[Gpa113]

For my two 4 lane layouts I cheated and purchased a Beugler pin striping tool 

Very easy to use, after a bit of practice,  and I was impressed with the results. 
I used a little tin of good old Humbrol white paint, and practiced on some scrap cardboard until I was brave enough to move onto the tracks.....

The hardest bit was getting a Beugler pin striper at a decent price.  There are usually a few on ebay,  but it took me a couple of months of searching to obtain a used one for a sensible price.   They are American,  but very good, and of course you can always sell them back on after you have finished...