Incandescents have been around since the invention of the light bulb. Unfortunately, sometimes the lights weren't bright enough, or they would burn off too quickly. L.E.D. lights are much, much brighter than incandescents, last up to 10 times longer than incandescents, and use up to 75% less power than traditional incandescent lights, but are 16-40 times more expensive than incandescent bulbs.
Picture
taken from Flagstaff, AZ
This type is incandescent. There are two ways you can tell if lights are incandescent. One say is that the top center of the light never lights up. This is because of a thin piece that holds the tiny light bulb in the center of the light. Another way to tell is if the light fades in and out between flashes. If it does, it's incandescent.
Pictures
taken from Indianapolis, IN and Bakersfield, CA.
This is a good giveaway that the lights are L.E.D. There are lots (almost 200) little red lights that light up at once. The main difference between L.E.D. lights and incandescent, is that they are brighter, and provide better visibility when the lights light up, and a better life cycle. Incandescents have about a 1,000 hour life, and cost about $10 apiece, while L.E.D. lights last for 100,000 hours, but can cost $275 to $500 per light! When L.E.D. costs come down, expect to see LOTS of these at railroad crossings all around the U.S.
This light comes from US&S and is not one of my favorite L.E.D. lights.
Pictures taken from the WCH website, and from Beaumont, CA.
Here's a type of L.E.D. light that WCH sells. This isn't my favorite type of L.E.D. light, but it's popping up everywhere!
Pictures taken from Beaumont, CA and Lansing, CA.
These are a dead giveaway that these are L.E.D. L.E.D. lights can come either pre-colored, or in clear, which light up MUCH brighter than the pre-colored lights. Don't get too close to these kinds of lights, especially 200 of these at once. You could go blind from these. These kinds of L.E.D lights are getting a little easier to find, although the red pre-colored lights are pretty much staying around. I would like to see the clear, brighter lights take over though (to prevent confusion when the lights are shining directly on the lights during sunrise and sunset times.) Also, another good giveaway that these lights are L.E.D, are the fact that they don't fade in and out when they flash, although...
I think this light comes from WCH, but it's unconfirmed at the moment.
Picture
taken from Gilman, IL
These lights do fade in and out, but they are L.E.D, because there are the little L.E.D. dots inside.
It's unconfirmed, but it's believed that these lights come from Harmon.
Pictures
taken from Wilmington, CA and Redlands, CA
These lights are L.E.D, but there aren't any little "dots" inside the red circle. These lights do fade in and out between flashes though. These types of L.E.D. lights are more commonly found on traffic lights, which can use both "dotted" L.E.D. lights and "ball, non dotted" L.E.Ds, especially around California and Arizona. One popular type of these lights are from Dialight, which Safetran has a patent on, and sells through their website!
These kinds of lights are much more truer to incandsecents, they do fade in and out like incandescents, and are a lot brighter.
How to tell ball L.E.Ds apart? Take a look at the light when it's not flashing. You'll see lots of little diamond shapes. That's the giveaway.
Every railroad company, including G.E./HARMON, ALSTOM/AURORA, AND LEDtronics makes 12" L.E.D. lights. ALSTOM/AURORA, LEDtronics, WCH, Fabricated Metals, and General Signals all make 8" L.E.D. lights.