Greetings,
What is the difference between a semaphore signal and the 3 light signals used by the railroads?
And where are they normally placed?
I see the semaphore is often by a station, is it also used on the open main lines too?
I live near th BNSF main and have always just seen the stoplight version.
Just curious.
Mark in Texas
I think semaphores are just relics of the past. Are there any left in operation? I’ve certainly never seen one in real life.
A semaphore is just another version of the signals, they display the same aspects (arrangements) and indications (meanings) as color light signals do. Generally semaphore signals are older than color light signals.
Four types of signals, CTC absolute signals are placed at all entrances to a switch or crossover. So there would be 3 at each end of the siding. A a siding in ABS there would be two, one for each direction, beyond the points of the switch at each end of the siding. Intermediate signals would be spaced at regular intervals, depending on the speed of the track , between sidings. Interlockings signals would be placed at each entrance to an interlocking or each route through an interlocking.
And lastly the signals by a station are train order signals that tell the trains whether or not they have to pick up train orders.
Dave H.
Semaphores were quite common but “light” signals became very popular after WWII. Semaphores have always required more maintenance since there are motorized moving parts. Quite a few did survive into the 1990s on some Class 1 roads, usually in branch or remote lines. These signals can still be found on a number of tourist & museum railroads around the U.S.
Electric light signals are cheaper in maintenance and came in quite a variety. Pennsylvania and B&O had unique “triple light” signals within the signal head that positioned 3 lights just like semaphore signals. There are also 2 aspect and 3 aspect signals. The “target” signal has been very common for years railroads here on the east coast are going back to the 3 aspect signals.
If you want to go crazy, just look at the New York City’s Subway signal system! On yard entrances the signals almost remind one of a Christmas tree, signals everywhere!
There is a book called “Signaling your Model Railroad”. I think it’s a Kalmback book. Just check out a model railroad store. Chances are good that the sales rep would be familiar with it.
Working signals on a layout really add a nice, realistic flavor to the operations.
Hope this helps.[;)]
I have heard there are some still operating on the BNSF, on the old Northern Pacific route out west, maybe in Washington State.
When a semiphore is near a station, it is called a train order signal. It lets the trainmen know there are train orders to pick-up at the station. Yes, semiphores were used like target signals now in use. The semiphore was a mechanical devise and more prone to malfunction than the solid state electronic devises used now. Semiphores gave two indications, both a light and a signal arm. There where upper and lower quadrent semiphores. Uppers went from the arm horizontal, to the arm vertical up and lowers went from horizontal to arm vertical down. The indications were red-stop, Yellow-proceed and prepair to stop at the next signal and green-clear track ahead.
This is a simple explaination and almost the end of my knowledge of the subject. Probably someone else can add more!
Railroads normally replaced semaphores with colour lights on a one-for-one basis. Multiple semaphores would be replaced by multiple colour lights.
Semaphores could be either 2 or 3 indications, with a 45 degree angle indicating caution. If there were only 2 indications, and extra signal (“distant”) would be added in advance of the “home” signal. The distant would have a yellow arm and indicated caution.
Train order signals were, as far as I can tell, semaphores until the end of train orders. They would be mounted on the station, above the telegraph office, and mechanically operated. They weren’t linked to the block signals.