Railroad signs use several distinct colors depending on the type of sign, but the two you’re most likely to encounter are the white crossbuck and the round yellow advance warning sign. Each color serves a specific purpose, making it easier for drivers to quickly recognize what’s ahead.
The White Crossbuck Sign
The most recognizable railroad sign is the crossbuck, the large X-shaped sign mounted right at the crossing. It has a white background with the words “RAILROAD CROSSING” in black letters, one word on each blade of the X. Federal standards require the white surface to be retroreflective, meaning it bounces light back toward your headlights so it’s visible at night. Even the back of each crossbuck blade must have a strip of reflective white material at least 2 inches wide running the full length, and the support post gets the same treatment from the sign down to about 2 feet above the road.
The Round Yellow Warning Sign
Before you reach the crossing itself, you’ll typically see a circular yellow sign with a black X and the letters “RR.” This is the advance warning sign (designated W10-1), and it’s the only circular sign in the standard American traffic sign system. The yellow background with black border and lettering follows the same color convention used for all warning signs on U.S. roads. It tells you a railroad crossing is ahead so you can start slowing down and watching for trains.
Other warning signs in the same family, like signs indicating a skewed crossing or a low ground clearance, also use the yellow-and-black color scheme. Nearly all railroad warning plaques follow this pattern.
Red and White Gate Arms
At crossings with active warning systems, the gate arms that lower across the road use alternating red and white diagonal stripes. The stripes sit at 45-degree angles, spaced at 16-inch intervals measured horizontally, and are fully retroreflective on both sides. At least three red lights are mounted along the arm. The red-and-white pattern is hard to miss, which is exactly the point: it signals an immediate physical barrier.
Blue Emergency Notification Signs
A smaller sign you might notice at railroad crossings is the blue-and-white Emergency Notification System (ENS) sign. These signs display the railroad’s emergency contact number and a unique identification number assigned by the U.S. Department of Transportation that pinpoints the exact crossing location. If a vehicle stalls on the tracks or you spot damage to the crossing equipment, the ENS sign gives you the information needed to call the railroad dispatcher and communicate precisely where you are.
Flashing Light Signal Colors
The flashing red lights at a crossing function like a stop sign or red traffic light. Red means stop and stay stopped until the lights stop flashing and any gates have fully raised. These are the signals drivers interact with, but railroad signals aimed at train engineers use a broader set of colors. Green means proceed at normal speed. Yellow means the current stretch of track is clear but the engineer should be ready to stop at the next signal. Red means stop and stay. A pale bluish-white light called “lunar white” tells the engineer to proceed at restricted speed.
Drivers don’t need to interpret the signals meant for trains, but understanding the system explains why you might see green, yellow, red, or white lights on signal towers near tracks.
Quick Color Reference by Sign Type
- Crossbuck (at the crossing): white background, black text
- Advance warning (circular): yellow background, black symbol and border
- Gate arms: red and white diagonal stripes
- Flashing crossing lights: red
- Emergency notification: blue and white
The color coding is consistent across the entire United States, governed by the Manual on Uniform Traffic Control Devices published by the Federal Highway Administration. So whether you’re driving through rural Kansas or downtown Chicago, the same colors mean the same things at every railroad crossing.