What is this?

[rem37411]

I was traveling downtown Chattanooga yesterday and saw this machine. Anyone know what it is? Sorry for the fuzzy pic. Quickshot with my blackberry.

 

[Wojo]

Off hand It appears to be a torsion beam tamper, used to maintain "surface".
In layman's terms maintain a level trackbed by use of an onboard computer.

 

[Rico]

That's called a tamper.
Some use a laser light to align the rails then they grabs the ties and lift and shift them to the proper height and alignment. Vibrating spades then push and pack ballast beneath them.
All you have to do is push a foot pedal and the machine automatically moves to the next two ties.
Doing curves is somewhat of an artform involving graphs and calculations.
Newer models, Continous Action Tampers, do all this without stopping by sliding the whole tamper mechanism ahead on rails to the next ties while the machine crawls merrily along.

There should have been a "broom" or ballast regulator not far behind this machine.

 

[rem37411]

OK! That makes sense now, just looking at it I had no idea, I thought it was some kind of cleaner but thought that didn't make sense. I didn't see anything behind it as this is kind of a siding that is not really used anymore. But thanks for the answer! Awesome...I love learning something everyday! One of you guys who works on a rail should start a "Daily bit of knowledge" thread!