Signals, why where and when?

[dinwitty]

signals are placed to protect a location. The give information based on the indication.
Different railroads had different design standards, but the purpose is still the same.
Simple block signals will give Green for clear, Yellow for caution/slow-prepare to stop at next signal; and red for full stop.

BTW Tomar is not very far from where I am... 8-D

Adding another head gives a little more indication. The indication meaning varies if it is a block signal or an interlocking signal.

2 heads on a block signal general mean a speed indication.
On an interlocking signal it tells something of the route your taking and speed to run.
A signal can also have 3 heads but the meanings remain the same.

There are upper quantrant semaphores, lower quandrant, train order semaphores...
Color light signals can be the target single lense showing all colors or 3 light versions (or 2 light or even 4...)

Position light signals simulate what the semaphore does except with lights.
Single color position lights or color position lights.

Signals is another fascinating part of the hobby and really enhances the model.

[ndbprr]

So explain to me then how a signal tells a dispatcher where a train is in a block within 6'? I suspect that GPS is cpable of inches of measurement for bomb guidance and certain applications could get government approval with restrictions for that kind of requirement. But as I said and you overlooked it could happen in the next ten years and by the way communication will be through a device called a radio.

[dehusman]

You will still need something to communicate the indications to the train crews. You will also need track circuits to detect cars, etc on the main track and broken rails, etc.

By the way detection to within 30 ft is worthless to the railroads. they have to be able to place something to within 6 ft or less to use GPS to replace signaling.

Dave H.

[ndbprr]

This is off topic to an extent but with GPS access to within 30' of a location available to the general public today I think we could see the demise of signals in the next ten years for CTC. Exact location of a train is far more critical to a dispatcher than an area. Signals for route selection like turnouts would still be required however.

[IRONROOSTER]

This site has an article on signals http://www.trains.com/Content/Dynamic/Articles/000/000/003/035lsexb.asp
Enjoy
Paul

[Anonymous]

How you proceed with signals can be as simple or as complex as you want. Finding out what your prototype did is important but in all honesty, most systems the big guys use are pretty complex and cover much larger distances than we can fit on a model railroad. Most shortlines were dark (no signals). Do some research to find out about placement and type used by the railroad you are modeling. Even if all they do is sit there and look cool, they will be the right ones for your line and will enhance the realism of the scene..

Typically, model signals consist of a signal that controls power to a block of track next to the signal and one or more sensors and relays to keep track of trains leaving and entering the signal's control area. There are a myriad of control systems and ways to set up the trigger system for the signal. On the simpler end of things you can buy signal controllers that sense a passing train and run the signal through all its aspects after the train has passed. This is more for show than train control. If you are running DCC you can have operators stop at signals on their own with no power blocks controlled by signals, making things simpler and cheaper.

If you want the signals to operate trains automatically it increases complexity and cost significantly. If you want to operate protypically you will need some sort of remote centralized control board in most cases. Unless you have a large layout with extra room, you will have to make some comprimises and use some selective compression.

Years ago, we had a layout with signals controlled by relays and track sensors. We were able to run four trains on a double main completly automatically (look ma, no hands). It wasn't real prototypical, but it sure looked cool and visitors were always impressed to see trains stopping and starting on their own. My last layout had signals controlling blocks operated manually from control panels. On my new layout I will be using them simply as eye candy and to indicate the route selection of a few key hidden switches.

[dehusman]

Two real general types of signal systems. ABS (automatic block system) and CTC (centralized traffic control). In ABS the signals do not give authority for movement, the trains must have train orders or track warrants or some other authorty to move. In CTC the signals give trains authority to run.

In ABS at the end of each siding there will be a pair of signals (one facing each way) beyond the points of the switch (signal, switch, siding, switch, signal).

In CTC at the end of each siding there will be a signalat each entrance over the switch. So if there is a siding on an E-W track and we are at the west switch, the would be a signal west of the switch facing west, a signal at the clearance point east of the switch on the siding facing east and a signal at the clearance point east of the switch on the main facing east. The signal West of the switch will have two heads so it can display diverging indications (telling a train its going into the siding).

Between sidings both systems would have signals with single heads and number plates every 2-5 miles.

The number of heads in CTC or at an interlocking is usually determined by the different indications the signal can give. A real rough rule of thumb is that the number of heads is roughly equivalent to the number of routes. One route, one head, two routes, two heads, more than two routes, three heads. Once again that is a very rough rule of thumb.

Dave H.

[Anonymous]

where would a RR locate these signals? At every turnout? At either end of a runaround/passing siding? What would be the criteria for deciding where and what type of signal (one light/two light/three light) to use? Let's suspend the whole coordinated-fully automated signaling idea on a layout for a minute. What if I just wanted to put some non-powered signals on my waysides? How would I know how to place them?

