How do railroad crossing signals work?
• United States
18 Dec 07
I'm not certain but I believe they are weight sensors some distance away from the crossing on both sides burried under the track. As long as the train is doing the speed limit at the crossing, they should trigger in time. If that's correct the crossing in the country with a higher speed limit for the trains then the distance of the sensors from the crossing should be greater.
27 Jan 08
Indeed, that isnt how they work at all. An electrical signal is put into the rails near the crossing. When a trian comes along, its metal wheels short the two rails together. That, tells the signal box to turn the lights on. Of course, it can get more complicated then that. But, thats the basics.