I saw a freight loco pulling 2 boxcars while I was driving along, approaching a grade crossing that had lights only (no gates). The tracks went behind a road-side factory and emerged right near the street. So, since I saw the train from some distance, I knew it was coming as it disappeared behind the factory. I slowed down and stopped. But no red lights! The loco barged out from behind the factory, barely 30 feet from the street. The engineer evidently knew the lights weren’t yet activated, because he crawled to a (belated) almost-stop. Suddenly the lights activated, and so he continued across the street. Question: are these signals cab-activated, and did he goof? Or are the signals supposed to sense the train, and malfunctioned?
Probably an “island” only insulated circuit that extends through the crossing and a few feet on each side. They are used on very low speed lines, we have some here on a short line railroad. The locomotive must get into the circuit to activate the lights. Probably not a malfunction.
I would agree with the above post;probably an “Island Only” circuit.
They generally extend about 100 feet each side of the street,mainly
used on very low trafficed lines,or in industrial areas.
The activation sequence is [ at least I was told by a NS signal supervisor] a product of the speed limit in the area of the crossing and it is set to allow 21 seconds for the crossing arm to come to the down position.
Island circuit or delayed circuit. As everyone else stated it is normal on sidings or lightly used lines or where switching occurs to prevent from holding up traffic when moving about.
Interesting! I am going to time the ones at our watch site. That may explain some of the action we see.
Plus, since there are 6 tracks - the engine will activate it on the first switch, then cross over to another one and the arms go up, then activate it on that switch so the arms go down. They look like they are exercising!
There are two ways to activate the crossing signals – a fixed distance circuit and speed sensitive circuits. I’d agree, too, that what you have there is an island circuit, with a short distance. As Loco and others said, common enough on low traffic lines (years ago many of these required the flagman to get off and flag the traffic). On other lines, as Sam noted, the fixed circuit is set up to allow 21 seconds at the speed limit. If it is a fixed circuit. There is a problem with these, though, in that if a train is moving slowly the devices will activate, and there will be a long pause – which results in drivers doing dumb things (not that they don’t, anyway…). More modern signalling uses a speed sensing device which figures out when the train will get to the crossing, and activates the crossing signals not less than 21 seconds (I think…) and not more than 35 seconds (I think…)(hopefully someone has a better handle on the times!) before the train gets there.
One of the crossings on the Adirondack Scenic’s Lake Placid - Saranac Lake line, adjacent to the Saranac Lake station, is too close to the station to allow for a standard circuit, so from the station side of the crossing, the signals must be manually triggered from a lock box. Part of that is due to the engine running around the train, since that is one end of the usual run.
I’ve see trains stopped within 100 feet of a crossing. As the train approaches the crossing, the signals activate, then go off when the train stops. When the train starts moving again, the circuit senses it and activates the signals.
On the other hand, I saw a crossing that had the signals activated by a train that was stopped (unplanned) pretty close to the end of the fixed circuit. Sure messed up highway traffic for a while, but the police were there to direct folks through.