[grandeman]

Electro, signalling will require some careful research and planning. We're considering all this right now too. It's a big project. Keep in mind that to do bi directional signals in three aspects the control system can get fairly complex. To make them work requires a minimum of three blocks. Check out the Digitrax site, they have the electronics to drive signals and detect trains in blocks. Right now, we have a box full of Circuitron boards that I'm not sure we'll use. I'm leaning toward the Digitrax system since I've seen it in use and it works well with much less wiring. Also, semophores require mechanical drives to operate the arm. This is usually a Tortoise machine and a special board to drive it.

The Grande used many searchlight type signals (one lens, three colors) like this.


They also used three lens standard units like this.


Hope this helps.

[West Coast S]

Let's see, Montana Rail link has some left, SP had some on the Sunset Route which have since been replaced by the "Yellow Borg". The Semaphore is among the longest lasting of all signal devices and among the oldest designs. Don't get too locked into the all modern concept, display for all to see that your railroad has some history.

Happy Modeling

Dave

[dehusman]

Try this site:

http://n6ecv.net/rrsignals.html

Dave H.

[mcouvillion]

Electrolove,

Your picture is of an upper-quadrant semaphore. Since there are two heads on the semaphore, the upper one is used to indicate the status of the next block on the main route, the lower head for the diverging route. The "upper quadrant" is a quarter circle from vertical to horizontal that is used for the indication. Most railroads used upper quadrant semaphores because the fail-safe indication is horizontal, the most restrictive indication. Horizontal indication is "STOP" or "Stop and Proceed", depending the specific location of the signal. Vertical indication is "Proceed", and the mid-way indication is "Proceed at Restricted Speed". A few railroads had lower-quadrant semaphores, where the horizontal indication was the same, but the arm moved down, where "Proceed" was almost, but not quite, vertical. If this semaphore failed, it's indication might be "Proceed" rather than the more restrictive "STOP".

As I indicated above, the horizontal indication can mean either "STOP" or "Stop and Proceed". If the semaphore has a number plate on the mast, the indication is "Stop and Proceed" at restricted speed, prepared to stop.

Try a Google search for semaphore indications. I have some information from the ATSF "Rules of the Operating Department, 1958" and from the Northern Pacific, but I don't have a web site to send you to.

One layout I operate on has all three-aspect semaphores, many dual head. The crew has found out how to modify them to accurately get all three aspects and runs them from Win-Lok on a Digitrax system. Think of two-aspect semaphores as a switch (ON / OFF) and three-aspect semaphores as the combination of two switches (ON + ON, ON + OFF, OFF + ON, and OFF + OFF). Using the routing feature of Win-Lok, you have the means to control your semaphores. We also figured out how to tighten up the likage so that the middle aspect is centered whether it comes from "Proceed" or "STOP". The semaphores are activated by Tortoise switch machines through Circuitron's remote linkage assembly.

Good Luck,

Mark C.

[MisterBeasley]

The semaphore in your picture has both a light and a semaphore arm. At night, the engineer will see the light first, red or green, to tell him/her if it is all right to proceed. In the daytime, the arm is horizontal for stop, vertical (or some other angle, depending on the particular model of semaphore) for go.

In the old days, communications between the controllers and engine cabs were not always reliable. Controllers would use these signals, and many other types, to signal the engineers. Typically, signals would be associated with blocks, and could be set to automatically indicate the presence of another train in the next block.

I'm using red/green LEDs to indicate the position of turnouts when approaching from the frog end. I used to wire my signals using block power in DC, but now that I'm running DCC I don't need blocks anymore. [:D]

Oregon Rail Supply (www.oregonrail.com) has a nice line of signals. I think you can get them through discounttrainsonline, too.

[electrolove]

I'm modelling an old era, D&RGW around 50 I think. Not yet fully decided. Yes this is a great beginning, thanks Medina1128.

[Medina1128]

I DO know it's called a semaphore, and it is used to control train movements. Unless I am mistaken, they were, for the most part, gone by the 1950s on US railways, maybe sooner, so if you are modeling a modern era, they would be out of place. I'm sure others can fill you in with more information, but this is a start.

[electrolove]

Look at this signal by tomar industries, so beautiful, wow.



I think signals is a very importent part of the scenery to give the layout the right look, but...

I live in Sweden and have never seen things like this in the real world, I don't even know what they are called or used for. There is so many different types of signals.

Can someone please tell me the name of the different kind of signals, why they are used and where they are used. Maybe someone can draw a very simple picture and place some signals to make it real easy to understand. I'm very interested to learn something about it.