How Railroad Crossing Signals Work

I love how Danny says he is going to provide the most basic explanation of crossing signals and then produces the most comprehensive explanation of the different types of crossing systems I've ever seen. Best. Youtuber. Ever.

My man, you have THE voice for broadcast or documentary. I would learn literally anything if you narrated it. Edit: and some quick google-fu tells me you already have a career in radio announcement and production. I knew something sounded right here! Hats off to you, sir.

I remember being a young kid back in the late 90s playing on the tracks. We were curious on how the crossing arms knew a train was coming and would watch around at what point the train activated the crossing arms. We saw where the activation started once the train left we laid a bed frame across the tracks and sure enough it activated the crossing arms. Being young and dumb we kept activating them until the police came to see whats going on. They yelled at us and called our parents

Literally not even into trains at all but somehow watched this from start to finish. Great entertainment

You know its a good day when Distant Signal uploads.

As a retired Signalman/Signal Maintainer hired by the Southern Railway System and retired off of the Norfolk Southern Railway: I approve this video!

It's been a while since I was a software engineer at Safetran 25 years ago, but your explanation of the various crossing control sensor types and how they work is pretty spot on for the technology in use at that time. Basically, a transmitter injects an AC signal on one side of the crossing, and is monitored by a receiver connection on the other side of the crossing. The track between the 2 connections is the island. If a train is on the crossing -- the "island" -- the signal is completely shorted by the train's axles and the receiver sees no signal at all, so that's how the electronics know a train is on the crossing. Otherwise, the train presents a rolling shunt across the tracks, and the two rails and the train constitute a electrical loop which is an inductor, electronically. The closer the train is to the crossing, the smaller the loop and the smaller the inductance. The electronics monitors the amplitude and phase of the received signal - which is changing when a train is moving in the approach circuit due to the changing inductance - and can tell from that whether the train is coming or going, how fast and how close it is, and in the case of a GCP can use that info to predict when the train will hit the crossing, and drop the gates at a predetermined number of seconds beforehand. Things do get a bit more complicated when there are multiple grade crossings with overlapping approach circuits. I'm sure crossing control systems are much more sophisticated now though.

Hell of a voice, clear deliberate pronunciation + enunciation, good tempo/pacing.... This guy's got to be a radio dj, voice over artist, or something... Can't you just imagine him saying "This is a test of emergency alert system, this is only a test"? Lol. Love this, subscribing now.

In a world gone wrong, Danny Harmon makes it alright. I learned something today. Thank you sir!

Never knew about radio tones activating crossing signals. Thanks Danny!

This is what the internet and YouTube are great for - educating people in something that is interesting. Thank You.

For many years, I had no idea how these signals knew how to activate for an impending train! You did a fantastic job explaining everything!

Whenever I hear that "Hello again Railfans" I feel like I can kick through a wall

This man is phenomenal, a great teacher and also has a great voice so he should be in Hollywood doing voice overs.

I've often wondered about the signals and how they work. A fast train activates a quarter mile away but a slow one just yards away. Thanks for the best explanation I could have recieved!

I came across this video in the recommended. I've been curious about this for about 20 years. i'm 31 now lol This is very detailed yet simple. Very well put together.

Once again when Danny Uploads a video we must stop what were doing and watch it!

Yay! A Danny video! - just one thing to add, whenever the gates are down, or the lights are flashing. Even if the crossing may be broken, NEVER drive around the gates. No matter what, even if the gates have been down for 2 hours, never go around because you never know what is coming!

It's amazing how much time and effort is put into logistics. They are really important and average people like myself don't thank people like railway engineers often enough.

Message art is so interesting. I've seen it before, and never realized that it originated with railroad employees as a way of communicating with each other. I always figured that it was just another tag like graffiti.