I cleaned up my workbench last night when I had a few minutes of time and came across a package of eraser pens I picked up at the tool store a while ago that I forgot about.  One each of steel, brass and nylon.  This morning when I had a few free minutes before heading to work I thought I would try out the nylon pen to see how it did on the lettering on a boxcar.  I bought a pile of these Buffalo boxcars (see http://model-railroad-hobbyist.com/node/17923 ) for a very good price but there are

The first step is making a sketch of the desired piping.  The drawing below is not to scale, it simply shows the routing of the new piping.  Existing pipes are not shown. I will not measure the wire exactly.  Instead, I will lay it in and bend where appropriate.

Materials:

I found something interesting at Michael's (craft store) recently. It's a box of fancy brads, each one with a letter of the alphabet. Upper and lower case are both included. I think these could be useful for making large signs on buildings, even in the smaller scales. You'd have to cut off the tabs on the back of the letters.