I don't model in N scale, but someone at another forum wanted to know how to model N scale track in pavement without the large gaps needed for flangeways.  I had a piece of N scale flextrack lying around so I mulled the problem over and this is what I came up with. 

The pavement is just paper with a concrete texture printed on it.  If the paper between the rails is cut to the perfect width, it will stay in place without any shimming or gluing.  Pressing against the web of the rail creates enough friction to stay put.  The paper doesn't interfere with the wheels at all, even with those big pizza-cutter flanges on the test truck I used.

I created the original concrete texture in a 3D program called Blender and rendered out an image.  I loaded it into Photoshop Elements and enhanced it with images of real concrete that I found on the net.  These images were loaded into new layers and I used several merge modes (Overlay, Hard Light, and Luminance) to combine them with the original texture.  All of the weathering was also done in the computer.  I also used the Emboss filter to paint in some chips on the edges of the center section.

To cut out the paper for curves and turnouts you could set the paper over the track and then run your finger over the rail to leave an impression on the paper.  Then cut it out with an X-acto.  Or if you have a flatbed scanner, lay the turnout face-down on the scanner, scan it, and print it out full size.  Use this as a guide for cutting out the pavement.  Lay a ruler alongside the turnout on the scanner so you'll be able to tell if the print is the proper size.

Steve S