I missed your question about the tracks in an indermodal yard i guess lol
anyways, most of the intermodal yards that i have seen are concrete, but i have seen quite a few that are asphalt as well. Either way they both look good.
if your up for itand fairly patient person, i would highly suggesting using the Woodland Scenics Smooth-It road System. The stuff yeilds great results with some patients.
get yourself some Woodland Scenics Sculptamold, lay a coat of that down in and around the tracks, really all your doing is creating a base layer for the Smooth-It. This layer of the sculptamold does not have to be smooth at all, just make sure its a fairly thin coat and it does not come above the tops of the ties anywhere in the yard.
Take the Woodland Scenics Paving Tape and lay strips of it about 5-6" apart, i forget how wide the piece of plastic is that comes with the pack of paving tape, but that is the spreader you use to smooth the smooth-it
Next use the Woodland Scenics Smooth-It and mix it up with some water to get a mixture to the consistance of a medium to thick paste. Make sure you mix it well so there are no chunks of powder. Pour it over the area you want to have covered to represent concrete/asphalt, smooth it out so only the tops of the railheads are visable. This first coat of Smooth-It is a base coat and does not have to be absoultely smooth at all, its just a rough coat to get you started. While this is drying, take a NMRA HO scale standards track gauge and use the "Flangewheels" tool on the gauge to carve out the wheel flangeways for the tracks. This doesnt have to be perfect, just needs to be somewhat carved out so that it doesnt dry solid
After this is dry, remove any Paving Tape you may have used for the first coat of Smooth-It. On the second coat you mix up, make this one more watery. Fill in the gaps from the paving tape, and smooth out any gaps, dips.... that were left from the first coat of smooth-it. This coat is the semi smooth coat, so you want to try and make this coat smooth. Fill in the flangeways that you carved out with the NMRA Guage, making sure that the areas between the rails are semi-smooth. Its okay if these areas and the areas on the outsides of the rails are not perfect, as they are never smooth on the prototype.
While this second coat is drying, take your NMRA Guage and dig the flangways out again. At this point, the rails tops should be level with the yard, with only the flangeways dug out.
When this coat is dry, go over it one more time with a finer coat of Smooth-It. This is the final coat and this coat is to get any remaining dips.... smoothed out and smooth. 1 coat after this may be required also, depending on your preferences.
This is the way i do my grade crossings, and with a little patients and time, you get great results
Here are a couple pictures of one of my grade crossings i had on my old shelf layout
I plan on doing a tutorial on this when i start some of my modules, but until then, i hope this helps