I'm scratching my head (since I'm just a dumb construction worker ;) and figured maybe someone here could come up with a brilliant idea that I'm overlooking.

Background:
We have a large skidding system; essentially it's two heavy steel beams fully reinforced with two inverted channels (picture a cap channel not welded to the beam) on which the item we need to move (typically heavy transformers but whatever our customer wants) sits. Two large hydraulic cylinders pinned to the beam push the channels along the top of the beam, the pins are then removed, cylinders retracted, pins reinserted further along the beam, and then the cylinders re-extended in this fashion over and over to crawl the load forward. It's a fairly common piece of equipment in our line of work. The channels put about 100-140psi onto the beam at full load, but a more common operating range is about 50-70psi given that most of the cargo isn't at the systems maximum weight.

Traditionally we used to use a paste made of ivory soap flakes to lubricate it during use (economically, it was cheap, environmentally, it washed away and the volume we used wasn't a concern at a given site). The problem with flakes was two fold, primarily Ivory stopped selling them in 1993 and other brands just didn't work as well, and secondly, the paste is hard to work with when it's below freezing, which is quite common for our work here in Wisconsin. We were using grease afterwards but as you can imagine, that makes a huge mess since the surfaces are exposed (80' or so, 12" wide, right in the middle of construction sites) so they not only collect all sorts of dust and dirt but also get all over the workers.

We worked with a plastic engineer to design some low friction lubricant impregnated polymer plates to install on the skidding surface to use instead of the soap flakes and grease. In testing they work just fine. The problem we have right now in the short term is the beams have been cleaned and prepped for the plastic install (fastener holes drilled/tapped/etc, repainted), but some emergency jobs came up that we need to use the system on before I can get the rest of the project finished to the point where we can utilize the new plastic wear plates. So in the interim I need some lubrication options better than what we have.

So to summarize all the above:
Is there a good lubricating option for this situation that anyone can think of that is:
A) Economical (~$10-20/gallon)
B) Environmentally friendly/less messy than grease (water soluble but able to handle temps down to 0F would be ideal)
C) Comparable friction reduction to grease/soap.
D) I would imagine it needs to be thick like a grease/paste for our application too.
E) Removable without too much effort when we get ready to install the plastic finally (steam cleaner removable, etc)

Hopefully one of the wise sages on this site has some ideas. :)