the room for a 6 ft diameter circle of track.

This tunnel portal  is a MTH railking model and the autorack is MTH scale.

The portal had to be raised to clear the autorack car, at the time my tallest rail car.  The bottom of the portal is about the top of the rails. The portal is too low the run a MTH double stack car with the top container.

I used the autorack car and a homemade 99ft work train car to check right of way clearance.   

I wished now that I would have had a MTH double stack car/ Lionel 86ft autorack or 86ft boxcar to check right of way clearance.

My track runs between the upper and lower layout are approx. 25 feet long.

The change in track elevation starts at the grain elevator on the left and ends about 1/3 of the way on the far wall.

My layout is 45'x24' and is a point to point (end to end) with reverse loops at each end of the runs and has 3 levels. Because of the length, I was able to plan long runs with grades less than 1%.  Even with Premier engines, you want as little grade as possible. Previous to this layout (now going on 32 years old) I had two others in the same space and did not plan all of this out. I ran into problems with height. So I was very careful on this one to make a drawing with radius's and grades and tunnels clearances Etc. I don't think you can plan too much on these issues. I run a double track main with 3 tracks in some spots. Even with that  amount of planning, I still  had  some minor issues.  For starters, most engines are about 4 " and most cars similar. So on top of your base plywood or whatever, you need to add  your road bed height ( I used homasote at 1/2") , then the track height and then you can add what you want for clearances. Finally, you need to look at your side overhangs. When I purchased an MTH Santa FE type 2-10-4, it wouldn;t go through some on my landscaped curves. I had to shave spots but finally got it. But good planning will help you minimize your problems once you start operating.  Good Luck. You are doing the right thing. Bill