Some of the white ones made for outdoor lighting I've seen this year look like they would have a nice color match with warm white for layout lighting. I haven't found that LED Christmas lights are very good for building lighting either, since the beam is so directional. They work well for things like floodlights, warning lights on water towers, and things like that. The one's I've found this year that have LED's small enough to work in locomotives or streetlights are the battery operated sets I got at Michaels. They are 1.5 volts and you get 20 white or mixed color lights for a buck on clearance. They even have a nice rubber sleeve to cover the wire connections and are easy to install without worrying about shorting.