I don't know about their white pens (assuming they have one) but I can say that a thin tipped Sharpie in black does NOT interact well with a coating of DullCoat, as I learned when I laboriously Sharpie'd in the tar patches on the "cracks" around the sewer covers and grates on a model road (HO), and then applied DullCoat to fasten down the chalks that I also used to weather the "concrete." The Sharpie lines all dissolved into a mess. I somewhat dissolved myself at that point.
I do believe Sharpie makes actual paint based pens as well as ink and perhaps the paint pens do not run. Having learned my lesson I will try on a piece of scrap before doing anything on the layout.
Not sure what I'd do in N but I wouldn't rule out decals.
AMENDED POSTING. I just thought of something. This may sound nuts but what about the smallest strip styrene in white. For example Evergreen .020 x .020" strip (their #120). If you scribed a line of about that width, cemented in the strip, and then sanded carefully if needed to make it flush or nearly so? It is very flexible and bends easily so curves would be no problem assuming you could scribe a line carefully enough.
Dave Nelson
Another option would be to use a draughtsman's ruling pen, as it would give very opaque lines, and the ability to adjust the width to suit your particular scale.
You'd likely need to use a straightedge for a guide, at least on straight portions of the road. For curves, a template cut from cardstock might be suitable, but they're also available to use in conjunction with a drawing compass.
For those more well-versed in CAD and other computer niceties, but not so much in "old school" methods, here's a photo...
You simply load the paint into the portion shown to the right, adjust the thumbwheel to get the desired width, then move it along the straightedge or curve template. Obviously, you'll need to keep refilling it as you work. If you've not used one before, a little practice beforehand may prove useful.
Wayne
Paint pens are certainly handy as I used them to add striping on the roads of my HO scale layout. A single coat of paint from these pens tends not to completely cover the grey which is great if you want a weathered look to your striping. However, even the "fine" tip paint pens would likely paint lines too thick for N scale. If you still want to try paint pens, I would recommend placing masking tape on your road surfaces to ensure you get the narrow striping width you desire. No need to mask the line length though.
Hornblower
I have a small T-trak module with roads built from styrene that I have painted gray and then weathered with an alcohol wash. I want to add road lines, but nothing real fancy. I don't want to do decals or transfers, but paint pens or colored pencils sound good.
I need basically white (in the Japanese area I am modeling, they didn't use yellow).
Can anyone recommend a certain type of paint pen suitable for N scale, or perhaps a brand and size of colored pencil? I will practice first of course!Thanks.
Modeling the D&H in 1984: http://dandhcoloniemain.blogspot.com/