I'm sure they had to do with moving either coal or ash.

Yes that is an air compressor, and it would have been in my truck after the picture was taken :D

I'm with Gratefulzens, another condenser. Scooter... how on earth did you come up with that conclusion?

Autoguy, doubt it. They're quite easy to repair actually, especially with the outside plate taken off like that. This would have been a routine overhaul in a plant like this. In fact, I'm sure this isn't the first time that was taken apart considering how many years of operation this plant saw. During the winter when electric demands were low, if a plant had more than one unit, they would take one out of service to do routine maintenance on it, as well as major overhauls. It looks like they were well into an overhaul here when the plant was shut down.

Another thing to think of -- Most plants were built with more than one unit. As time goes on and we discover new technologies to make plants run more efficiently, they might have built 1 or 2 more units and taken the older ones out of commission. So even though the plant was still operational, the older units may not have run for years even before the plant was closed. In that time, parts from the older units may have been scavenged to do repairs on newer units, or repairs at other plants even.

I have to disagree with kevlar. This looks like some sort of condenser or heat exchanger. Cool water (usually river or sea water) would be pumped through those thousands of tubes (they look like holes, but they are actually tubes probably 20' long with another waterbox on the other side like the one you're looking at.) at an astounding rate, probably approaching 1000 gallons a second, while the steam would flow around the tubes and condense back into water. Normally there would be a giant plate on the end with a bunch of hatches in it. (seen in one of the other pictures.) On a regular basis, the condenser would be taken out of service, and workers would climb through the hatches to clean the tubes. They'd be loaded with thousands of little brushes and shot through with high pressure air and water. The reason the whole cover would be taken off is for tube replacements. If one of those tubes carrying sea water leaked and let salt water or debris into the turbine, it could be destroyed.

For everyone asking where the tubes are, that whole inside wall you see with all the holes in it, well all those holes are tubes about 1" in diameter. The big poles sticking out are what the cover would be bolted onto. (notice they are flush with the outside edge.)