Most guys would go up and down the tight twisty stairs.
Not me, we find one of these handholes for pulling cables and drop right down.
Of course, I move my big feet first...
The view down the 25 foot shaft.
We set the prism up and plumb with a WILD NL (in the orange box on the left) and we drop steel tape for an HI.
All while rush hour zooms past.
Do the same a couple hundred feet up the subway platform and in about two hours or so we have transfered a base line where we can use it for trackwork.
If I recall correctly, you posted a few years ago about traversing down a stairway where you set points down on a landing, then resectioned in from below. I thought that was a clever solution. This is so much more accurate, with your equipment and techniques.
I looked up the spec on that NL. It's a pretty nice piece of equipment. I don't usually have the need for something like that in my arsenal, but if it ever comes up I'm getting one.
The wonders of technology: I'm reading this and posting from a subway car using the wifi at the National Zoo station
Notice the characteristic hunch of the smartphone walker in the background.
:gammon:
national zoo
Last spring at the National Zoo we saw the new "surveyorus lostus" exhibit
I heard it got more interesting at feeding time.