How high the tracks and roadbed are usually for a real railroad? Anyone know?
Depends on a lot of things. What is your situation?
I look out my window and I see raodbed at 0 where it crosses the street. I look on both sides of the road and it is about 8" for as far as I can see.
Certain heavy-duty eastern roads used to brag about their five feet of crushed limestone ballast. Add a couple of feet to the bottom of the drainage ditches along the subroadbed and you’re up to a full-scale inch in HO. On the other hand, there are some roads that were originally laid on the ground and were never prosperous enough to add much ballast.
If by track height you mean height of rail, the sections commonly available scale out as follows in HO:
Code 55 - 75 pound (per yard)
Code 70 - 100 pound
Code 80 - 127 pound
Code 83 - 133 pound
Code 100 - overscale for 155 pound, which should be code 92.
Granted that code 55 and code 80 are usually found in N-scale flex track, there’s no law that says they can’t be used for other scales if relaid on appropriate ties.
On back tracks and sidings, infrequently used lines, they would sometimes be close to ground level, but I have seen them well built up, a foot or more off the surrounding terrain. Depends on local rainfall and drainage.
Mains are that much better maintained, but in central BC the CP main is only a foot or so above the surrounding terrain. On banks, it may be two or three feet above the downhill side.
Road beds were graded to try to give as level a run as possible. Since the surrounding terrain is usually not flat, the height of the roadbed is going to vary greatly. It might only be a foot or two high or it could be on a 20 foot embankment.
Cork and foam roadbed material is approximately 1 scale foot high which is probably the minimum height you would want for mainline roadbed.