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Discussion Starter · #1 ·
The snow has finally left the GCHRR right of way and spring maintenance is underway. Not all of the frost is out of the ground yet, however, I thought it might be instructive to see what may have settled more than acceptable, so, TA-DA!, the Greensville-Crooks Hollow Grade Measurement Train headed out on the rails to look for dipsy doodles...
A laser level, coupled to a pair of flat cars, pair of locos for low speed steadiness, and a cleaner car makes up the consist:

As it turns out, the level, inverted, places the beam right on the seam in the middle of the flatcar upright. In the sequence that follows you can see the dot move according to the change in grade. In the last photo, you can see that the track has risen quite a bit over a short distance (dot dropping). I run track power, and this is an area where the locos are sometimes flaky, especially if the track is dirty. I now see that the grade changes may be enough to affect power pickup.
I found an area thats a veritable roller coaster even though it wasn't that evident. When laying track I use a small bubble level that straddles the rails as I set it up. This method has pointed out areas the bubble didn't really identify. Trains working to play trains! Doesn't get any better!


 

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Discussion Starter · #4 ·
Posted By Duncan on 04/06/2008 12:52 PM
Cool concept for a visual reference!!
Now, if you mounted "two" of them, one near each outboard edge, that would give you a pretty quick gauge of side to side roll...
Not criticizing, just thinking a little differently...

My bubble level (a typical round carpenter's bubble level mounted on a piece of lucite about 2 1/2" long) centered on a flat car does that pretty well. You need a flat car that doesn't rock side to side too easily. I find just laying the bubble level across the track shows me pretty quickly the lateral slope.

If the train is moving at a pace you can see the laser dot bob and weave all over. By angling the level you can accommodate some curves (I could do 16' curves easily - 8' were a bit more difficult, but not impossible).
 

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Discussion Starter · #6 ·
Posted By Torby on 04/07/2008 7:27 AM
Your level keeps the beam level as it moves? Otherwise it would show you changes in grade, not grade itself. (The derivative of the grade.)




You are correct, it's reflecting the delta, not the absolute grade slope. Its certainly possible to add an accurate scale to the bulkhead and calculate the real grade, especially if you add many more flat cars between the laser and the bulkhead, but that wasn't the point of it. Grade measurements can be made quickly and easily with the laser alone.

"Grade measurement train" is probably a misnomer; "grade delta measurement train" would be more accurate.
 

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Discussion Starter · #9 ·
If the track does a dip and a twist the dot describes a circle :)" border=0> It will also show you a) an out of gauge pilot, or b) track not laid straight as the dot swings back and forth... One area of my track that surprised me was a section of 16ft curve that over a span of about 7 feet looked like a roller coaster dipping and rising significantly in 3 places. You had the sense watching the train go over it that things weren't quite right, but the laser pointed out exactly what and where the problem was.
Hmm... Before, I was just running trains blissfully ignorant that the track was not PERFECT..... However, watching my new steam Mogul launch itself twice off two sections of slightly elevated track has encouraged me sort out the track issues...

I guess now I'm going to have mount the video camera in a gondola behind the laser to get it all on tape for youtube! lol!
 
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