Why do day do dat? - Understanding grades

[tstage]

Here's probably a very basic question for you all about track grades:

Let's say you're driving along in your car and you glance over and see three tracks running parallel to one another. Now you notice that the track closest to you is actually graded lower than the other two tracks.

Would it be safe to assume that the lower track is probably a spur and/or a siding of some kind? Why are there different grade heights to track?

Thanks for your answers in advance...

Tom

[ndbprr]

Either that or a different railroad.

[pcarrell]

I saw once where they built the new tracks beside the old ones and that made a height difference.

[dehusman]

The outside tracks will be slightly lower for drainage, if they ware significantly different (over the thickness of a tie) then its probably a secondary track (track other than a main track).

The secondary tracks are lower to minimize the cost of ballast (you don't need as much for a slower speed, lower capacity track), for drainage (outside lower allows water to flow away from the main track) and it tends to keep cars from rolling out onto the main track (assuming the side track is level itself.)

Dave H.

[tstage]

Dave,

I was wondering if drainage might be the case. The middle track is definitely a high track. I'm pretty sure that at least two of the three are main tracks. But it's sorta difficult to see if the other outside track is lower, as well. They belong to CSX. (Amtrak uses that route on it's way to Chicago once a day.) I drove back by last night and deduced that the two inside (main) tracks are at the same height. The track closest to the road is probably 2 - 3' lower in height.

That also makes sense about the lower track keeping cars from rolling out onto the main. I hadn't thought of that. Thanks, Dave! [:)]

Tom