ATTENTION
A random sign seen at the end of the West 4th St station platform on the A, C, E & B, D, F, M lines in downtown Manhattan.
At first I wondered why this sign was here. It's obviously not for the passengers. After doing as little research I believe I found the answer.
The sign is positioned approximately were a typical train will stop and the motorman's window would be along side the sign.
The sign indicates colors for the "home signal" immediately ahead of this sign (perhaps 25 feet). Home signals indicate which way a train will go when passing through a switch. Green-over-Green typically means the train will travel straight through the switch (directly forward), and Green-over-Yellow means the train will "diverge" or take the track to the side (switch). However in this case, this signalling is reversed according to the track maps. Green-over-Green will switch in this case, and Green-over-Yellow will go straight. Some scribbling on the sign indicate where the different lines go for each lineup. The V, K, & H lines are retired and no longer run.
For the curious, "WD END" sign indicates "End of Wheel Detector" zone. From what I can find, the wheel detector is a speed sensing device used to control runaway or over speed trains. A train coming into the station too fast would be detected, and a "train stop" would be raised causing the brakes to be activated and forcing the train to a stop.
ATTENTION
A random sign seen at the end of the West 4th St station platform on the A, C, E & B, D, F, M lines in downtown Manhattan.
At first I wondered why this sign was here. It's obviously not for the passengers. After doing as little research I believe I found the answer.
The sign is positioned approximately were a typical train will stop and the motorman's window would be along side the sign.
The sign indicates colors for the "home signal" immediately ahead of this sign (perhaps 25 feet). Home signals indicate which way a train will go when passing through a switch. Green-over-Green typically means the train will travel straight through the switch (directly forward), and Green-over-Yellow means the train will "diverge" or take the track to the side (switch). However in this case, this signalling is reversed according to the track maps. Green-over-Green will switch in this case, and Green-over-Yellow will go straight. Some scribbling on the sign indicate where the different lines go for each lineup. The V, K, & H lines are retired and no longer run.
For the curious, "WD END" sign indicates "End of Wheel Detector" zone. From what I can find, the wheel detector is a speed sensing device used to control runaway or over speed trains. A train coming into the station too fast would be detected, and a "train stop" would be raised causing the brakes to be activated and forcing the train to a stop.