I posted pictures of my fantasy Warbonnet 6-4-4-4 elsewhere this morning. In completing it I used custom-made vinyl letters rather than decals, press on letters, or hand-painting. They worked out superbly.
Advantages: very easy to use, seem to be more durable than decals, very good looking, very customizable, and available in just about every font ever made, in many colors. Much, much thinner material than Chartpak and other pre-made vinyl letters you buy at Staples, etc.
Disadvantages: mine cost expensive $6.50 per "SANTA FE"). They are only available in letters 1/2" high or more. Ever site I checked had 1/2 inch or 1 inch as the smallest size they would make. I would dearly love to find a company that does this done to 1/8 inch. If anyone knows of one, please let me know!
These work well enough i will use them all I can in the future.
Here they are on my completed fantasy ATSF 6-4-4-4 streamlined cab forward steamer.
To get them I went to doityourselflettering.com. I am not necessarily endorsing them as better than many competitors they seem to have, but the website was easy to use and I got what I wanted and ordered in five days. On the site, you just type into a box the words, letterings numbers and symbols you want: I typed SANTA FE five times in a row. You pick the size. The smallest they would let me have was 1/2 inch high. You then pick the font you want: they have not just dozens, but hundreds if not thousands of fonts. I found a serif font called "Copper" which I had read was what ATSF used - regardless, if looked just like their lettering, so I picked it. You then pick the color: I ordered two sets, black, and silver. Here is that arrived, two strips of five SANTA FE each, in black and silver. (I've used two of the black sets for my loco by the time I took the photo below, so it has only three left.
Here is a detail of it.
The hardest part, actually, is peeling the backing off the letters and tape. They want to stick to it a bit. But I had no problems once i learned to watch for that.
the the backing off, the letters on on a thin, translucent tape, here they are sticky side up.
You position the tape - it is good it in transparent because you can see through it enough to help you position it on a loco, etc. Here, i just stuck it on the side of a clear plastic box I will use for parts. You press the tape and letters down . . . the letters are very sticky on the back and the tape just a little so . . .
the instructions did not call for this but I thought it was a good idea, so I pressed each letter home well . . .
The tape is very thin (2 mils) - even from half a foot away it looks like paint.