Quoted from Crash:

I work for an operator and we have somewhere in the ballpark of 12 pins on route and we exclusively use incandescent bulbs for the lamp matrix. I PM'd a couple of guys who had big bags of this stuff just sitting around and probably ended up with at least 400 free bulbs. Shouldn't have to buy any more for the foreseeable future, and on top of that many were high quality American made GE brand lamps. Those are much longer lasting and I stick them in hard to reach places or areas with high vibration.
We have considered going LED + LED OCD but the $200+ per machine cost of doing something like that is far too prohibitive. Plus I personally have a preference for the warm color and fade of incandescents anyway. GI has to be LED on a route game, there are just too many problems with incandescent GI.